Diagnosis of opportunistic infections: HIV co-infections - tuberculosis

Development of a Multiplex HIV/TB Diagnostic Assay Based on the Microarray Technology

Currently there are diagnostic tests available for human immunodeficiency virus (HIV) and tuberculosis (TB); however, they are still diagnosed separately, which can delay treatment in cases of co-infection. Here we report on a multiplex microarray technology for the detection of HIV and TB antibodies using p24 as well as TB CFP10, ESAT6 and pstS1 antigens on epoxy-silane slides. To test this technology for antigen-antibody interactions, immobilized antigens were exposed to human sera spiked with physiological concentrations of primary antibodies, followed by secondary antibodies conjugated to a fluorescent reporter. HIV and TB antibodies were captured with no cross-reactivity observed. The sensitivity of the slides was compared to that of high-binding plates. We found that the slides were more sensitive, with the detection limit being 0.000954 µg/mL compared to 4.637 µg/mL for the plates. Furthermore, stability studies revealed that the immobilized antigens could be stored dry for at least 90 days and remained stable across all pH and temperatures assessed, with pH 7.4 and 25 °C being optimal. The data collectively suggested that the HIV/TB multiplex detection technology we developed has the potential for use to diagnose HIV and TB co-infection, and thus can be developed further for the purpose.

Evaluation of the IP-10 mRNA release assay for diagnosis of TB in HIV-infected individuals

HIV-infected individuals are susceptible to Mycobacterium tuberculosis (M.tb) infection and are at high risk of developing active tuberculosis (TB). Interferon-gamma release assays (IGRAs) are auxiliary tools in the diagnosis of TB. However, the performance of IGRAs in HIV-infected individuals is suboptimal, which limits clinical application. Interferon-inducible protein 10 (IP-10) is an alternative biomarker for identifying M.tb infection due to its high expression after stimulation with M.tb antigens. However, whether IP-10 mRNA constitutes a target for the diagnosis of TB in HIV-infected individuals is unknown. Thus, we prospectively enrolled HIV-infected patients with suspected active TB from five hospitals between May 2021 and May 2022, and performed the IGRA test (QFT-GIT) alongside the IP-10 mRNA release assay on peripheral blood. Of the 216 participants, 152 TB patients and 48 non-TB patients with a conclusive diagnosis were included in the final analysis. The number of indeterminate results of IP-10 mRNA release assay (13/200, 6.5%) was significantly lower than that of the QFT-GIT test (42/200, 21.0%) (P = 0.000026). IP-10 mRNA release assay had a sensitivity of 65.3% (95%CI 55.9% - 73.8%) and a specificity of 74.2% (95%CI 55.4% - 88.1%), respectively; while the QFT-GIT test had a sensitivity of 43.2% (95%CI 34.1% - 52.7%) and a specificity of 87.1% (95%CI 70.2% - 96.4%), respectively. The sensitivity of the IP-10 mRNA release assay was significantly higher than that of QFT-GIT test (P = 0.00062), while no significant difference was detected between the specificities of these two tests (P = 0.198). The IP-10 mRNA release assay showed a lower dependence on CD4⁺ T cells than that of QFT-GIT test. This was evidenced by the fact that the QFT-GIT test had a higher number of indeterminate results and a lower sensitivity when the CD4⁺ T cells counts were decreased (P < 0.05), while no significant difference in the number of indeterminate results and sensitivity were observed for the IP-10 mRNA release assay among HIV-infected individuals with varied CD4⁺T cells counts (P > 0.05). Therefore, our study suggested that M.tb specific IP-10 mRNA is a better biomarker for diagnosis of TB in HIV-infected individuals.

Dysregulation of the IFN-I signaling pathway by Mycobacterium tuberculosis leads to exacerbation of HIV-1 infection of macrophages

While tuberculosis (TB) is a risk factor in HIV-1-infected individuals, the mechanisms by which Mycobacterium tuberculosis (Mtb), the agent of TB in humans, worsens HIV-1 pathogenesis still need to be fully elucidated. Recently, we showed that HIV-1 infection and spread are exacerbated in macrophages exposed to TB-associated microenvironments. Transcriptomic analysis of macrophages conditioned with medium of Mtb-infected human macrophages (cmMTB) revealed an up-regulation of the typeI interferon (IFN-I) pathway, characterized by the overexpression of IFN-inducible genes. Historically, IFN-I are well known for their antiviral functions, but our previous work showed that this is not the case in the context of coinfection with HIV-1. Here, we show that the IFN-I response signature in cmMTB-treated macrophages matches the one observed in the blood of active TB patients, and depends on the timing of incubation with cmMTB. This suggests that the timing of macrophage's exposure to IFN-I can impact their capacity to control HIV-1 infection. Strikingly, we found that cmMTB-treated macrophages are hyporesponsive to extrastimulation with exogenous IFN-I, used to mimic HIV-1 infection. Yet, depleting STAT1 by gene silencing to block the IFN-I signaling pathway reduced TB-induced exacerbation of HIV-1 infection. Altogether, by aiming to understand why TB-derived IFN-I preexposure of macrophages did not induce antiviral immunity against HIV-1, we demonstrated that these cells are hyporesponsive to exogenous IFN-I, a phenomenon that prevents macrophage activation against HIV-1.

