The immune status of migrant populations in Europe and implications for vaccine-preventable disease control: a systematic review and meta-analysis

BACKGROUND

Ensuring vaccination coverage reaches established herd immunity thresholds (HIT) is the cornerstone of any vaccination programme. Diverse migrant populations in European countries have been associated with cases of vaccine-preventable diseases (VPD) and outbreaks, yet it is not clear to what extent they are an under-immunised group.

METHODS

We did a systematic review and meta-analysis to synthesise peer-reviewed published primary research reporting data on the immune status of migrants in EU/EEA countries, the UK and Switzerland, calculating their pooled immunity coverage for measles, mumps, rubella, and diphtheria using random-effects models. We searched on Web of Science, Embase, Global Health and MEDLINE (January 1st 2000 to June 10th 2022), with no language restrictions. The protocol is registered with PROSPERO (CRD42018103666).

FINDINGS

Of 1103 abstracts screened, 62 met eligibility criteria, of which 39 were included in the meta-analysis. The meta-analysis included 75 089 migrants, predominantly from outside Europe. Pooled immunity coverage among migrant populations was well below the recommended HIT for diphtheria (n = 7, 57.4% [95% CI: 43.1-71.7%] I2 = 99% vs HIT 83-86%), measles (n = 21, 83.7% [95% CI: 79.2-88.2] I2 = 99% vs HIT 93-95%), and mumps (n = 8, 67.1% [95% CI: 50.6-83.6] I2 = 99% vs HIT 88-93%), and midway for rubella (n = 29, 85.6% [95% CI: 83.1-88.1%] I2 = 99% vs HIT 83-94%), with high heterogeneity across studies.

INTERPRETATION

Migrants in Europe are an under-immunised group for a range of important VPDs, with this study reinforcing the importance of engaging children, adolescents, and adults in 'catch-up' vaccination initiatives on arrival for vaccines, doses, and boosters they may have missed in their home countries. Co-designing strategies to strengthen catch-up vaccination across the life-course in under-immunised groups is an important next step if we are to meet European and global targets for VPD elimination and control and ensure vaccine equity.

"As a patient I do not belong to the clinic, I belong to the community." Co-developing a multi-level, person-centred tuberculosis stigma intervention in Cape Town, South Africa

Background

Anticipated, internal, and enacted stigma are major barriers to TB care engagement, and directly impact patient well-being. Unfortunately, targeted stigma interventions are lacking. We aimed to co-develop a person-centred stigma intervention with TB-affected community members and health workers in South Africa.

Methods

Using a community-based participatory research approach, we conducted ten group discussions with people diagnosed with TB (past or present), caregivers, and health workers (total n=87) in Khayelitsha, Cape Town. Group discussions were facilitated by TB survivors. Discussion guides explored experiences and drivers of stigma and used human-centred design principles to co-develop solutions. Recordings were transcribed, coded, thematically analysed and then further interpreted using the socio-ecological model.

Results

Intervention components across socio-ecological levels shared common behaviour change strategies, namely education, empowerment, engagement, and innovation. At the individual level, participants recommended counselling to improve TB knowledge and provide ongoing support. TB survivors can guide messaging to nurture stigma resilience by highlighting that TB can affect anyone and is curable, and provide lived experiences of TB to decrease internal stigma. At the interpersonal level, support clubs and family-centred counselling were suggested to dispel TB-related myths and foster support. At the institutional level, health worker stigma reduction training informed by TB survivor perspectives was recommended. Consideration of how integration of TB/HIV care services may exacerbate TB/HIV intersectional stigma and ideas for restructured service delivery models were suggested to decrease anticipated and enacted stigma. At the community level, participants recommended awareness-raising events led by TB survivors, including TB information in school curricula. At the policy level, solutions focused on reducing the visibility generated by a TB diagnosis and resultant stigma in health facilities and shifting tasks to community health workers.

Conclusions

Decreasing TB stigma requires a multi-level approach. Co-developing a person-centred intervention with affected communities is feasible and generates stigma intervention components that are directed and implementable. Such community-informed intervention components should be prioritised by TB programs, including integrated TB/HIV care services.

"This is an illness. No one is supposed to be treated badly": Community-based stigma assessments in South Africa to inform TB stigma intervention design

Background

Though TB-related stigma is a recognized barrier to care, interventions are lacking and gaps remain in understanding the drivers and experiences of TB-related stigma. We undertook community-based mixed methods stigma assessments to inform stigma intervention design.

Methods

We adapted the Stop TB Partnership stigma assessment tool, and trained three peer research associates (PRAs; two TB survivors, one community health worker) to conduct surveys with people with TB (PWTB, n=93) and caregivers of children with TB (n=24) at peri-urban and rural clinic sites in Khayelitsha, Western Cape, and Hammanskraal, Gauteng Province, South Africa. We descriptively analyzed responses for each stigma experience (anticipated, internal, and enacted), calculated stigma scores, and undertook generalized linear regression analysis. We further conducted 25 in-depth interviews with PWTB (n=22) and caregivers TB (n=3). Using inductive thematic analysis, we performed open coding to identify emergent themes, and selective coding to identify relevant quotes. Themes were organised using the CARD (Constraints, Actions, Risks and Desires) framework.

Results

Surveys revealed at least one-third of PWTB and one-quarter of caregivers report experiences of anticipated, internal, and/or enacted stigma, which affected engagement throughout the care cascade. Participants in rural locations (compared to peri-urban) reported higher anticipated, internal, and enacted stigma (β-coefficient 0.72, 0.71, and 0.74). Interview participants described how stigma experiences, including HIV intersectional stigma, act individually and in concert as key constraints to impede care, and underpins failure to disclose a TB diagnosis, isolation, and exclusion. Stigma resilience arose through understanding that TB can affect anyone and should not diminish self-worth. Risks of stigma, driven by fears related to disease severity and infectiousness, led to care disengagement and impaired psychological wellbeing. Participants desired counselling, identifying a specific role for TB survivors as peer counsellors, and community education.

Conclusions

Stigma is highly prevalent and negatively impacts TB care and the well-being of PWTB, warranting its assessment as a primary outcome indicator rather than intermediary contributor to poor cascade outcomes. Multicomponent stigma interventions are needed, including counselling for PWTB and education for health workers and communities. Such interventions must incorporate contextual differences based on gender or setting, and use survivor-guided messaging to foster stigma resilience.

An acidic microenvironment in Tuberculosis increases extracellular matrix degradation by regulating macrophage inflammatory responses

Mycobacterium tuberculosis (M.tb) infection causes marked tissue inflammation leading to lung destruction and morbidity. The inflammatory extracellular microenvironment is acidic, however the effect of this acidosis on the immune response to M.tb is unknown. Using RNA-seq we show that acidosis produces system level transcriptional change in M.tb infected human macrophages regulating almost 4000 genes. Acidosis specifically upregulated extracellular matrix (ECM) degradation pathways with increased expression of Matrix metalloproteinases (MMPs) which mediate lung destruction in Tuberculosis. Macrophage MMP-1 and -3 secretion was increased by acidosis in a cellular model. Acidosis markedly suppresses several cytokines central to control of M.tb infection including TNF-α and IFN-γ. Murine studies demonstrated expression of known acidosis signaling G-protein coupled receptors OGR-1 and TDAG-8 in Tuberculosis which are shown to mediate the immune effects of decreased pH. Receptors were then demonstrated to be expressed in patients with TB lymphadenitis. Collectively, our findings show that an acidic microenvironment modulates immune function to reduce protective inflammatory responses and increase extracellular matrix degradation in Tuberculosis. Acidosis receptors are therefore potential targets for host directed therapy in patients.

Clinicopathological profile of peritoneal tuberculosis and a new scoring model for predicting mortality: an international ID-IRI study

Existing literature about peritoneal tuberculosis (TBP) is relatively insufficient. The majority of reports are from a single center and do not assess predictive factors for mortality. In this international study, we investigated the clinicopathological characteristics of a large series of patients with TBP and determined the key features associated with mortality. TBP patients detected between 2010 and 2022 in 38 medical centers in 13 countries were included in this retrospective cohort. Participating physicians filled out an online questionnaire to report study data. In this study, 208 patients with TBP were included. Mean age of TBP cases was 41.4 ± 17.5 years. One hundred six patients (50.9%) were females. Nineteen patients (9.1%) had HIV infection, 45 (21.6%) had diabetes mellitus, 30 (14.4%) had chronic renal failure, 12 (5.7%) had cirrhosis, 7 (3.3%) had malignancy, and 21 (10.1%) had a history of immunosuppressive medication use. A total of 34 (16.3%) patients died and death was attributable to TBP in all cases. A pioneer mortality predicting model was established and HIV positivity, cirrhosis, abdominal pain, weakness, nausea and vomiting, ascites, isolation of Mycobacterium tuberculosis in peritoneal biopsy samples, TB relapse, advanced age, high serum creatinine and ALT levels, and decreased duration of isoniazid use were significantly related with mortality (p < 0.05). This is the first international study on TBP and is the largest case series to date. We suggest that using the mortality predicting model will allow early identification of high-risk patients likely to die of TBP.

Country-specific approaches to latent tuberculosis screening targeting migrants in EU/EEA* countries: A survey of national experts, September 2019 to February 2020

Background

Migrants in low tuberculosis (TB) incidence countries in the European Union (EU)/European Economic Area (EEA) are an at-risk group for latent tuberculosis infection (LTBI) and are increasingly included in LTBI screening programmes.

Aim

To investigate current approaches and implement LTBI screening in recently arrived migrants in the EU/EEA and Switzerland.

Methods

At least one TB expert working at a national level from the EU/EEA and one TB expert from Switzerland completed an electronic questionnaire. We used descriptive analyses to calculate percentages, and framework analysis to synthesise free-text responses.

Results

Experts from 32 countries were invited to participate (30 countries responded): 15 experts reported an LTBI screening programme targeting migrants in their country; five reported plans to implement one in the near future; and 10 reported having no programme. LTBI screening was predominantly for asylum seekers (n = 12) and refugees (n = 11). Twelve countries use ‘country of origin’ as the main eligibility criteria. The countries took similar approaches to diagnosis and treatment but different approaches to follow-up. Six experts reported that drop-out rates in migrants were higher compared with non-migrant groups. Most of the experts (n = 22) called for a renewed focus on expanding efforts to screen for LTBI in migrants arriving in low-incidence countries.

