The association between the ratio of monocytes:lymphocytes at age 3 months and risk of tuberculosis (TB) in the first two years of life

Predictors of Microbiologically Confirmed Intrathoracic Tuberculosis

OBJECTIVE

To identify risk factors for microbiologically confirmed intrathoracic tuberculosis in children.

METHODS

Children, 6 mo to 15 y of age, attending the out-patient department of a tertiary care centre in India, with probable intrathoracic tuberculosis were enrolled. Microbiological confirmation of tuberculosis was defined as positivity on smear (Ziehl-Neelsen staining) and/or Xpert MTB/RIF and/or MGIT-960 culture. Association of various factors with microbiological confirmation were assessed by univariate and multivariate analysis.

RESULTS

Microbiologic confirmation was documented in 39 (25%) of 153 patients enrolled. On univariate analysis, microbiological positivity was associated with female gender, higher mean (SD) age [136.6 (31.8) vs. 117.3 (41.4) mo], parenchymal lesion on chest radiograph, low body mass index for age, having symptoms of cough and weight loss, lower mean (SD) hemoglobin [10.4 (1.37) g/dl vs. 11(1.52) g/dl; p = 0.04], and higher mean (SD) monocyte: lymphocyte ratio [0.38 (0.30) vs. 0.24 (0.02); p = 0.37]. Higher proportion of microbiologically negative children were BCG vaccinated (95% vs. 79%; p = 0.002). On multivariate analysis, microbiological positivity showed significant association with low body mass index for age (p = 0.033) and higher monocyte: lymphocyte ratio (p = 0.037).

CONCLUSIONS

Low body mass index for age and higher monocyte: lymphocyte ratios were associated with microbiological confirmation in children with intrathoracic tuberculosis.

The Cross-Species Mycobacterial Growth Inhibition Assay (MGIA) Project, 2010-2014

The development of a functional biomarker assay in the tuberculosis (TB) field would be widely recognized as a major advance in efforts to develop and to test novel TB vaccine candidates efficiently. We present preliminary studies using mycobacterial growth inhibition assays (MGIAs) to detect Mycobacterium bovis BCG vaccine responses across species, and we extend this work to determine whether a standardized MGIA can be applied in characterizing new TB vaccines. The comparative MGIA studies reviewed here aimed to evaluate robustness, reproducibility, and ability to reflect in vivo responses. In doing so, they have laid the foundation for the development of a MGIA that can be standardized and potentially qualified. A major challenge ahead lies in better understanding the relationships between in vivo protection, in vitro growth inhibition, and the immune mechanisms involved. The final outcome would be a MGIA that could be used with confidence in TB vaccine trials. We summarize data arising from this project, present a strategy to meet the goals of developing a functional assay for TB vaccine testing, and describe some of the challenges encountered in performing and transferring such assays.

Human Immunology of Tuberculosis

Immunology is a central theme when it comes to tuberculosis (TB). The outcome of human infection with Mycobacterium tuberculosis is dependent on the ability of the immune response to clear or contain the infection. In cases where this fails, the bacterium replicates, disseminates within the host, and elicits a pathologic inflammatory response, and disease ensues. Clinical presentation of TB disease is remarkably heterogeneous, and the disease phenotype is largely dependent on host immune status. Onward transmission of M. tuberculosis to new susceptible hosts is thought to depend on an excessive inflammatory response causing a breakdown of the lung matrix and formation of lung cavities. But this varies in cases of underlying immunological dysfunction: for example, HIV-1 infection is associated with less cavitation, while diabetes mellitus comorbidity is associated with increased cavitation and risk of transmission. In compliance with the central theme of immunology in tuberculosis, we rely on detection of an adaptive immune response, in the form of interferon-gamma release assays or tuberculin skin tests, to diagnose infection with M. tuberculosis. Here we review the immunology of TB in the human host, focusing on cellular and humoral adaptive immunity as well as key features of innate immune responses and the underlying immunological dysfunction which associates with human TB risk factors. Our review is restricted to human immunology, and we highlight distinctions from the immunological dogma originating from animal models of TB, which pervade the field.

The SIGLEC14 null allele is associated with Mycobacterium tuberculosis- and BCG-induced clinical and immunologic outcomes

Humans exposed to Mycobacterium tuberculosis (Mtb) have variable susceptibility to tuberculosis (TB) and its outcomes. Siglec-5 and Siglec-14 are members of the sialic-acid binding lectin family that regulate immune responses to pathogens through inhibitory (Siglec-5) and activating (Siglec-14) domains. The SIGLEC14 coding sequence is deleted in a high proportion of individuals, placing a SIGLEC5-like gene under the expression of the SIGLEC14 promoter (the SIGLEC14 null allele) and causing expression of a Siglec-5 like protein in monocytes and macrophages. We hypothesized that the SIGLEC14 null allele was associated with Mtb replication in monocytes, T-cell responses to the BCG vaccine, and clinical susceptibility to TB. The SIGLEC14 null allele was associated with protection from TB meningitis in Vietnamese adults but not with pediatric TB in South Africa. The null allele was associated with increased IL-2 and IL-17 production following ex-vivo BCG stimulation of blood from 10 week-old South African infants vaccinated with BCG at birth. Mtb replication was increased in THP-1 cells overexpressing either Siglec-5 or Siglec-14 relative to controls. To our knowledge, this is the first study to demonstrate an association between SIGLEC expression and clinical TB, Mtb replication, or BCG-specific T-cell cytokines.