The Performance of Metagenomic Next-Generation Sequence in the Diagnosis of Suspected Opportunistic Infections in Patients with Acquired Immunodeficiency Syndrome

Background

For acquired immunodeficiency syndrome (AIDS) patients with suspected opportunistic infections, the rapid and accurate identification of pathogens remains a challenge. Metagenomic next-generation sequencing (mNGS) has emerged as a pan-pathogen assay for infectious diseases diagnosis, but its guiding significance for diagnosis and antimicrobials treatment in AIDS patients with suspected opportunistic infections is still not well established. In this study, we compared the microbiological diagnostic value of mNGS with that of conventional microbiological tests (CMTs) in AIDS patients with suspected opportunistic infections.

Methods

From January 2018 to February 2021, a retrospective study was performed at four tertiary teaching hospitals in China and data of 86 AIDS patients with suspected opportunistic infections were collected. The pathogen detection performance of mNGS and CMTs were compared.

Results

Positive agreement between mNGS and clinical diagnosis was significantly higher than that of CMTs (65/86 (75.6%) vs 37/86 (43.0%)). In addition, mNGS identified more bacterial (25 vs 2), fungal (5 vs 3), viral (9 vs 2) organisms compared with CMTs. Mixed infection were detected in 34 patients by mNGS combined with CMTs. Viruses (94.1%, 32/34) and fungi (94.1%, 32/34) were commonly seen in the mixed infection cases. mNGS helped identify the pathogen or guide appropriate treatment in 49/86 (57%) patients. Meanwhile, CMTs also contributed in the decision of appropriate treatment in 28 patients. The successful de-escalation or discontinuation of treatment was supported in 37 patients with the help of mNGS. We observed a significant reduction in the number of patients being prescribed foscarnet (52.3% vs 23.26%, p < 0.001), moxifloxacin (34.9% vs 10.5%, p = 0.005), and levofloxacin (32.6% vs 14%, p = 0.001) before and after mNGS.

Conclusion

For AIDS patients with suspected opportunistic infections, mNGS can provide early, noninvasive, and rapid microbiological diagnosis. mNGS may lead to a more precise antimicrobial treatment and reduced the unreasonable use of antimicrobials.

Addressing TB-related mortality in adults living with HIV: a review of the challenges and potential solutions

Tuberculosis (TB) is the leading cause of death in people living with HIV (PLHIV) globally, causing 208,000 deaths in PLHIV in 2019. PLHIV have an 18-fold higher risk of TB, and HIV/TB mortality is highest in inpatient facilities, compared with primary care and community settings. Here we discuss challenges and potential mitigating solutions to address TB-related mortality in adults with HIV. Key factors that affect healthcare engagement are stigma, knowledge, and socioeconomic constraints, which are compounded in people with HIV/TB co-infection. Innovative approaches to improve healthcare engagement include optimizing HIV/TB care integration and interventions to reduce stigma. While early diagnosis of both HIV and TB can reduce mortality, barriers to early diagnosis of TB in PLHIV include difficulty producing sputum specimens, lower sensitivity of TB diagnostic tests in PLHIV, and higher rates of extra pulmonary TB. There is an urgent need to develop higher sensitivity biomarker-based tests that can be used for point-of-care diagnosis. Nonetheless, the implementation and scale-up of existing tests including molecular World Health Organization (WHO)-recommended diagnostic tests and urine lipoarabinomannan (LAM) should be optimized along with expanded TB screening with tools such as C-reactive protein and digital chest radiography. Decreased survival of PLHIV with TB disease is more likely with late HIV diagnosis and delayed start of antiretroviral (ART) treatment. The WHO now recommends starting ART within 2 weeks of initiating TB treatment in the majority of PLHIV, aside from those with TB meningitis. Dedicated TB treatment trials focused on PLHIV are needed, including interventions to improve TB meningitis outcomes given its high mortality, such as the use of intensified regimens using high-dose rifampin, new and repurposed drugs such as linezolid, and immunomodulatory therapy. Ultimately holistic, high-quality, person-centered care is needed for PLHIV with TB throughout the cascade of care, which should address biomedical, socioeconomic, and psychological barriers.

Exploring the value of Mycobacterium tuberculosis modified lipoprotein as a potential biomarker for TB detection in children

Background

Current TB diagnostic methods available have been developed for adults and development efforts have neglected the differences in disease and sampling that occur between adults and children. Diagnostic challenges are even greater in HIV co-infected children and infants.