Conclusion

We found a range of approaches to LTBI screening of migrants in the EU/EEA and Switzerland. Findings suggest a renewed focus is needed to expand and strengthen efforts to meaningfully include migrants in these programmes, in order to meet regional and global elimination targets for TB.

Clinical standards for the diagnosis, treatment and prevention of TB infection

BACKGROUND: Tuberculosis (TB) preventive therapy (TPT) decreases the risk of developing TB disease and its associated morbidity and mortality. The aim of these clinical standards is to guide the assessment, management of TB infection (TBI) and implementation of TPT.METHODS: A panel of global experts in the field of TB care was identified; 41 participated in a Delphi process. A 5-point Likert scale was used to score the initial standards. After rounds of revision, the document was approved with 100% agreement.RESULTS: Eight clinical standards were defined: Standard 1, all individuals belonging to at-risk groups for TB should undergo testing for TBI; Standard 2, all individual candidates for TPT (including caregivers of children) should undergo a counselling/health education session; Standard 3, testing for TBI: timing and test of choice should be optimised; Standard 4, TB disease should be excluded prior to initiation of TPT; Standard 5, all candidates for TPT should undergo a set of baseline examinations; Standard 6, all individuals initiating TPT should receive one of the recommended regimens; Standard 7, all individuals who have started TPT should be monitored; Standard 8, a TBI screening and testing register should be kept to inform the cascade of care.CONCLUSION: This is the first consensus-based set of Clinical Standards for TBI. This document guides clinicians, programme managers and public health officers in planning and implementing adequate measures to assess and manage TBI.

Neutrophil-Mediated Immunopathology and Matrix Metalloproteinases in Central Nervous System - Tuberculosis

Tuberculosis (TB) remains one of the leading infectious killers in the world, infecting approximately a quarter of the world’s population with the causative organism Mycobacterium tuberculosis (M. tb). Central nervous system tuberculosis (CNS-TB) is the most severe form of TB, with high mortality and residual neurological sequelae even with effective TB treatment. In CNS-TB, recruited neutrophils infiltrate into the brain to carry out its antimicrobial functions of degranulation, phagocytosis and NETosis. However, neutrophils also mediate inflammation, tissue destruction and immunopathology in the CNS. Neutrophils release key mediators including matrix metalloproteinase (MMPs) which degrade brain extracellular matrix (ECM), tumor necrosis factor (TNF)-α which may drive inflammation, reactive oxygen species (ROS) that drive cellular necrosis and neutrophil extracellular traps (NETs), interacting with platelets to form thrombi that may lead to ischemic stroke. Host-directed therapies (HDTs) targeting these key mediators are potentially exciting, but currently remain of unproven effectiveness. This article reviews the key role of neutrophils and neutrophil-derived mediators in driving CNS-TB immunopathology.

The relationship between mental health and risk of active tuberculosis: a systematic review

OBJECTIVES

Tuberculosis (TB) and mental illnesses are highly prevalent globally and often coexist. While poor mental health is known to modulate immune function, whether mental disorders play a causal role in TB incidence is unknown. This systematic review examines the association between mental health and TB disease risk to inform clinical and public health measures.

DESIGN

Systematic review, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

SEARCH STRATEGY AND SELECTION CRITERIA

MEDLINE, PsycINFO and PsycEXTRA databases were searched alongside reference list and citation searching. Inclusion criteria were original research studies published 1 January 1970-11 May 2020 reporting data on the association between mental health and TB risk.

DATA EXTRACTION, APPRAISAL AND SYNTHESIS

Data were extracted on study design and setting, sample characteristics, measurement of mental illness and TB, and outcomes including effect size or prevalence. Studies were critically appraised using Critical Appraisal Skills Programme (CASP) and Appraisal Tool for Cross-Sectional Studies (AXIS) checklists.

RESULTS

1546 records published over 50 years were screened, resulting in 10 studies included reporting data from 607 184 individuals. Studies span across Asia, South America and Africa, and include mood and psychotic disorders. There is robust evidence from cohort studies in Asia demonstrating that depression and schizophrenia can increase risk of active TB, with effect estimates ranging from HR=1.15 (95% CI 1.03 to 1.28) to 2.63 (95% CI 1.74 to 3.96) for depression and HR=1.52 (95% CI 1.29 to 1.79) to RR=3.04 for schizophrenia. These data align with evidence from cross-sectional studies, for example, a large survey across low-income and middle-income countries (n=242 952) reports OR=3.68 (95% CI 3.01 to 4.50) for a depressive episode in those with TB symptoms versus those without.

CONCLUSIONS

Individuals with mental illnesses including depression and schizophrenia experience increased TB incidence and represent a high-risk population to target for screening and treatment. Integrated care for mental health and TB is needed, and interventions tackling mental illnesses and underlying drivers may help reduce TB incidence globally.

PROSPERO REGISTRATION NUMBER

CRD42019158071.

Participatory approaches in the development of health interventions for migrants: a systematic review

OBJECTIVE

Analysis of participatory approaches to developing health interventions for migrants and how approaches embody core participatory principles of inclusivity and democracy.

DESIGN

A systematic review of original articles. Electronic searches within the databases MEDLINE, Embase, Global Health and PsychINFO (from inception-November 2020).

ELIGIBILITY CRITERIA FOR STUDY SELECTION

Original peer-reviewed articles reporting research to develop and implement a health intervention for migrants, incorporating participatory approaches. We defined migrants as foreign-born individuals. Only articles reporting the full research cycle (inception, design, implementation, analysis, evaluation, dissemination) were included.

DATA EXTRACTION

We extracted information related to who was involved in research (migrants or other non-academic stakeholders), the research stage at which they were involved (inception, design, implementation, analysis, evaluation, dissemination), the method of their involvement and how this aligned with the core principles of participatory research-categorising studies as exhibiting active or pseudo (including proxy and indirect) participation.

RESULTS

1793 publications were screened, of which 28 were included in our analysis. We found substantial variation in the application of participatory approaches in designing health interventions targeting migrants: across 168 individual research stages analysed across the 28 studies, we recorded 46 instances of active participation of migrants, 30 instances of proxy participation and 24 instances of indirect participation. All studies involved non-academic stakeholders in at least one stage of the research, only two studies exhibited evidence of active participation of migrants across all research stages. Evidence is limited due to the variability of terms and approaches used.

CONCLUSIONS

Important shortfalls in the meaningful inclusion of migrants in developing health interventions exist, suggesting a more rigorous and standardised approach is warranted to better define and deliver participatory research and improve quality.

REGISTRATION

This review followed Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines and is registered on the Open Science Framework (osf.io/2bnz5).

A systematic review of the association between mental health and tuberculosis disease risk

Background

Tuberculosis (TB) and mental illnesses are highly prevalent globally and often co-exist. Whilst poor mental health is known to modulate immune function, whether mental disorders causally increase TB incidence is unknown. This systematic review examines the association between mental health and TB disease risk to inform clinical and public health measures.

Methods

We carried out a systematic review following PRISMA guidelines (PROSPERO CRD42019158071). We searched MEDLINE, PsycINFO and PsycEXTRA databases alongside reference list and citation searching. Inclusion criteria were original research studies published 01/01/1970-11/05/2020 reporting data on the relationship between mental health and risk of TB disease. CASP and AXIS checklists were used to critically appraise included studies.

Results

We screened 1546 records published over 50 years, resulting in data synthesised from 607,184 individuals. Settings include Asia, South America, and Africa, and both mood (e.g. depression) and psychotic (e.g. schizophrenia) disorders are investigated. Robust evidence from cohort studies in Asia shows that depression and schizophrenia can increase risk of TB disease, with effect estimates ranging from HR = 1.15 [95% CI 1.03-1.28] to HR = 2.63 [95% CI 1.74-3.96] for depression and HR = 1.52 [95% CI 1.29-1.79] to RR = 3.04 for schizophrenia, and a dose-response relationship reported in one study. These data are consistent with data from cross-sectional studies, such as a large survey across low- and middle-income countries (n = 242,952) reporting OR = 3.36 [95% CI 3.01-4.50] for a depressive episode in those with TB versus those without.

Conclusions

Individuals with mental illnesses including depression and schizophrenia experience increased TB incidence and represent a high-risk population to target for screening and treatment. Integrated care for mental health and TB is needed, and interventions tackling mental illnesses and underlying drivers may help reduce TB incidence globally.

Key messages

This systematic review examines data from 607,184 individuals and finds evidence that mental health is a risk factor for TB disease. Those suffering from depression and schizophrenia are an at-risk population that could be identified and targeted for TB screening and treatment.

Migration and outbreaks of vaccine-preventable disease in Europe: a systematic review

Migrant populations are one of several underimmunised groups in the EU or European Economic Area (EU/EEA), yet little is known about their involvement in outbreaks of vaccine-preventable diseases. This information is vital to develop targeted strategies to improve the health of diverse migrant communities. We did a systematic review (PROSPERO CRD42019157473; Jan 1, 2000, to May 22, 2020) adhering to PRISMA guidelines, to identify studies on vaccine-preventable disease outbreaks (measles, mumps, rubella, diphtheria, pertussis, polio, hepatitis A, varicella, Neisseria meningitidis, and Haemophilus influenzae) involving migrants residing in the EU/EEA and Switzerland. We identified 45 studies, reporting on 47 distinct vaccine-preventable disease outbreaks across 13 countries. Most reported outbreaks involving migrants were of measles (n=24; 6496 cases), followed by varicella (n=11; 505 cases), hepatitis A (n=7; 1356 cases), rubella (n=3; 487 cases), and mumps (n=2; 293 cases). 19 (40%) outbreaks, predominantly varicella and measles, were reported in temporary refugee camps or shelters. Of 11 varicella outbreaks, nine (82%) were associated with adult migrants. Half of measles outbreaks (n=11) were associated with migrants from eastern European countries. In conclusion, migrants are involved in vaccine-preventable disease outbreaks in Europe, with adult and child refugees residing in shelters or temporary camps at particular risk, alongside specific nationality groups. Vulnerability varies by disease, setting, and demographics, highlighting the importance of tailoring catch-up vaccination interventions to specific groups in order to meet regional and global vaccination targets as recommended by the new Immunisation Agenda 2030 framework for action. A better understanding of vaccine access and intent in migrant groups and a greater focus on co-designing interventions is urgently needed, with direct implications for COVID-19 vaccine delivery.