Methods and results

We established a sandwich ELISA assay to detect Mycobacterium tuberculosis modified lipoprotein (TLP) ex vivo in plasma. The study population contains plasma samples from 21 patients with active TB and 24 control samples with no TB, collected in the International Maternal Pediatric Adolescent AIDS Clinical Trails (IMPAACT) P1041 study. Retrospective analysis was performed and the results demonstrate that the median plasma levels of TLP in control subjects are 2.7 fold higher than the median plasma values in active TB subjects (p < 0.001).

Conclusions

Plasma levels of TLP are elevated with active TB disease in HIV positive subjects and deserves further exploration as an indicator for TB detection in children.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07140-9.

High-sensitivity C-reactive protein in HIV care: Tuberculosis diagnosis and short-term mortality in a cohort of Kenyan HIV patients in the DREAM programme

OBJECTIVE

Tuberculosis (TB) is the leading cause of death in HIV-positive people. In Kenya, 140 000 new TB cases occurred in 2019, and 13 000 HIV-positive patients died due to TB. The objective of this study was to investigate the role of high-sensitivity C-reactive protein (HS-CRP) in TB diagnosis and the prediction of mortality in HIV-positive patients.

METHODS

The IDEA-TB Study enrolled HIV-positive adult patients attending three DREAM centres in Kenya who were suspected of having TB. A lateral flow urine lipoarabinomannan assay (LF-LAM), serum HS-CRP, and GeneXpert MTB/RIF assay (Xpert MTB/RIF) were performed. Six-month survival was evaluated.

RESULTS

A total of 574 patients were enrolled. The median (interquartile range) age, body mass index, and CD4 count were 45 years (37-54 years), 20.5 kg/m² (18.5-23.69 kg/m²), and 477 cells/mL (290-700 cells/mL), respectively. TB was confirmed in 87 (15.2%) patients. Concordance between the Xpert MTB/RIF and LF-LAM tests was 87.1%. HS-CRP was higher in TB patients (35.39 mg/l vs 9.21 mg/l). Malnutrition and elevated HS-CRP were associated with TB: odds ratio (OR) 2.5 (95% confidence interval (CI) 1.14-5.72) and OR 6.6 (95% CI 3.87-11.52), respectively. Nine (1.6%) patients died during follow-up. No single factor was associated with mortality. Only the combination of malnutrition and elevated HS-CRP was highly predictive of death (odds ratio (OR) 9.8, 95% CI 1.88-50.95); the association was stronger in TB patients (33.3% vs 1.0%; OR 47.6, 95% CI 7.03-322.23).

CONCLUSION

TB diagnosis in HIV-positive patients remains challenging. HS-CRP could play a role in predicting early mortality in symptomatic patients.

Impact of the implementation of new guidelines on the management of patients with HIV infection at an advanced HIV clinic in Kinshasa, Democratic Republic of Congo (DRC)

BACKGROUND

HIV continues to be the main determinant morbidity with high mortality rates in Sub-Saharan Africa, with a high number of patients being late presenters with advanced HIV. Clinical management of advanced HIV patients is thus complex and requires strict adherence to updated, empirical and simplified guidelines. The current study investigated the impact of the implementation of a new clinical guideline on the management of advanced HIV in Kinshasa, Democratic Republic of Congo (DRC).

METHODS

A retrospective analysis of routine clinical data of advanced HIV patients was conducted for the periods; February 2016 to March 2017, before implementation of new guidelines, and November 2017 to July 2018, after the implementation of new guidelines. Eligible patients were patients with CD4 < 200 cell/μl and presenting with at least 1 of 4 opportunistic infections. Patient files were reviewed by a medical doctor and a committee of 3 other doctors for congruence. Statistical significance was set at 0.05%.

RESULTS

Two hundred four and Two hundred thirty-one patients were eligible for inclusion before and after the implementation of new guidelines respectively. Sex and age distributions were similar for both periods, and median CD4 were 36 & 52 cell/μl, before and after the new guidelines implementation, respectively. 40.7% of patients had at least 1 missed/incorrect diagnosis before the new guidelines compared to 30% after new guidelines, p < 0.05. Clinical diagnosis for TB and toxoplasmosis were also much improved after the implementation of new guidelines. In addition, only 63% of patients had CD4 count test results before the new guidelines compared to 99% of patients after new guidelines. Death odds after the implementation of new guidelines were significantly lower than before new guidelines in a multivariate regression model that included patients CD4 count and 10 other covariates, p < 0.05.

CONCLUSIONS

Simplification and implementation of a new and improved HIV clinical guideline coupled with the installation of laboratory equipment and point of care tests potentially helped reduce incorrect diagnosis and improve clinical outcomes of patients with advanced HIV. Regulating authorities should consider developing simplified versions of guidelines followed by the provision of basic diagnostic equipment to health centers.

Management of TB/HIV co-infection: the state of the evidence

Tuberculosis (TB) and HIV are strongly linked. There is a 19 times increased risk of developing active TB in people living with HIV than in HIV-negative people with Sub-Saharan Africa being the hardest hit region. According to the WHO, 1.3 million people died from TB, and an additional 300,000 TB-related deaths among people living with HIV. Although some progress has been made in reducing TB-related deaths among people living with HIV due to the evolution of diagnostics, treatment and antiretroviral HIV treatment, multi drug resistant TB is becoming a source of worry. Though significant progress has been made at the national level, understanding the state of the evidence and the challenges will better inform the national response of the opportunities for improved patient outcomes.

FUNDING

None.

Tuberculosis Chemotherapy Outcome in the Littoral Region of Cameroon: A Meta-analysis of Treatment Success Rate between 2014 and 2016

Background

Tuberculosis (TB) is a public health concern, especially in resource-constrained countries like Cameroon. TB drug resistance is a major obstacle to control and prevent.

Design

Data from 2014 to 2016 on the outcome of anti-TB treatment in the Littoral Region were reviewed manually and analysed using the meta-analysis concept. The treatment success rates (TSR) were the primary outcome used for this study. The heterogeneity statistics (I ²) was computed to orientate the choice of the best statistical model (binary fixed effect or random) to compute pooled value of TSR.

Results

Using an intention-to-treat analysis, the pooled proportions of HIV-uninfected TB patients successfully cured from TB were low and slightly decreased by 1% between 2014 and 2016. Regarding HIV-infected TB patients, pooled values of TSR were lower than those of their HIV-negative counterparts with values ranging from 71% (95% CI: 63%-83%; I ² = 71.16%) in 2014 to 68% (95% CI: 58%-79%; I ² = 70.97%) in 2016. In addition, no heterogeneity was found in three years (I ² = 0.0%; P value = 1). These cure rates were strongly and negatively correlated with the rates of patients lost to follow-up regardless of the year. In HIV-infected patients, the pooled values of ITT analysis-based treatment success rates were 73% (χ ² = 13.92, P value = 0.0002), 71% (χ ² = 7.26, P value = 0.007), and 68% (χ ² = 8.02, P value = 0.004), respectively. The coverage rates with cotrimoxazole (CTX) gradually increased over year ranging from 78.90% in 2014 to 94.17% in 2016, similar to the coverage rate for ARV therapy that was 60.06% in 2014 against 90% in 2016. A positive and statistically significant correlation was found between the success of the anti-TB therapy in HIV-infected patients and coverage rates with CTX and ARV.

Conclusion

An improvement in the reduction of percentage of lost to follow-up and coverage with CTX and ARV therapy could greatly increase chances to efficiently control TB in Cameroon.

Tackling cryptococcal meningitis in Nigeria, one-step at a time; the impact of training

BACKGROUND

Nigeria is estimated to have 25,000 cases of cryptococcal antigenemia (CrAg) annually. CrAg screening with pre-emptive fluconazole treatment is recommended but not yet implemented in Nigeria. Trainings were conducted to improve health-care provider (HCP) awareness and clinical skills in the management and prevention of cryptococcal meningitis (CM).

METHODS

HCPs providing care for people living with HIV were targeted for training at 13 sites from April to November 2018 Course content was adapted from CDC Cryptococcal Screening Program Training Manual and LIFE-website. "Hands-on" training on CrAg testing and lumbar puncture was included. A 14-point pre and post-test assessment instrument was designed to capture the impact of the training and focus group discussions (FGDs) were conducted.

RESULTS

A total of 761 HCPs were trained. 519 HCPs completed the pre-test evaluation while 470 (90.6%) took part in the post-test evaluation. Post-training, HCPs were significantly more likely to respond correctly to all 14 assessment items, with the mean percentage score rising to 91.0% from a pre-training value of 60.0%. FGDs revealed that many of the HCPs were not aware of the CrAg screening and pre-emptive treatment recommendations in Nigerian guidelines, and reported not having seen or managed a case of CM. Also, they highlighted challenges with routine CrAg screening due to a lack of access to CD4 testing, CrAg test kits, antifungal drugs, as well as the need for similar trainings across all tiers of care in Nigeria.

CONCLUSION

Training significantly improved HCPs' understanding of Nigerian policy on CrAg screening, CM diagnosis and best management practices. This training could be included in routine capacity building efforts for HCPs involved in HIV care in Nigeria.