Initiation and completion of treatment for latent tuberculosis infection in migrants globally: a systematic review and meta-analysis

Background

Latent tuberculosis infection (LTBI) is one of the most prevalent infections globally and can lead to the development of active tuberculosis disease. In many low-burden countries, LTBI is concentrated within migrant populations often because of a higher disease burden in the migrant's country of origin. National programmes consequently focus on screening and treating LTBI in migrants to prevent future tuberculosis cases; however, how effective these programmes are is unclear. We aimed to assess LTBI treatment initiation and outcomes among migrants, and the factors that influence both.

Methods

For this systematic review and meta-analysis, we searched Embase, MEDLINE, and Global Health, and manually searched grey literature from Jan 1, 2000, to April 21, 2020. We included primary research articles reporting on LTBI treatment initiation or completion, or both, in migrants and excluded articles in which data were not stratified by migrant status, or in which the data were related to outcomes before 2000. There were no geographical or language restrictions. All included studies were quality appraised using recognised tools depending on their design, and we assessed the heterogeneity of analyses using I². We extracted data on the numbers of migrants initiating and completing treatment. Our primary outcomes were LTBI treatment initiation and completion in migrants (defined as foreign-born). We used random-effects meta-regression to examine the influence of factors related to these outcomes. The study is registered with PROSPERO (CRD42019140338).

Findings

2199 publications were retrieved screened, after which 39 publications from 13 mostly high-income, low-burden countries were included in our analyses, with treatment initiation and completion data reported for 31 598 migrants positive for LTBI, with not all articles reporting the full pathway from initiation to completion. The pooled estimate for the true proportion of migrants testing positive who initiated treatment was 69% (95% CI 51–84; I²= 99·62%; 4409 of 8764). The pooled estimate for the true proportion of migrants on treatment in datasets, who subsequently completed it was 74% (95% CI = 66–81; I²= 99·19%; 15 516 of 25 629). Where data were provided for the entire treatment pathway, the pooled estimate for the true proportion of migrants who initiated and completed treatment after a positive test was only 52% (95% CI 40–64; I²= 98·90%; 3289 of 6652). Meta-regression showed that LTBI programmes are improving, with more recent reported data (2010–20) associated with better rates of treatment initiation and completion, with multiple complex factors affecting treatment outcomes in migrants.

Interpretation

Although our analysis highlights that LTBI treatment initiation and completion in migrants has improved considerably from 2010–20, there is still room for improvement, with drop out reported along the entire treatment pathway. The delivery of these screening and treatment programmes will require further strengthening if the targets to eradicate tuberculosis in low-incidence countries are to be met, with greater focus needed on engaging migrants more effectively in the clinic and understanding the diverse and unique barriers and facilitators to migrants initiating and completing treatment.

Funding

European Society of Clinical Microbiology and Infectious Diseases, the Rosetrees Trust, the National Institute for Health Research, and the Academy of Medical Sciences.

Doxycycline host-directed therapy in human pulmonary tuberculosis

BACKGROUNDMatrix metalloproteinases (MMPs) are key regulators of tissue destruction in tuberculosis (TB) and may be targets for host-directed therapy. We conducted a phase II double-blind, randomized, controlled trial investigating doxycycline, a licensed broad-spectrum MMP inhibitor, in patients with pulmonary TB.METHODSThirty patients with pulmonary TB were enrolled within 7 days of initiating anti-TB treatment and randomly assigned to receive either 100 mg doxycycline or placebo twice a day for 14 days, in addition to standard care.RESULTSWhole blood RNA-sequencing demonstrated that doxycycline accelerated restoration of dysregulated gene expression in TB towards normality, rapidly down-regulating type I and II interferon and innate immune response genes, and up-regulating B-cell modules relative to placebo. The effects persisted for 6 weeks after doxycycline discontinuation, concurrent with suppressed plasma MMP-1. Doxycycline significantly reduced sputum MMP-1, -8, -9, -12 and -13, suppressed type I collagen and elastin destruction, reduced pulmonary cavity volume without altering sputum mycobacterial loads, and was safe.CONCLUSIONAdjunctive doxycycline with standard anti-TB treatment suppressed pathological MMPs in PTB patients. Larger studies on adjunctive doxycycline to limit TB immunopathology are merited.TRIAL REGISTRATIONClinicalTrials.gov NCT02774993.FUNDINGSingapore National Medical Research Council (NMRC/CNIG/1120/2014, NMRC/Seedfunding/0010/2014, NMRC/CISSP/2015/009a); the Singapore Infectious Diseases Initiative (SIDI/2013/013); National University Health System (PFFR-28 January 14, NUHSRO/2014/039/BSL3-SeedFunding/Jul/01); the Singapore Immunology Network Immunomonitoring platform (BMRC/IAF/311006, H16/99/b0/011, NRF2017_SISFP09); an ExxonMobil Research Fellowship, NUHS Clinician Scientist Program (NMRC/TA/0042/2015, CSAINV17nov014); the UK Medical Research Council (MR/P023754/1, MR/N006631/1); a NUS Postdoctoral Fellowship (NUHSRO/2017/073/PDF/03); The Royal Society Challenge Grant (CHG\R1\170084); the Sir Henry Dale Fellowship, Wellcome Trust (109377/Z/15/Z); and A*STAR.

Platelet Activation and the Immune Response to Tuberculosis

In 2019 10 million people developed symptomatic tuberculosis (TB) disease and 1.2 million died. In active TB the inflammatory response causes tissue destruction, which leads to both acute morbidity and mortality. Tissue destruction in TB is driven by host innate immunity and mediated via enzymes, chiefly matrix metalloproteinases (MMPs) which are secreted by leukocytes and stromal cells and degrade the extracellular matrix. Here we review the growing evidence implicating platelets in TB immunopathology. TB patients typically have high platelet counts, which correlate with disease severity, and a hypercoagulable profile. Platelets are present in human TB granulomas and platelet-associated gene transcripts are increased in TB patients versus healthy controls. Platelets most likely drive TB immunopathology through their effect on other immune cells, particularly monocytes, to lead to upregulation of activation markers, increased MMP secretion, and enhanced phagocytosis. Finally, we consider current evidence supporting use of targeted anti-platelet agents in the treatment of TB due to growing interest in developing host-directed therapies to limit tissue damage and improve treatment outcomes. In summary, platelets are implicated in TB disease and contribute to MMP-mediated tissue damage via their cellular interactions with other leukocytes, and are potential targets for novel host-directed therapies.

Long-term risk of tuberculosis among migrants according to migrant status: a cohort study

BACKGROUND

The majority of tuberculosis (TB) cases in low-incidence countries occur in migrants. Only few studies have assessed the long-term TB risk in migrants after immigration, and datasets have not considered this across a range of diverse migrant groups. This nationwide study aimed to investigate long-term TB risk among migrants according to migrant status and region of origin.

METHODS

This cohort study included all migrants aged  ≥ 18 years who obtained residence in Denmark from 1993 to 2015, with a mean follow-up of 10.8 years [standard deviation (SD) 7.3]. Migrants were categorized based on legal status of residence and region of origin. Incidence rates (IR) and rate ratios (IRR) were estimated by Poisson regression.

RESULTS

A total of 142 314 migrants were included. Across all migrants, the TB risk was highest during year 1 of residence (IR 275/100 000 person-years; 95% CI 249-305) followed by a gradual decline, though TB risk remained high for over a decade. Compared with the Danish-born population, the IRRs after 7-8 years were particularly higher among former asylum seekers (IRR 31; 95% CI 20-46), quota refugees (IRR 31; 95% CI 16-71), and family-reunified with refugees (IRR 22; 95% CI 12-44). Sub-Saharan African migrants also experienced elevated risk (IRR 75; 95% CI 51-109). The proportion of migrants with pulmonary TB was 52.4%.

CONCLUSION

All migrant groups experienced an initial high TB risk, but long-term risk remained high in key migrant groups. Most European countries focus TB screening on or soon after arrival. Our study suggests that approaches to TB screening should be adapted, with migrant populations benefiting from long-term access to preventive health services.

"It's a life you're playing with": A qualitative study on experiences of NHS maternity services among undocumented migrant women in England

BACKGROUND

Undocumented migrant women experience complex barriers to maternity services, are less likely to receive the recommended level of maternity care, and have poorer obstetric outcomes than non-migrant women. There are concerns increasing restrictions on entitlement to health services have a detrimental impact on access to services and obstetric outcomes, particularly among undocumented migrant women. The study aimed to investigate the experiences of undocumented migrant women who have been pregnant in England, and factors affecting access to care and health outcomes.

METHODS

We conducted in-depth semi-structured interviews June-December 2017 with a purposive sample of migrant women born outside the UK (aged>18) who had experiences of pregnancy and undocumented status (without permission to reside) in the UK, recruited through Doctors of the World (DOTW) UK. Interpreting services were used on request. Interviews were recorded, transcribed, and analysed using thematic analysis. Ethical approval: Imperial College London Research Ethics Committee (ICREC reference: 17IC3924).

RESULTS

Semi-structured interviews were conducted with 20 participants, 10 of whom had their first antenatal appointment after the national target of 13 weeks, and nine of whom reported complications. Themes defining women's experiences of pregnancy included: restricted agency, intersecting stressors, and an ongoing cycle of precarity, defined by legal status, social isolation, and economic status.

CONCLUSIONS

This study provides new evidence of women's experiences of pregnancy in the UK in the context of increasingly restrictive health policies including charging and data sharing. Six recommendations are made to ensure the UK and other migrant receiving countries work towards reducing inequalities and achieving national and global targets for maternal and child health and universal health coverage.

Invariant Natural Killer T-cell Dynamics in Human Immunodeficiency Virus-associated Tuberculosis

Background

Tuberculosis (TB) is the leading cause of mortality and morbidity in people living with human immunodeficiency virus (HIV) infection (PLWH). PLWH with TB disease are at risk of the paradoxical TB-associated immune reconstitution inflammatory syndrome (TB-IRIS) when they commence antiretroviral therapy. However, the pathophysiology is incompletely understood and specific therapy is lacking. We investigated the hypothesis that invariant natural killer T (iNKT) cells contribute to innate immune dysfunction associated with TB-IRIS.

Methods

In a cross-sectional study of 101 PLWH and HIV-uninfected South African patients with active TB and controls, iNKT cells were enumerated using α-galactosylceramide-loaded CD1d tetramers and subsequently functionally characterized by flow cytometry. In a second study of 49 people with HIV type 1 (HIV-1) and active TB commencing antiretroviral therapy, iNKT cells in TB-IRIS patients and non-IRIS controls were compared longitudinally.

Results

Circulating iNKT cells were reduced in HIV-1 infection, most significantly the CD4⁺ subset, which was inversely associated with HIV-1 viral load. iNKT cells in HIV-associated TB had increased surface CD107a expression, indicating cytotoxic degranulation. Relatively increased iNKT cell frequency in patients with HIV-1 infection and active TB was associated with development of TB-IRIS following antiretroviral therapy initiation. iNKT cells in TB-IRIS were CD4⁺CD8^– subset depleted and degranulated around the time of TB-IRIS onset.

Conclusions

Reduced iNKT cell CD4⁺ subsets as a result of HIV-1 infection may skew iNKT cell functionality toward cytotoxicity. Increased CD4^– cytotoxic iNKT cells may contribute to immunopathology in TB-IRIS.

Extrapulmonary tuberculosis among migrants in Europe, 1995 to 2017

Objectives

The proportion of tuberculosis (TB) cases occurring in migrants in Europe is increasing. Extrapulmonary TB poses challenges in diagnosis and treatment and causes serious morbidity and mortality, yet its extent in migrant populations is unclear. We assessed patterns of extrapulmonary TB in migrants across the European Union (EU)/European Free Trade Association (EFTA). We investigated the proportion of extrapulmonary TB cases among migrants versus non-migrants, and variations by specific site of disease, reporting European region, and migrant region of origin.

Methods

We carried out a cross-sectional secondary database analysis, utilizing 23 years of data collected between 1995 and 2017 from the European Surveillance System of the European Centre for Disease Prevention and Control for 32 EU/EFTA countries.

Results

In total, 1 270 896 TB cases were included, comprising 326 987 migrants (25.7%) and 943 909 non-migrants (74.3%). Of TB cases among migrants, 45.2% (n = 147 814) were extrapulmonary compared to 21.7% (n = 204 613) among non-migrants (p < 0.001). Lymphatic, bone/joint and peritoneal/digestive TB were more common among migrant than non-migrant extrapulmonary cases. A lower proportion of extrapulmonary TB was seen in Eastern Europe (17.4%, n = 98 656 of 566 170) and Southern Europe (29.6%, n = 62 481 of 210 828) compared with Western (35.7%, n = 89 498 of 250 517) and Northern Europe (41.8%, n = 101 792 of 243 381). Migrants from South-East Asia and Sub-Saharan Africa were at highest risk of extrapulmonary disease, with 62.0% (n = 55 401 of 89 353) and 54.5% (n = 38 327 of 70 378) of cases, respectively, being extrapulmonary.

Conclusions

Among TB cases in the EU/EFTA, extrapulmonary disease is significantly more common in migrants than in non-migrants. There is a need to improve clinical awareness of extrapulmonary TB and to integrate its detection into screening programmes.

Translating scientific discoveries during pandemics: ensuring equity for people affected by COVID-19 and tuberculosis

The coronavirus SARS-CoV-2 has reached almost every corner of the globe. Trillions of dollars are being invested in the COVID-19 pandemic response to support frontline clinical and public health efforts and spur rapid advances in scientific research. Concurrently, we are in the grip of a pandemic of greater longevity that receives scant public attention despite causing 4000 deaths each day [1]. It strikes disproportionately at the poor, treatment is unsatisfactory, and there is no effective vaccine with lasting immunity. This is tuberculosis (TB), another respiratory pathogen that has much in common with COVID-19. In contrast to COVID-19, citizens of rich countries do not feel threatened by TB, which has long been associated with poverty and is therefore not a strategic priority. The rise in isolationism, nationalism, xenophobia, and racism has had negative impacts on health policy that have impaired global and national responses to TB [2]. It is against these barriers that the global response to COVID-19 has also been struggling. Worryingly, early models predict that the COVID-19 pandemic may drive an additional 6.3 million TB cases and 1.3 million deaths by 2025 [3] and early data indicate interactions between these diseases [4, 5]. Despite the political rhetoric suggesting that “we are all in this together” when it comes to COVID-19, closer inspection through the lens of TB reminds us that when it comes to benefitting from scientific advances to improve health, we are not all equal.

The #COVID19 pandemic has emphasised major global health inequities: this editorial argues lessons learnt from TB must remind us of the gaps in the research agenda that must be addressed to ensure that scientific advances are equitably disseminatedhttps://bit.ly/3bTZHS3

Epidemic and pandemic viral infections: impact on tuberculosis and the lung: A consensus by the World Association for Infectious Diseases and Immunological Disorders (WAidid), Global Tuberculosis Network (GTN), and members of the European Society of Clinical Microbiology and Infectious Diseases Study Group for Mycobacterial Infections (ESGMYC)

Major epidemics, including some that qualify as pandemics, such as severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), HIV, influenza A (H1N1)pdm/09 and most recently COVID-19, affect the lung. Tuberculosis (TB) remains the top infectious disease killer, but apart from syndemic TB/HIV little is known regarding the interaction of viral epidemics and pandemics with TB. The aim of this consensus-based document is to describe the effects of viral infections resulting in epidemics and pandemics that affect the lung (MERS, SARS, HIV, influenza A (H1N1)pdm/09 and COVID-19) and their interactions with TB. A search of the scientific literature was performed. A writing committee of international experts including the European Centre for Disease Prevention and Control Public Health Emergency (ECDC PHE) team, the World Association for Infectious Diseases and Immunological Disorders (WAidid), the Global Tuberculosis Network (GTN), and members of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group for Mycobacterial Infections (ESGMYC) was established. Consensus was achieved after multiple rounds of revisions between the writing committee and a larger expert group. A Delphi process involving the core group of authors (excluding the ECDC PHE team) identified the areas requiring review/consensus, followed by a second round to refine the definitive consensus elements. The epidemiology and immunology of these viral infections and their interactions with TB are discussed with implications for diagnosis, treatment and prevention of airborne infections (infection control, viral containment and workplace safety). This consensus document represents a rapid and comprehensive summary on what is known on the topic.

Tuberculosis incidence among migrants according to migrant status: a cohort study, Denmark, 1993 to 2015

Background

Migrants account for the majority of tuberculosis (TB) cases in low-incidence countries in western Europe. TB incidence among migrants might be influenced by patterns of migration, but this is not well understood.

Aim

To investigate differences in TB risk across migrant groups according to migrant status and region of origin.

Methods

This prospective cohort study included migrants ≥ 18 years of age who obtained residency in Denmark between 1 January 1993 and 31 December 2015, matched 1:6 to Danish-born individuals. Migrants were grouped according to legal status of residency and region of origin. Incidence rates (IR) and incidence rate ratios (IRR) were estimated by Poisson regression.

Results

The cohort included 142,314 migrants. Migrants had significantly higher TB incidence (IR: 120/100,000 person-years (PY); 95% confidence interval (CI): 115–126) than Danish-born individuals (IR: 4/100,000 PY; 95% CI: 3–4). The IRR was significantly higher in all migrant groups compared with Danish-born (p < 0.01). A particularly higher risk was seen among family-reunified to refugees (IRR: 61.8; 95% CI: 52.7–72.4), quota refugees (IRR: 46.0; 95% CI: 36.6–57.6) and former asylum seekers (IRR: 45.3; 95% CI: 40.2–51.1), whereas lower risk was seen among family-reunified to Danish/Nordic citizens (IRR 15.8; 95% CI: 13.6–18.4) and family-reunified to immigrants (IRR: 16.9; 95% CI: 13.5–21.3).

Discussion

All migrants had higher TB risk compared with the Danish-born population. While screening programmes focus mostly on asylum seekers, other migrant groups with high risk of TB are missed. Awareness of TB risk in all high-risk groups should be strengthened and screening programmes should be optimised.

Extrapulmonary tuberculosis among migrants in the EU/EFTA: Implications for policy and practice

Background

The proportion of tuberculosis (TB) cases in the European Union/European Free Trade Association (EU/EFTA) that occur in migrants is increasing. Extrapulmonary TB poses challenges in diagnosis and treatment and causes serious morbidity and mortality. To date, there has been no in-depth exploration of extrapulmonary TB in migrants across Europe.

Methods

We analysed 22 years of data from the European Centre for Disease Prevention and Control's European Surveillance System (TESSy) for 32 EU/EFTA countries between 1995 and 2017. We investigated whether the proportion of TB cases that were extrapulmonary varied between migrants and non-migrants, and whether this varied by a) country/region of origin, b) reporting country/region, and c) site of disease.

Results

1,270,896 TB cases were included in the analysis, comprising 326,987 (25.7%) migrants, and 943,909 (74.3%) non-migrants. The proportion of TB that is extrapulmonary is significantly higher in migrants than in non-migrants: 45.2% (n = 147,814) of cases in migrants were extrapulmonary, compared to 21.7% (n = 204,613) in non-migrants (χ2=6.7x104, p &lt; 0.001). A relatively low proportion of extrapulmonary TB was seen in Eastern (17.4%) and Southern (29.6%) Europe compared with Western (35.7%) and Northern (41.8%) Europe, with migrants having a greater proportion of extrapulmonary TB only in Northern/Western Europe. Migrants from South-East Asia and Sub-Saharan Africa were at highest risk of extrapulmonary TB, with over half of all cases being extrapulmonary (62.0% and 54.5% respectively).