Performance of and Factors Associated With Tuberculosis Screening and Diagnosis Among People Living With HIV: Analysis of 2012-2016 Routine HIV Data in Tanzania

People Living with HIV (PLHIV) should be screened for tuberculosis (TB) at every visit to the HIV care and treatment clinic (CTC), and those with positive results on screening should undergo further diagnostic investigations. We evaluated the performance of the TB diagnosis cascade among PLHIV attending CTC between January 2012 and December 2016 in three regions of Tanzania: Dar es Salaam, Iringa, and Njombe. We used descriptive epidemiology to evaluate performance and logistic regression to determine odds ratios (OR) for factors associated with TB screening and further TB diagnosis after positive TB screening. We analyzed 169,741 PLHIV who made 2,638,876 visits to CTC between January 2012 and December 2016. We excluded 2,074 (0.80%) visits as these involved PLHIV enrolled in CTC with a prior TB disease diagnosis. Of the 2,636,802 visits, 2,524,494 (95.67%) had TB screening according to national guidelines, of which 88,028 (3.49%) had TB screening positive results. Of the 88,028 visits with a positive TB screening, 27,810 (31.59%) had no records for further TB diagnosis following positive TB screening. Of all visits with positive TB screening, 32,986 (37.50%) had a TB disease diagnosis. On multivariate logistic regression, those who visited with World Health Organization (WHO) clinical stage four (aOR = 3.61, 95% CI 3.48–3.75, P < 0.001), enrolled in health center (aOR = 1.26, 95% CI 1.24–1.29, P < 0.001), enrolled in Iringa region (aOR = 1.54, 95% CI 1.50–1.57, P < 0.001), and enrolled in 2015 (aOR = 1.20, 95% CI 1.18–1.24, P < 0.001) were more likely to have no TB screening. Visits involving those who were of the female sex (aOR = 1.14, 95% CI 1.11–1.18, P < 0.001), enrolled in Njombe region (aOR = 4.36, 95% CI 4.09–4.65, P < 0.001), and enrolled in 2016 (aOR = 2.62, 95% CI 2.49–2.77, P < 0.001) were more likely to have no further TB diagnosis after positive TB screening. The study documented high performance of TB screening for PLHIV in HIV CTCs but a low transition of presumptive TB case undergoing further investigations. Better systems are needed for ensuring presumptive TB cases are diagnosed including using more efficient diagnostic methods like Gene pert.

HIV-infected patients with opportunistic pulmonary infections misdiagnosed as lung cancers: the clinicoradiologic features and initial application of CT radiomics

Background

To characterize clinicoradiologic and radiomic features for identifying opportunistic pulmonary infections (OPIs) misdiagnosed as lung cancers in patients with human immunodeficiency virus (HIV).

Methods

Twenty-four HIV-infected patients who were misdiagnosed with lung cancers on CT images and had OPIs confirmed by pathological examination or integration of clinical and laboratory findings and 49 HIV-infected patients with lung cancers confirmed pathologically were included. Semiautomated segmentation of the lesion was implemented with an in-house software. The lesion boundary was adjusted manually by radiologists. A total of 99 nonenhanced-CT-based radiomic features were then extracted with PyRadiomics. The clinicoradiologic and radiomic features were compared between the OPI and cancer groups.

Results

In the OPI group, 19 patients (79.2%) had tuberculosis (TB) infections, 2 (8.3%) had nontuberculosis mycobacterium (NTM) infections, 2 (8.3%) had cryptococcus infections and 1 (4.2%) had a mixed infection of TB and NTM. There were significant differences in age, proportion of smokers, smoking index, highly active antiretroviral therapy (HAART) duration, CD4⁺ counts and CD4⁺/CD8⁺ ratio between the two groups (P=0.000, 0.012, 0.007, 0.002, 0.000, and 0.000, respectively). In peripheral-type lesions, the presence of pleural indentation was less common, and the presence of satellite lesions was more common in the OPI group (P=0.016 and 0.020, respectively). Four radiomic parameters of central-type lesions were significantly different, including large dependence high gray level emphasis (LDHGLE), skewness, inverse difference normalized (IDN) and kurtosis (P=0.008, 0.017, 0.017, and 0.017, respectively). However, neither CT features of central-type lesions nor radiomic parameters of peripheral-type lesions were significantly different between the two groups.

Conclusions

Clinicoradiologic features together with radiomics may help identify OPIs mimicking lung cancers in HIV-infected patients.

Tuberculosis decline in populations affected by HIV: a retrospective study of 12 countries in the WHO African Region

Objective

To investigate which of the World Health Organization recommended methods for tuberculosis control have had the greatest effect on case incidence in 12 countries in the World Health Organization (WHO) African Region that carry high burdens of tuberculosis linked to human immunodeficiency virus (HIV) infection.

Methods

We obtained epidemiological surveillance, survey and treatment data on HIV and tuberculosis for the years 2003 to 2016. We used statistical models to examine the effects of antiretroviral therapy (ART) and isoniazid preventive therapy in reducing the incidence of tuberculosis among people living with HIV. We also investigated the role of tuberculosis case detection and treatment in preventing Mycobacterium tuberculosis transmission and consequently reducing tuberculosis incidence.

Findings

Between 2003 and 2016, ART provision was associated with the decline of tuberculosis in each country, and with differences in tuberculosis decline between countries. Inferring that ART was a cause of tuberculosis decline, ART prevented 1.88 million (95% confidence interval, CI: 1.65 to 2.11) tuberculosis cases in people living with HIV, or 15.7% (95% CI: 13.8 to 17.6) of the 11.96 million HIV-positive tuberculosis cases expected. Population coverage of isoniazid preventive therapy was too low (average 1.0% of persons eligible) to have a major effect on tuberculosis decline, and improvements in tuberculosis detection and treatment were either weakly associated or not significantly associated with tuberculosis decline.

Conclusion

ART provision is associated with tuberculosis decline in these 12 countries. ART should remain central to tuberculosis control where rates of tuberculosis–HIV coinfection are high, but renewed efforts to treat tuberculosis are needed.

Utility of Whole-Genome Next-Generation Sequencing of Plasma in Identifying Opportunistic Infections in HIV/AIDS

Background:

AIDS-associated Opportunistic Infections (OIs) have significant morbidity and mortality and can be diagnostically challenging, requiring invasive procedures as well as a combination of culture and targeted molecular approaches.

Objective:

We aimed to demonstrate the clinical utility of Next-generation Sequencing (NGS) in pathogen identification; NGS is a maturing technology enabling the detection of miniscule amounts of cell-free microbial DNA from the bloodstream.

Methods:

We utilized a novel Next-generation Sequencing (NGS) test on plasma samples to diagnose a series of HIV-associated OIs that were diagnostically confirmed through conventional microbial testing.

Results:

In all cases, NGS test results were available sooner than conventional testing. This is the first case series demonstrating the utility of whole-genome NGS testing to identify OIs from plasma in HIV/AIDS patients.

Conclusion:

NGS approaches present a clinically-actionable, comprehensive means of diagnosing OIs and other systemic infections while avoiding the labor, expense, and delays of multiple tests and invasive procedures.

Tuberculosis Case Finding With Combined Rapid Point-of-Care Assays (Xpert MTB/RIF and Determine TB LAM) in HIV-Positive Individuals Starting Antiretroviral Therapy in Mozambique

Background

Tuberculosis is a major health concern in several countries, and effective diagnostic algorithms for use in human immunodeficiency virus (HIV)-positive patients are urgently needed.

Methods

At prescription of antiretroviral therapy, all patients in 3 Mozambican health centers were screened for tuberculosis, with a combined approach: World Health Organization (WHO) 4-symptom screening (fever, cough, night sweats, and weight loss), a rapid test detecting mycobacterial lipoarabinomannan in urine (Determine TB LAM), and a molecular assay performed on a sputum sample (Xpert MTB/RIF; repeated if first result was negative). Patients with positive LAM or Xpert MTB/RIF results were referred for tuberculosis treatment.

Results

Among 972 patients with a complete diagnostic algorithm (58.5% female; median CD4 cell count, 278/μL; WHO HIV stage I, 66.8%), 98 (10.1%) tested positive with Xpert (90, 9.3%) or LAM (34, 3.5%) assays. Compared with a single-test Xpert strategy, dual Xpert tests improved case finding by 21.6%, LAM testing alone improved it by 13.5%, and dual Xpert tests plus LAM testing improved it by 32.4%. Rifampicin resistance in Xpert-positive patients was infrequent (2.5%). Among patients with positive results, 22 of 98 (22.4%) had no symptoms at WHO 4-symptom screening. Patients with tuberculosis diagnosed had significantly lower CD4 cell counts and hemoglobin levels, more advanced WHO stage, and higher HIV RNA levels. Fifteen (15.3%) did not start tuberculosis treatment, mostly owing to rapidly deteriorating clinical conditions or logistical constraints. The median interval between start of the diagnostic algorithm and start of tuberculosis treatment was 7 days.

Conclusions

The prevalence of tuberculosis among Mozambican HIV-positive patients starting antiretroviral therapy was 10%, with limited rifampicin resistance. Use of combined point-of-care tests increased case finding, with a short time to treatment. Interventions are needed to remove logistical barriers and prevent presentation in very advanced HIV/tuberculosis disease.

Opportunistic and non-opportunistic intestinal parasites in HIV/ AIDS patients in relation to their clinical and epidemiological status in a specialized medical service in Goiás, Brazil