Conclusions

Among TB cases in the EU/EFTA, extrapulmonary disease is significantly more common in migrants than non-migrants, which has clinical and policy implications for patient detection and management. There is a need to improve clinical awareness of extrapulmonary TB, integrate detection of extrapulmonary TB into latent TB infection screening programmes, and harmonise data collection on migrant status in health systems.

Key messages

Migrants in the EU/EFTA are disproportionately affected by extrapulmonary TB compared to non-migrants. This has clinical and policy implications for diagnosis, screening, and data collection.

Antibiotic resistance patterns of Escherichia coli in migrants vs non-migrants: a study of 14 561 urine samples

BACKGROUND

To investigate the distribution of urine isolates and antibiotic resistance patterns in the predominant uropathogen Escherichia coli in migrant and non-migrant individuals.

METHODS

We linked a cohort consisting of all migrants obtaining residence as refugees or family-reunited migrants in Denmark between January 1993 and December 2015 to hospital urine samples examined from January 2000 to December 2015 at the Department of Microbiology, University Hospital Hvidovre, Denmark. Samples from non-migrant individuals, Danish-born from Danish parents, were included as comparison. Analysis was carried out using multivariate logistic regression.

RESULTS

There were 14 561 first-time urine samples included, with E. coli being the most prevalent bacterial pathogen. Of the identified isolates, 4686/11 737 were E. coli among non-migrants and 1032/2824 among migrants.Sulfamethoxazol-Trimethoprim (SXT) resistance was found in 34.3% (350/1020) of E. coli isolates among migrants and 23.2% (1070/4619) among non-migrant patients [odds ratio (OR) 1.73, 95% confidence interval (CI): 1.47-2.03]. Ciprofloxacin resistance was found in 5.8% (36/618) of isolates among migrants and 2.2% (67/3092) among non-migrants (OR 2.20, 95% CI: 1.37-3.53). Gentamicin (GEN) resistance was seen in 10.8% (61/565) and 4.7% (110/2328) of isolates (OR 2.33, 95% CI:1.63-3.34), Cefuroxime resistance in 8.5% (87/1019) and 3.4% (158/4618) (OR 2.40, 95% CI:1.77-3.24), Ampicillin (AMP) resistance in 51.4% and 40.8% (OR 1.65, 95% CI: 1.42-1.92) and Piperacillin-Tazobactam resistance in 6.9% (30/432) and 4.2% (65/1532) for migrant and non-migrant patients, respectively. When stratifying according to migrant status, family-reunited had higher odds of resistance than refugees for SXT, GEN and AMP.

CONCLUSIONS

Prevalence of antibiotic resistance was significantly higher in E. coli isolates among migrants, both refugees and family-reunited, than non-migrant patients. Differences could not be explained by comorbidity or income. The results emphasize the importance of urine sample testing in both local-born and migrants before antibiotic start-up and point to the benefit of considering migration to secure individual treatment and equal health outcomes.

Vaccination status of migrant populations in EU/EEA countries and implications for VPD control

Background

Migrant populations in the EU/EEA are increasingly being associated with outbreaks of vaccine-preventable diseases (VPDs), including the large-scale measles outbreak currently ongoing across Europe; however, it is unclear to what extent migrants represent an under-immunised group in the European context and implications for VPD control. Ensuring high levels of vaccination coverage is a key priority for all countries through the European Vaccine Action Plan, with EU/EEA Member States committed to eliminating measles and rubella, sustaining polio-free status, and controlling hepatitis B infection. We synthesised existing EU/EEA data to assess under-immunisation in migrants (defined as foreign born) residing in EU/EEA countries.

Methods

We did a systematic review and meta-analysis (PROSPERO CRD42018103666) in accordance with PRISMA guidelines. Inclusion criteria were primary research studies pertaining to vaccination status (measles, mumps, rubella, diphtheria, tetanus, pertussis, polio and Haemophilus influenzae type b [Hib]) in migrants residing in all EU/EEA countries. Pooled prevalence (95% CIs) were calculated for the meta-analysis using a random effects model.

Results

56 studies met our criteria (14 EU/EEA countries); 36 studies, which included data from 80,432 migrants, were included in the meta-analysis. Vaccination status of migrants for key VPDs varied substantially, with pooled immunisation coverage well below the herd immunity threshold (HIT) targets for measles 80% (95% CI: 73-87%; HIT 92-95%), mumps 65% (95% CI: 48-82%; HIT 75-86%), and diphtheria 51% (95% CI: 29-73%; HIT 83-86%). Polio type 1 and 2 coverage was high (97% [95% CI: 95-98%]; 95 [95% CI: 92-97%], respectively).

Conclusions

Migrants represent an under-immunised group in Europe, thus a high priority group for catch-up vaccination. Innovative strategies to engage them in vaccine uptake will be critical if we are to make European targets for the elimination and/or control of key VPDs.

Key messages

Migrants represent an under-immunised group in Europe and a high priority group for catch-up vaccination campaigns. Innovative strategies to engage them in vaccine uptake will be critical if we are to make European targets for the elimination and control of vaccine-preventable diseases.

Platelets Regulate Pulmonary Inflammation and Tissue Destruction in Tuberculosis

RATIONALE

Platelets may interact with the immune system in tuberculosis (TB) to regulate human inflammatory responses that lead to morbidity and spread of infection.

OBJECTIVES

To identify a functional role of platelets in the innate inflammatory and matrix-degrading response in TB.

METHODS

Markers of platelet activation were examined in plasma from 50 patients with TB before treatment and 50 control subjects. Twenty-five patients were followed longitudinally. Platelet-monocyte interactions were studied in a coculture model infected with live, virulent Mycobacterium tuberculosis (M.tb) and dissected using qRT-PCR, Luminex multiplex arrays, matrix degradation assays, and colony counts. Immunohistochemistry detected CD41 (cluster of differentiation 41) expression in a pulmonary TB murine model, and secreted platelet factors were measured in BAL fluid from 15 patients with TB and matched control subjects.

MEASUREMENTS AND MAIN RESULTS

Five of six platelet-associated mediators were upregulated in plasma of patients with TB compared with control subjects, with concentrations returning to baseline by Day 60 of treatment. Gene expression of the monocyte collagenase MMP-1 (matrix metalloproteinase-1) was upregulated by platelets in M.tb infection. Platelets also enhanced M.tb-induced MMP-1 and -10 secretion, which drove type I collagen degradation. Platelets increased monocyte IL-1 and IL-10 and decreased IL-12 and MDC (monocyte-derived chemokine; also known as CCL-22) secretion, as consistent with an M2 monocyte phenotype. Monocyte killing of intracellular M.tb was decreased. In the lung, platelets were detected in a TB mouse model, and secreted platelet mediators were upregulated in human BAL fluid and correlated with MMP and IL-1β concentrations.

CONCLUSIONS

Platelets drive a proinflammatory, tissue-degrading phenotype in TB.

The relative fitness of drug-resistant Mycobacterium tuberculosis: a modelling study of household transmission in Peru

The relative fitness of drug-resistant versus susceptible bacteria in an environment dictates resistance prevalence. Estimates for the relative fitness of resistant Mycobacterium tuberculosis (Mtb) strains are highly heterogeneous and mostly derived from in vitro experiments. Measuring fitness in the field allows us to determine how the environment influences the spread of resistance. We designed a household structured, stochastic mathematical model to estimate the fitness costs associated with multidrug resistance (MDR) carriage in Mtb in Lima, Peru during 2010–2013. By fitting the model to data from a large prospective cohort study of TB disease in household contacts, we estimated the fitness, relative to susceptible strains with a fitness of 1, of MDR-Mtb to be 0.32 (95% credible interval: 0.15–0.62) or 0.38 (0.24–0.61), if only transmission or progression to disease, respectively, was affected. The relative fitness of MDR-Mtb increased to 0.56 (0.42–0.72) when the fitness cost influenced both transmission and progression to disease equally. We found the average relative fitness of MDR-Mtb circulating within households in Lima, Peru during 2010–2013 to be significantly lower than concurrent susceptible Mtb. If these fitness levels do not change, then existing TB control programmes are likely to keep MDR-TB prevalence at current levels in Lima, Peru.

Occupational health outcomes among international migrant workers: a systematic review and meta-analysis

BACKGROUND

Globally, there are more than 150 million international migrant workers-individuals who are employed outside of their country of origin-comprising the largest international migrant group. A substantial number of migrants work in hazardous and exploitative environments, where they might be at considerable risk of injury and ill health. However, little data on occupational health outcomes of migrant workers exist, with which to inform global policy making and delivery of health services.

METHODS

For this systematic review and meta-analysis, we searched Embase, MEDLINE, Ovid Global Health, and PsychINFO databases for primary research published between Jan 1, 2008, and Jan 24, 2018, reporting occupational health outcomes among international migrant workers (defined as individuals who are or have been employed outside their country of origin), without language or geographical restrictions. We excluded studies containing mixed cohorts of migrants and native workers in which migrant data could not be disaggregated, and studies that did not explicitly report migrant status. The main outcome was prevalence of occupational health outcomes (defined as any injury, mortality, or physical or psychiatric morbidity due to an individual's work or workplace environment) among international migrant workers. Summary estimates were calculated using random-effects models. The study protocol has been registered with PROSPERO, number CRD42018099465.

FINDINGS

Of the 1218 studies identified by our search, 36 studies were included in our systematic review, and 18 studies were included in the meta-analysis. The systematic review included occupational health outcomes for 12 168 international migrant workers employed in 13 countries and territories, mostly employed in unskilled manual labour. Migrant workers originated from 25 low-income and middle-income countries, and worked in the following sectors: agriculture; domestic, retail, and service sectors; construction and trade; and manufacturing and processing. Migrant workers had various psychiatric and physical morbidities, and workplace accidents and injuries were relatively common. In the meta-analysis, among 7260 international migrant workers, the pooled prevalence of having at least one occupational morbidity was 47% (95% CI 29-64; I2=99·70%). Among 3890 migrant workers, the prevalence of having at least one injury or accident, including falls from heights, fractures and dislocations, ocular injuries, and cuts was 22% (7-37; I2=99·35%).