Patients infected with the Human Immunodeficiency Virus (HIV) often have opportunistic infections, among which strongyloidiasis and coccidiosis are the most common parasitic infections that aggravate their health status. This study examined the prevalence of intestinal parasites, particularly of Strongyloides stercoralis and intestinal coccidia in patients with the Human Immunodeficiency Virus (HIV)/ Acquired Immunodeficiency Syndrome (AIDS) who were treated at the Specialized Assistance Service (SAE) of Jataí, State of Goiás, Brazil, and analyzed its correlation with clinical, laboratory, and socio-epidemiological parameters. A total of 270 stool samples were analyzed by the Lutz technique, Rugai's method, Agar Plate Culture, Ritchie's method and specific staining, Ziehl-Neelsen modified technique, Kinyoun's method and the rapid safranin method. The prevalence of intestinal parasites was 28.88% including 3.8% of S. stercoralis, Cryptosporidium sp. and Cystoisospora belli. There was a significant positive correlation between intestinal parasites and the clinical status and the use of antiretroviral therapy (ART), smoking, CD4+ lymphocyte counts and sexual orientation. In conclusion, the widespread use of antiretroviral therapy and health assistance contributed to the low prevalence of S. stercoralis and coccidiosis in patients with HIV/ AIDS who were followed up at the SAE.

L. M. C. F, Ottenhoff THM. IgA and IgG against Mycobacterium tuberculosis Rv2031 discriminate between pulmonary tuberculosis patients, Mycobacterium tuberculosis-infected and non-infected individuals

As part of a major project to investigate protective and diagnostic immune markers against tuberculosis (TB), we measured antibody isotype responses to Mycobacterium tuberculosis (Mtb) antigens (LAM, Rv2031, and HBHA) in cohorts of 149 pulmonary tuberculosis patients (PTBP), 148 household contacts (HHCs), and 68 community controls (CCs) in an endemic setting. ELISA was used to measure levels of IgA, IgG, and IgM from sera of cohorts at baseline, and at 6 and 12 months from entry. The results show that there were significant differences in IgA, IgG, and IgM responses to the different antigens and in the three cohorts. At baseline, the level of IgM against RV2031 and LAM did not vary between cohorts, but the levels of IgA and IgG against Rv2031 were significantly higher in PTB patients than HHCs and CCs, followed by HHCs, and the lowest in CCs. In patients, there was a significant variation in antibody responses before and after chemotherapy. The levels of IgA and IgG against HBHA, and IgA against Rv2031 decreased significantly and remained low, while IgA and IgG against LAM increased significantly and remained high following chemotherapy. However, the levels of IgM against Rv2031 and LAM increased at 6 months but decreased again at 12 months. IgM against HBHA did not show any significant variation before and after chemotherapy. Similarly, there were also significant variations in antibody responses in HHCs over time. Our results show that there are significant variations in IgA, IgG and IgM responses to the different antigens and in the three cohorts, implying that not all antibody isotype responses are markers of clinical TB. In addition, the current and previous studies consistently show that IgA and IgG against Rv2031 discriminate between clinical disease, Mtb-infected and non-infected individuals.

The crucial roles of Th17-related cytokines/signal pathways in M. tuberculosis infection

Interleukin-17 (IL-17), IL-21, IL-22 and IL-23 can be grouped as T helper 17 (Th17)-related cytokines because they are either produced by Th17/Th22 cells or involved in their development. Here, we review Th17-related cytokines/Th17-like cells, networks/signals and their roles in immune responses or immunity against Mycobacterium tuberculosis (Mtb) infection. Published studies suggest that Th17-related cytokine pathways may be manipulated by Mtb microorganisms for their survival benefits in primary tuberculosis (TB). In addition, there is evidence that immune responses of the signal transducer and activator of transcription 3 (STAT3) signal pathway and Th17-like T-cell subsets are dysregulated or destroyed in patients with TB. Furthermore, Mtb infection can impact upstream cytokines in the STAT3 pathway of Th17-like responses. Based on these findings, we discuss the need for future studies and the rationale for targeting Th17-related cytokines/signals as a potential adjunctive treatment.

Discovery and Validation of a Six-Marker Serum Protein Signature for the Diagnosis of Active Pulmonary Tuberculosis

New non-sputum biomarker tests for active tuberculosis (TB) diagnostics are of the highest priority for global TB control. We performed in-depth proteomic analysis using the 4,000-plex SOMAscan assay on 1,470 serum samples from seven countries where TB is endemic. All samples were from patients with symptoms and signs suggestive of active pulmonary TB that were systematically confirmed or ruled out for TB by culture and clinical follow-up. HIV coinfection was present in 34% of samples, and 25% were sputum smear negative. Serum protein biomarkers were identified by stability selection using L1-regularized logistic regression and by Kolmogorov-Smirnov (KS) statistics. A naive Bayes classifier using six host response markers (HR6 model), including SYWC, kallistatin, complement C9, gelsolin, testican-2, and aldolase C, performed well in a training set (area under the sensitivity-specificity curve [AUC] of 0.94) and in a blinded verification set (AUC of 0.92) to distinguish TB and non-TB samples. Differential expression was also highly significant (P < 10⁻²⁰) for previously described TB markers, such as IP-10, LBP, FCG3B, and TSP4, and for many novel proteins not previously associated with TB. Proteins with the largest median fold changes were SAA (serum amyloid protein A), NPS-PLA2 (secreted phospholipase A2), and CA6 (carbonic anhydrase 6). Target product profiles (TPPs) for a non-sputum biomarker test to diagnose active TB for treatment initiation (TPP#1) and for a community-based triage or referral test (TPP#2) have been published by the WHO. With 90% sensitivity and 80% specificity, the HR6 model fell short of TPP#1 but reached TPP#2 performance criteria. In conclusion, we identified and validated a six-marker signature for active TB that warrants diagnostic development on a patient-near platform.