INTERPRETATION

International migrant workers are at considerable risk of work-related ill health and injury, and their health needs are critically overlooked in research and policy. Governments, policy makers, and businesses must enforce and improve occupational health and safety measures, which should be accompanied by accessible, affordable, and appropriate health care and insurance coverage to meet the care needs of this important working population.

FUNDING

Wellcome Trust.

Lesson of the month 1: A rare adverse reaction between flucloxacillin and paracetamol

Flucloxacillin, a beta-lactam antibiotic, is a commonly prescribed antibiotic for the treatment of infections caused by staphylococci and streptococci, most notably Staphylococcus aureus Paracetamol is one of the most dispensed medications by NHS England and is used for the treatment of fever and pain.1 However most doctors are unaware that concurrent use of these drugs can cause a potentially fatal drug interaction due to pyroglutamic acidosis (PGA), also known as 5-oxoprolinaemia. PGA is a rare cause of raised anion gap metabolic acidosis due to disruption of the γ-glutamyl cycle. We report the case of a patient with multiple comorbidities who developed PGA due to coadministration of paracetamol and flucloxacillin.

National approaches to the vaccination of recently arrived migrants in Europe: A comparative policy analysis across 32 European countries

BACKGROUND

Migrants may be underimmunised and at higher risk of vaccine-preventable diseases, yet there has been no comprehensive examination of what policies are currently implemented across Europe targeting child and adult migrants. We analysed vaccination policies for migrants in 32 EU/EEA countries and Switzerland.

METHODS

Using framework analysis, we did a comparative analysis of national policies and guidelines pertaining to vaccination in recently arrived migrants through a systematic guideline and literature review and by approaching national experts.

RESULTS

Six (18.8%) of 32 countries had comprehensive policies specific to the vaccination of migrants (two focused only on child migrants, four on both adults and children). Nineteen (59.4%) countries applied their national vaccination schedule for migrant vaccinations, predominantly focusing on children; and five (15.6%) countries had circulated additional migrant-specific resources to relevant health-care providers. In six (18.8%) countries, policies on migrant vaccination focused on outbreak-specific vaccines only. In ten (31.3%) countries, policies focused on priority vaccinations, with polio being the vaccine most commonly administered and heterogeneity noted in vaccines recommended to adults, adolescents, and children. Eighteen (56.3%) countries recommended that an individual should be considered as unvaccinated where vaccination records were missing, and vaccines re-administered. Nine (28.1%) countries reported that specific vaccinations were mandatory.

CONCLUSION

There is considerable variation in policies across Europe regarding approaches to vaccination in adult and child migrants, and a lack of clarity on optimum ways forward, what vaccines to offer, with a need for robust research in this area. More emphasis must be placed on ensuring migrant-specific guidance is disseminated to front-line healthcare professionals to improve vaccine delivery and uptake in diverse migration populations across the region.

Global patterns of mortality in international migrants: a systematic review and meta-analysis

BACKGROUND

258 million people reside outside their country of birth; however, to date no global systematic reviews or meta-analyses of mortality data for these international migrants have been done. We aimed to review and synthesise available mortality data on international migrants.

METHODS

In this systematic review and meta-analysis, we searched MEDLINE, Embase, the Cochrane Library, and Google Scholar databases for observational studies, systematic reviews, and randomised controlled trials published between Jan 1, 2001, and March 31, 2017, without language restrictions. We included studies reporting mortality outcomes for international migrants of any age residing outside their country of birth. Studies that recruited participants exclusively from intensive care or high dependency hospital units, with an existing health condition or status, or a particular health exposure were excluded. We also excluded studies limited to maternal or perinatal outcomes. We screened studies using systematic review software and extracted data from published reports. The main outcomes were all-cause and International Classification of Diseases, tenth revision (ICD-10) cause-specific standardised mortality ratios (SMRs) and absolute mortality rates. We calculated summary estimates using random-effects models. This study is registered with PROSPERO, number CRD42017073608.

FINDINGS

Of the 12 480 articles identified by our search, 96 studies were eligible for inclusion. The studies were geographically diverse and included data from all global regions and for 92 countries. 5464 mortality estimates for more than 15·2 million migrants were included, of which 5327 (97%) were from high-income countries, 115 (2%) were from middle-income countries, and 22 (<1%) were from low-income countries. Few studies included mortality estimates for refugees (110 estimates), asylum seekers (144 estimates), or labour migrants (six estimates). The summary estimate of all-cause SMR for international migrants was lower than one when compared with the general population in destination countries (0·70 [95% CI 0·65-0·76]; I2=99·8%). All-cause SMR was lower in both male migrants (0·72 [0·63-0·81]; I2=99·8%) and female migrants (0·75 [0·67-0·84]; I2=99·8%) compared with the general population. A mortality advantage was evident for refugees (SMR 0·50 [0·46-0·54]; I2=89·8%), but not for asylum seekers (1·05 [0·89-1·24]; I2=54·4%), although limited data was available on these groups. SMRs for all causes of death were lower in migrants compared with the general populations in the destination country across all 13 ICD-10 categories analysed, with the exception of infectious diseases and external causes. Heterogeneity was high across the majority of analyses. Point estimates of all-cause age-standardised mortality in migrants ranged from 420 to 874 per 100 000 population.

INTERPRETATION

Our study showed that international migrants have a mortality advantage compared with general populations, and that this advantage persisted across the majority of ICD-10 disease categories. The mortality advantage identified will be representative of international migrants in high-income countries who are studying, working, or have joined family members in these countries. However, our results might not reflect the health outcomes of more marginalised groups in low-income and middle-income countries because little data were available for these groups, highlighting an important gap in existing research. Our results present an opportunity to reframe the public discourse on international migration and health in high-income countries.

FUNDING

Wellcome Trust, National Institute for Health Research, Medical Research Council, Alliance for Health Policy and Systems Research, Department for International Development, Fogarty International Center, Grand Challenges Canada, International Development Research Centre Canada, Inter-American Institute for Global Change Research, National Cancer Institute, National Heart, Lung and Blood Institute, National Institute of Mental Health, Swiss National Science Foundation, World Diabetes Foundation, UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, and European Society for Clinical Microbiology and Infectious Diseases (ESCMID) Study Group Research Funding for the ESCMID Study Group for Infections in Travellers and Migrants.

Divergent approaches in the vaccination of recently arrived migrants to Europe: a survey of national experts from 32 countries, 2017

BackgroundMigrants within the European Union and European Economic Area (EU/EEA) may be underimmunised and lack documentation on previous vaccinations. We investigated approaches to vaccination in recently arrived adult and child migrants, and guideline availability and implementation. Methods: Between March and May 2017, a national vaccination expert from every EU/EEA country and Switzerland completed an electronic questionnaire. We used descriptive analyses to calculate percentages, and framework analysis to synthesise free-text responses. Results: We approached 32 countries (response rate 100%). Although 28 experts reported vaccination guidance at national level, specific guidelines for recently arrived migrants were only available in six countries and not consistently implemented. Twenty-three countries administered vaccinations during on-arrival health checks. Most experts recommended multiple vaccination opportunities be made available: at point of entry (n = 13) or at holding level (reception centres, migrant camps, detention centres) (n = 21). In 30 countries, child migrants without evidence of previous vaccination were re-vaccinated according to the national schedule. Diphtheria-pertussis-tetanus and polio vaccinations were given to migrant children in all countries, measles-mumps-rubella (MMR) in 31 countries, hepatitis B vaccination in 25. Low levels of catch-up vaccination were reported in adult migrants, with only 13 countries offering MMR and 10 countries charging fees. Conclusion: Existing guidance is often not migrant-specific and may not be applied in practice; clarification is needed on which vaccines should be given. Strategies are needed specifically for catch-up vaccination in adult migrants. Vaccinations should be offered in multiple settings, free of charge, with sufficient guidance and training provided to front-line healthcare professionals.

Author Correction: Matrix metalloproteinase-9 activity and a downregulated Hedgehog pathway impair blood-brain barrier function in an in vitro model of CNS tuberculosis

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND

Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings.

METHODS

For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681.

FINDINGS

We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations.

INTERPRETATION

Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration.

FUNDING

UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London.

Integrin α2β1 Expression Regulates Matrix Metalloproteinase-1-Dependent Bronchial Epithelial Repair in Pulmonary Tuberculosis

Pulmonary tuberculosis (TB) is caused by inhalation of Mycobacterium tuberculosis, which damages the bronchial epithelial barrier to establish local infection. Matrix metalloproteinase-1 plays a crucial role in the immunopathology of TB, causing breakdown of type I collagen and cavitation, but this collagenase is also potentially involved in bronchial epithelial repair. We hypothesized that the extracellular matrix (ECM) modulates M. tuberculosis-driven matrix metalloproteinase-1 expression by human bronchial epithelial cells (HBECs), regulating respiratory epithelial cell migration and repair. Medium from monocytes stimulated with M. tuberculosis induced collagenase activity in bronchial epithelial cells, which was reduced by ~87% when cells were cultured on a type I collagen matrix. Matrix metalloproteinase-1 had a focal localization, which is consistent with cell migration, and overall secretion decreased by 32% on type I collagen. There were no associated changes in the specific tissue inhibitors of metalloproteinases. Decreased matrix metalloproteinase-1 secretion was due to ligand-binding to the α2β1 integrin and was dependent on the actin cytoskeleton. In lung biopsies, samples from patients with pulmonary TB, integrin α2β1 is highly expressed on the bronchial epithelium. Areas of lung with disrupted collagen matrix showed an increase in matrix metalloproteinases-1 expression compared with areas where collagen was comparable to control lung. Type I collagen matrix increased respiratory epithelial cell migration in a wound-healing assay, and this too was matrix metalloproteinase-dependent, since it was blocked by the matrix metalloproteinase inhibitor GM6001. In summary, we report a novel mechanism by which α2β1-mediated signals from the ECM modulate matrix metalloproteinase-1 secretion by HBECs, regulating their migration and epithelial repair in TB.

Cough Frequency During Treatment Associated With Baseline Cavitary Volume and Proximity to the Airway in Pulmonary TB

BACKGROUND

Cough frequency, and its duration, is a biomarker that can be used in low-resource settings without the need of laboratory culture and has been associated with transmission and treatment response. Radiologic characteristics associated with increased cough frequency may be important in understanding transmission. The relationship between cough frequency and cavitary lung disease has not been studied.

METHODS

We analyzed data in 41 adults who were HIV negative and had culture-confirmed, drug-susceptible pulmonary TB throughout treatment. Cough recordings were based on the Cayetano Cough Monitor, and sputum samples were evaluated using microscopic observation drug susceptibility broth culture; among culture-positive samples, bacillary burden was assessed by means of time to positivity. CT scans were analyzed by a US-board-certified radiologist and a computer-automated algorithm. The algorithm evaluated cavity volume and cavitary proximity to the airway. CT scans were obtained within 1 month of treatment initiation. We compared small cavities (≤ 7 mL) and large cavities (> 7 mL) and cavities located closer to (≤ 10 mm) and farther from (> 10 mm) the airway to cough frequency and cough cessation until treatment day 60.

RESULTS

Cough frequency during treatment was twofold higher in participants with large cavity volumes (rate ratio [RR], 1.98; P = .01) and cavities located closer to the airway (RR, 2.44; P = .001). Comparably, cough ceased three times faster in participants with smaller cavities (adjusted hazard ratio [HR], 2.89; P = .06) and those farther from the airway (adjusted HR, 3.61;, P = .02). Similar results were found for bacillary burden and culture conversion during treatment.

CONCLUSIONS

Cough frequency during treatment is greater and lasts longer in patients with larger cavities, especially those closer to the airway.

Exhaled Nitric Oxide is Not a Biomarker for Pulmonary Tuberculosis

To reduce transmission of tuberculosis (TB) in resource-limited countries where TB remains a major cause of mortality, novel diagnostic tools are urgently needed. We evaluated the fractional concentration of exhaled nitric oxide (FeNO) as an easily measured, noninvasive potential biomarker for diagnosis and monitoring of treatment response in participants with pulmonary TB including multidrug resistant–TB in Lima, Peru. In a longitudinal study however, we found no differences in baseline median FeNO levels between 38 TB participants and 93 age-matched controls (13 parts per billion [ppb] [interquartile range (IQR) = 8–26] versus 15 ppb [IQR = 12–24]), and there was no change over 60 days of treatment (15 ppb [IQR = 10–19] at day 60). Taking this and previous evidence together, we conclude FeNO is not of value in either the diagnosis of pulmonary TB or as a marker of treatment response.

Vaccination status and needs of asylum-seeking children in Denmark: a retrospective data analysis

Objectives

Asylum seekers to Europe may come from war-torn countries where health systems have broken down, and there is evidence that asylum-seeking children have low coverage of childhood vaccinations, as well as uptake of immunisations in host countries. Such gaps in immunisation have important implications for effective national vaccination programmes. How we approach vaccination in children and adults entering Western Europe, where as a group they face barriers to health services and screening, is a growing debate; however, there are limited data on the vaccination status of these hard-to-reach communities, and robust evidence is needed to inform immunisation strategies. The aim of this study was to explore the vaccination status and needs of asylum-seeking children and adolescents in Denmark.

Study design

We conducted a retrospective data analysis of anonymised patient records for asylum-seeking children and adolescents extracted from the Danish Red Cross database.

Methods

We retrospectively searched the Danish Red Cross database for children and adolescents (aged 3 months–17 years) with active asylum applications in Denmark as of October 28, 2015. Data were extracted for demographic characteristics, vaccination status and vaccinations needed by asylum-seeking children presenting to Red Cross asylum centres for routine statutory health screening.

Results

We explored the vaccination status and needs of 2126 asylum-seeking children and adolescents. About 64% of the study population were male and 36% were female. Eight nationalities were represented, where 33% of the total of children and adolescents were not immunised in accordance with Danish national guidelines, while 7% were considered partly vaccinated, and 60% were considered adequately vaccinated. Afghan (57% not vaccinated/unknown) and Eritrean (54% not vaccinated/unknown) children were the least likely to be vaccinated of all nationalities represented, as were boys (37% not vaccinated/unknown) compared with girls (27% not vaccinated/unknown) and children and adolescents aged between 12 and 17 years (48% not vaccinated/unknown) compared with 6- to 11-year olds (26%) and 0- to 5-year olds (22%). The health screenings resulted in 1328 vaccinations. The most commonly needed vaccines were diphtheria, tetanus, pertussis, polio and Haemophilus influenzae type b, (DTaP/IPV/Hib) which comprised 49% of the vaccines distributed, followed by the pneumococcal vaccine (Prevnar) (28%) and measles, mumps and rubella (MMR) vaccine (23%).

Conclusions

The finding that nearly one-third of asylum-seeking children and adolescents in Denmark were in need of further vaccinations highlights the gaps in immunisation coverage in these populations. These results point to the need to improve access to health services and promote national vaccine programmes targeted at these communities to facilitate vaccination uptake and increase immunisation coverage to reduce the risk of preventable infectious diseases among asylum-seeking children.

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Little is known on the state of immunisation of refugees arriving in Western receiving countries.

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Variations in status on arrival to Denmark were associated with gender, country of origin and age groups.

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Vaccination needs were found to be associated with country of origin, while gender did not act as a significant determinant.

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Immunisations for vaccine-preventable diseases is critical for protecting refugee health and host communities.

Interleukin-17 regulates matrix metalloproteinase activity in human pulmonary tuberculosis

Tuberculosis (TB) is characterized by extensive pulmonary matrix breakdown. Interleukin-17 (IL-17) is key in host defence in TB but its role in TB-driven tissue damage is unknown. We investigated the hypothesis that respiratory stromal cell matrix metalloproteinase (MMP) production in TB is regulated by T-helper 17 (TH -17) cytokines. Biopsies of patients with pulmonary TB were analysed by immunohistochemistry (IHC), and patient bronchoalveolar lavage fluid (BALF) MMP and cytokine concentrations were measured by Luminex assays. Primary human airway epithelial cells were stimulated with conditioned medium from human monocytes infected with Mycobacterium tuberculosis (Mtb) and TH -17 cytokines. MMP secretion, activity, and gene expression were determined by ELISA, Luminex assay, zymography, RT-qPCR, and dual luciferase reporter assays. Signalling pathways were examined using phospho-western analysis and siRNA. IL-17 is expressed in TB patient granulomas and MMP-3 is expressed in adjacent pulmonary epithelial cells. IL-17 had a divergent, concentration-dependent effect on MMP secretion, increasing epithelial secretion of MMP-3 (p < 0.001) over 72 h, whilst decreasing that of MMP-9 (p < 0.0001); mRNA levels were similarly affected. Both IL-17 and IL-22 increased fibroblast Mtb-dependent MMP-3 secretion but IL-22 did not modulate epithelial MMP-3 expression. Both IL-17 and IL-22, but not IL-23, were significantly up-regulated in BALF from TB patients. IL-17-driven MMP-3 was dependent on p38 MAP kinase and the PI3K p110α subunit. In summary, IL-17 drives airway stromal cell-derived MMP-3, a mediator of tissue destruction in TB, alone and with monocyte-dependent networks in TB. This is regulated by p38 MAP kinase and PI3K pathways. © 2017 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Multidrug-resistant tuberculosis treatment adherence in migrants: a systematic review and meta-analysis

BACKGROUND

Multidrug-resistant tuberculosis (MDR-TB) is a growing concern in meeting global targets for TB control. In high-income low-TB-incidence countries, a disproportionate number of MDR-TB cases occur in migrant (foreign-born) populations, with concerns about low adherence rates in these patients compared to the host non-migrant population. Tackling MDR-TB in this context may, therefore, require unique approaches. We conducted a systematic review and meta-analysis to identify and synthesise data on MDR-TB treatment adherence in migrant patients to inform evidence-based strategies to improve care pathways and health outcomes in this group.

METHODS

This systematic review and meta-analysis was conducted in line with PRISMA guidelines (PROSPERO 42017070756). The databases Embase, MEDLINE, Global Health and PubMed were searched to 24 May 2017 for primary research reporting MDR-TB treatment adherence and outcomes in migrant populations, with no restrictions on dates or language. A meta-analysis was conducted using random-effects models.

RESULTS

From 413 papers identified in the database search, 15 studies reporting on MDR-TB treatment outcomes for 258 migrants and 174 non-migrants were included in the systematic review and meta-analysis. The estimated rate of adherence to MDR-TB treatment across migrant patients was 71% [95% confidence interval (CI) = 58-84%], with non-adherence reported among 20% (95% CI = 4-37%) of migrant patients. A key finding was that there were no differences in estimated rates of adherence [risk ratio (RR) = 1.05; 95% CI = 0.82-1.34] or non-adherence (RR = 0.97; 95% CI = 0.79-1.36) between migrants and non-migrants.

CONCLUSIONS

MDR-TB treatment adherence rates among migrants in high-income low-TB-incidence countries are approaching global targets for treatment success (75%), and are comparable to rates in non-migrants. The findings highlight that only just over 70% of migrant and non-migrant patients adhere to MDR-TB treatment. The results point to the importance of increasing adherence in all patient groups, including migrants, with an emphasis on tailoring care based on social risk factors for poor adherence. We believe that MDR-TB treatment targets are not ambitious enough.