The clinical utility of the urine-based lateral flow lipoarabinomannan assay in HIV-infected adults in Myanmar: an observational study

BACKGROUND

The use of the point-of-care lateral flow lipoarabinomannan (LF-LAM) test may expedite tuberculosis (TB) diagnosis in HIV-positive patients. However, the test's clinical utility is poorly defined outside sub-Saharan Africa.

METHODS

The study enrolled consecutive HIV-positive adults at a tertiary referral hospital in Yangon, Myanmar. On enrolment, patients had a LF-LAM test performed according to the manufacturer's instructions. Clinicians managing the patients were unaware of the LF-LAM result, which was correlated with the patient's clinical course over the ensuing 6 months.

RESULTS

The study enrolled 54 inpatients and 463 outpatients between July 1 and December 31, 2015. On enrolment, the patients' median (interquartile range) CD4 T-cell count was 270 (128-443) cells/mm³. The baseline LF-LAM test was positive in 201/517 (39%). TB was confirmed microbiologically during follow-up in 54/517 (10%), with rifampicin resistance present in 8/54 (15%). In the study's resource-limited setting, extrapulmonary testing for TB was not possible, but after 6 months, 97/201 (48%) with a positive LF-LAM test on enrolment had neither died, required hospitalisation, received a TB diagnosis or received empirical anti-TB therapy, suggesting a high rate of false-positive results. Of the 97 false-positive tests, 89 (92%) were grade 1 positive, suggesting poor test specificity using this cut-off. Only 21/517 (4%) patients were inpatients with TB symptoms and a CD4 T-cell count of < 100 cells/mm³. Five (24%) of these 21 died, three of whom had a positive LF-LAM test on enrolment. However, all three received anti-TB therapy before death - two after diagnosis with Xpert MTB/RIF testing, while the other received empirical treatment. It is unlikely that knowledge of the baseline LF-LAM result would have averted any of the study's other 11 deaths; eight had a negative test, and of the three patients with a positive test, two received anti-TB therapy before death, while one died from laboratory-confirmed cryptococcal meningitis. The test was no better than a simple, clinical history excluding TB during follow-up (negative predictive value (95% confidence interval): 94% (91-97) vs. 94% (91-96)).

CONCLUSIONS

The LF-LAM test had limited clinical utility in the management of HIV-positive patients in this Asian referral hospital setting.

Performance of the Abbott RealTime MTB and MTB RIF/INH Assays in a Setting of High Tuberculosis and HIV Coinfection in South Africa

South Africa is a country with a high incidence of tuberculosis (TB), complicated by coinfection with human immunodeficiency virus (HIV). The Xpert MTB/RIF (Cepheid, Sunnyvale, CA, USA) is used in South Africa as the test for the initial diagnosis of TB, and other molecular platforms such as the m2000 (Abbott Molecular, Des Plaines, IL, USA) are widely used for molecular monitoring of HIV load. The latter platform is now also equipped with the RealTime (RT) MTB and RealTime MTB RIF/INH assays for TB and first-line drug resistance screening but has not been evaluated in settings of HIV and TB coinfection. A prospective clinical validation study was conducted at a community health center in Johannesburg, South Africa, and consenting individuals with presumptive pulmonary TB were enrolled. The performance of the Abbott assays was compared with those of the Xpert MTB/RIF, liquid culture, drug susceptibility testing, and clinical case definitions. A statistical analysis was performed on 206 individuals (73% were HIV positive). The sensitivity and specificity of the RT MTB were 82.5% (confidence interval [CI], 67.2 to 92.7) and 93.1% (CI, 86.2 to 97.2) on raw sputum and 77.5% (CI, 61.5 to 89.2) and 95.1% (CI, 88.9 to 98.4) on concentrated sputum, respectively, compared with those from liquid culture. The RT MTB correctly identified 17/35 more smear-negative culture-positive specimens than the Xpert MTB/RIF. Both the RT MTB and the Xpert MTB/RIF displayed sensitivities >70% and specificities >90% in HIV-positive individuals. The available drug resistance results concurred with MTBDRplus and drug susceptibility profiles. The RT MTB assay has similar diagnostic performance to the Xpert MTB/RIF and is suited to testing presumptive TB patients coinfected with HIV. The existing laboratory information system connectivity, training, and technical support make this a viable polyvalent option to scale up TB alongside HIV laboratory testing services in South Africa.