Histological Examination in Obtaining a Diagnosis in Patients with Lymphadenopathy in Lima, Peru

The differential diagnosis for lymphadenopathy is wide and clinical presentations overlap, making obtaining an accurate diagnosis challenging. We sought to characterize the clinical and radiological characteristics, histological findings, and diagnoses for a cohort of patients with lymphadenopathy of unknown etiology. 121 Peruvian adults with lymphadenopathy underwent lymph node biopsy for microbiological and histopathological evaluation. Mean patient age was 41 years (Interquartile Range 26–52), 56% were males, and 39% were HIV positive. Patients reported fever (31%), weight loss (23%), and headache (22%); HIV infection was associated with fever (P < 0.05) and gastrointestinal symptoms (P < 0.05). Abnormalities were reported in 40% of chest X-rays (N = 101). Physicians suspected TB in 92 patients (76%), lymphoma in 19 patients (16%), and other malignancy in seven patients (5.8%). Histological diagnoses (N = 117) included tuberculosis (34%), hyperplasia (27%), lymphoma (13%), and nonlymphoma malignancy (14%). Hyperplasia was more common (P < 0.001) and lymphoma less common (P = 0.005) among HIV-positive than HIV-negative patients. There was a trend toward reduced frequency of caseous necrosis in samples from HIV-positive than HIV-negative TB patients (67 versus 93%, P = 0.055). The spectrum of diagnoses was broad, and clinical and radiological features correlated poorly with diagnosis. On the basis of clinical features, physicians over-diagnosed TB, and under-diagnosed malignancy. Although this may not be inappropriate in resource-limited settings where TB is the most frequent easily treatable cause of lymphadenopathy, diagnostic delays can be detrimental to patients with malignancy. It is important that patients with lymphadenopathy undergo a full diagnostic work-up including sampling for histological evaluation to obtain an accurate diagnosis.

A score to predict and stratify risk of tuberculosis in adult contacts of tuberculosis index cases: a prospective derivation and external validation cohort study

BACKGROUND

Contacts of tuberculosis index cases are at increased risk of developing tuberculosis. Screening, preventive therapy, and surveillance for tuberculosis are underused interventions in contacts, particularly adults. We developed a score to predict risk of tuberculosis in adult contacts of tuberculosis index cases.

METHODS

In 2002-06, we recruited contacts aged 15 years or older of index cases with pulmonary tuberculosis who lived in desert shanty towns in Ventanilla, Peru. We followed up contacts for tuberculosis until February, 2016. We used a Cox proportional hazards model to identify index case, contact, and household risk factors for tuberculosis from which to derive a score and classify contacts as low, medium, or high risk. We validated the score in an urban community recruited in Callao, Peru, in 2014-15.

FINDINGS

In the derivation cohort, we identified 2017 contacts of 715 index cases, and median follow-up was 10·7 years (IQR 9·5-11·8). 178 (9%) of 2017 contacts developed tuberculosis during 19 147 person-years of follow-up (incidence 0·93 per 100 person-years, 95% CI 0·80-1·08). Risk factors for tuberculosis were body-mass index, previous tuberculosis, age, sustained exposure to the index case, the index case being in a male patient, lower community household socioeconomic position, indoor air pollution, previous tuberculosis among household members, and living in a household with a low number of windows per room. The 10-year risks of tuberculosis in the low-risk, medium-risk, and high-risk groups were, respectively, 2·8% (95% CI 1·7-4·4), 6·2% (4·8-8·1), and 20·6% (17·3-24·4). The 535 (27%) contacts classified as high risk accounted for 60% of the tuberculosis identified during follow-up. The score predicted tuberculosis independently of tuberculin skin test and index-case drug sensitivity results. In the external validation cohort, 65 (3%) of 1910 contacts developed tuberculosis during 3771 person-years of follow-up (incidence 1·7 per 100 person-years, 95% CI 1·4-2·2). The 2·5-year risks of tuberculosis in the low-risk, medium-risk, and high-risk groups were, respectively, 1·4% (95% CI 0·7-2·8), 3·9% (2·5-5·9), and 8·6%· (5·9-12·6).

INTERPRETATION

Our externally validated risk score could predict and stratify 10-year risk of developing tuberculosis in adult contacts, and could be used to prioritise tuberculosis control interventions for people most likely to benefit.

FUNDING

Wellcome Trust, Department for International Development Civil Society Challenge Fund, Joint Global Health Trials consortium, Bill & Melinda Gates Foundation, Imperial College National Institutes of Health Research Biomedical Research Centre, Foundation for Innovative New Diagnostics, Sir Halley Stewart Trust, WHO, TB REACH, and Innovation for Health and Development.

Matrix Degradation in Human Immunodeficiency Virus Type 1-Associated Tuberculosis and Tuberculosis Immune Reconstitution Inflammatory Syndrome: A Prospective Observational Study

Background

Extensive immunopathology occurs in human immunodeficiency virus (HIV)/tuberculosis (TB) coinfection, but the underlying molecular mechanisms are not well-defined. Excessive matrix metalloproteinase (MMP) activity is emerging as a key process but has not been systematically studied in HIV-associated TB.

Methods

We performed a cross-sectional study of matrix turnover in HIV type 1 (HIV-1)-infected and -uninfected TB patients and controls, and a prospective cohort study of HIV-1-infected TB patients at risk of TB immune reconstitution inflammatory syndrome (TB-IRIS), in Cape Town, South Africa. Sputum and plasma MMP concentrations were quantified by Luminex, plasma procollagen III N-terminal propeptide (PIIINP) by enzyme-linked immunosorbent assay, and urinary lipoarabinomannan (LAM) by Alere Determine TB LAM assay. Peripheral blood mononuclear cells from healthy donors were cultured with Mycobacterium tuberculosis and extracellular matrix in a 3D model of TB granuloma formation.

Results

MMP activity differed between HIV-1-infected and -uninfected TB patients and corresponded with specific TB clinical phenotypes. HIV-1-infected TB patients had reduced pulmonary MMP concentrations, associated with reduced cavitation, but increased plasma PIIINP, compared to HIV-1-uninfected TB patients. Elevated extrapulmonary extracellular matrix turnover was associated with TB-IRIS, both before and during TB-IRIS onset. The predominant collagenase was MMP-8, which was likely neutrophil derived and M. tuberculosis-antigen driven. Mycobacterium tuberculosis-induced matrix degradation was suppressed by the MMP inhibitor doxycycline in vitro.

Conclusions

MMP activity in TB differs by HIV-1 status and compartment, and releases matrix degradation products. Matrix turnover in HIV-1-infected patients is increased before and during TB-IRIS, informing novel diagnostic strategies. MMP inhibition is a potential host-directed therapy strategy for prevention and treatment of TB-IRIS.

Early Secretory Antigenic Target-6 Drives Matrix Metalloproteinase-10 Gene Expression and Secretion in Tuberculosis

Tuberculosis (TB) causes disease worldwide, and multidrug resistance is an increasing problem. Matrix metalloproteinases (MMPs), particularly the collagenase MMP-1, cause lung extracellular matrix destruction, which drives disease transmission and morbidity. The role in such tissue damage of the stromelysin MMP-10, a key activator of the collagenase MMP-1, was investigated in direct Mycobacterium tuberculosis (Mtb)-infected macrophages and in conditioned medium from Mtb-infected monocyte-stimulated cells. Mtb infection increased MMP-10 secretion from primary human macrophages 29-fold, whereas Mtb-infected monocytes increased secretion by 4.5-fold from pulmonary epithelial cells and 10.5-fold from fibroblasts. Inhibition of MMP-10 activity decreased collagen breakdown. In two independent cohorts of patients with TB from different continents, MMP-10 was increased in both induced sputum and bronchoalveolar lavage fluid compared with control subjects and patients with other respiratory diseases (both P < 0.05). Mtb drove 3.5-fold greater MMP-10 secretion from human macrophages than the vaccine strain bacillus Calmette-Guerin (P < 0.001), whereas both mycobacteria up-regulated TNF-α secretion equally. Using overlapping, short, linear peptides covering the sequence of early secretory antigenic target-6, a virulence factor secreted by Mtb, but not bacillus Calmette-Guerin, we found that stimulation of human macrophages with a single specific 15-amino acid peptide sequence drove threefold greater MMP-10 secretion than any other peptide (P < 0.001). Mtb-driven MMP-10 secretion was inhibited in a dose-dependent manner by p38 and extracellular signal-related kinase mitogen-activated protein kinase blockade (P < 0.001 and P < 0.01 respectively), but it was not affected by inhibition of NF-κB. In summary, Mtb activates inflammatory and stromal cells to secrete MMP-10, and this is partly driven by the virulence factor early secretory antigenic target-6, implicating it in TB-associated tissue destruction.

Monocyte Adhesion, Migration, and Extracellular Matrix Breakdown Are Regulated by Integrin αVβ3 in Mycobacterium tuberculosis Infection

In tuberculosis (TB), the innate inflammatory immune response drives tissue destruction, morbidity, and mortality. Monocytes secrete matrix metalloproteinases (MMPs), which have key roles in local tissue destruction and cavitation. We hypothesized that integrin signaling might regulate monocyte MMP secretion in pulmonary TB during cell adhesion to the extracellular matrix (ECM). Adhesion to type I collagen and fibronectin by Mycobacterium tuberculosis-stimulated monocytes increased MMP-1 gene expression by 2.6-fold and 4.3-fold respectively, and secretion by 60% (from 1208.1 ± 186 to 1934.4 ± 135 pg/ml; p < 0.0001) and 63% (1970.3 ± 95 pg/ml; p < 0.001). MMP-10 secretion increased by 90% with binding to type I collagen and 55% with fibronectin, whereas MMP-7 increased 57% with collagen. The ECM did not affect the secretion of tissue inhibitors of metalloproteinases-1 or -2. Integrin αVβ3 surface expression was specifically upregulated in stimulated monocytes and was further increased after adhesion to type I collagen. Binding of either β3 or αV integrin subunits increased MMP-1/10 secretion in M. tuberculosis-stimulated monocytes. In a cohort of TB patients, significantly increased integrin β3 mRNA accumulation in induced sputum was detected, to our knowledge, for the first time, compared with control subjects (p < 0.05). Integrin αVβ3 colocalized with areas of increased and functionally active MMP-1 on infected monocytes, and αVβ3 blockade markedly decreased type I collagen breakdown, and impaired both monocyte adhesion and leukocyte migration in a transwell system (p < 0.0001). In summary, our data demonstrate that M. tuberculosis stimulation upregulates integrin αVβ3 expression on monocytes, which upregulates secretion of MMP-1 and -10 on adhesion to the ECM. This leads to increased monocyte recruitment and collagenase activity, which will drive inflammatory tissue damage.