Monocyte/lymphocyte ratio predicts the severity of coronary artery disease: a syntax score assessment

Background

We aimed to explore whether monocyte to lymphocyte ratio (MLR) provides predictive value of the lesion severity in patients with coronary artery disease (CAD).

Methods

Five hundred forty-three patients undergoing coronary angiography were analyzed in this retrospective study. Patients with coronary stenosis were divided into three groups on the basis of Syntax score. The control group consisted of patients with normal coronary arteries. MLR was calculated by dividing monocytes count by lymphocytes count obtained from routine blood examination. Multivariate logistic analysis was used to assess risk factors of CAD. Ordinal logistic regression analysis was used to assess the relationship between MLR and the lesion severity of coronary arteries.

Results

MLR was found to be an independent risk factor of the presence of CAD (OR: 3.94, 95% CI: 1.20–12.95) and a predictor of the lesion severity (OR: 2.05, 95% CI: 1.15–3.66). Besides, MLR was positively correlated with Syntax score(r = 0.437, p < 0.001). In the receiver-operating characteristic (ROC) curve analysis, MLR, with an optimal cut-off value of 0.25, predicted the severe coronary lesion with a sensitivity of 60.26% and specificity of 78.49%.

Conclusions

MLR was an independent risk factor of the presence of CAD, and a predictor of the lesion severity. Compared to neutrophil to lymphocyte ratio (NLR), MLR has better performance to reflect the severity of coronary lesion.

Variable BCG efficacy in rhesus populations: Pulmonary BCG provides protection where standard intra-dermal vaccination fails

M.bovis BCG vaccination against tuberculosis (TB) notoriously displays variable protective efficacy in different human populations. In non-human primate studies using rhesus macaques, despite efforts to standardise the model, we have also observed variable efficacy of BCG upon subsequent experimental M. tuberculosis challenge. In the present head-to-head study, we establish that the protective efficacy of standard parenteral BCG immunisation varies among different rhesus cohorts. This provides different dynamic ranges for evaluation of investigational vaccines, opportunities for identifying possible correlates of protective immunity and for determining why parenteral BCG immunisation sometimes fails. We also show that pulmonary mucosal BCG vaccination confers reduced local pathology and improves haematological and immunological parameters post-infection in animals that are not responsive to induction of protection by standard intra-dermal BCG. These results have important implications for pulmonary TB vaccination strategies in the future.

Quantitative and qualitative profiles of circulating monocytes may help identifying tuberculosis infection and disease stages

Tuberculosis (TB) is one of the most important cause of morbidity and death among infectious diseases, and continuous efforts are needed to improve diagnostic tools and therapy. Previous published studies showed that the absolute cells number of monocytes or lymphocytes in peripheral blood or yet the ratio of monocytes to lymphocytes displayed the ability to predict the risk of active TB. In the present study we evaluated the ratio of monocytes to lymphocytes variation and we also analyzed the ex-vivo expression of CD64 on monocytes as tools to identify biomarkers for discriminating TB stages. Significant differences were found when the average ratio of monocytes to lymphocytes of active TB patients was compared with latent TB infection (LTBI) subjects, cured TB and healthy donors (HD). By the receiver operator characteristics (ROC) curve analysis the cut-off value of 0.285, allowed the discrimination of active TB from HD, with a sensitivity of 91.04% and a specificity of 93.55% (95% of confidence interval: 0.92-0.99). The ROC curve analysis comparing TB patients and LTBI groups, led to a sensitivity and the specificity of the assay of 85.07% and 85.71%, respectively (95% of confidence interval: 0.85 to 0.96). The upregulation of CD64 expression on circulating monocytes in active TB patients could represent an additional biomarker for diagnosis of active TB. In conclusion, we found that the ML ratio or monocyte absolute count or phenotypic measures show predictive value for active TB.

An Integrated Workflow To Assess Technical and Biological Variability of Cell Population Frequencies in Human Peripheral Blood by Flow Cytometry

In the context of large-scale human system immunology studies, controlling for technical and biological variability is crucial to ensure that experimental data support research conclusions. In this study, we report on a universal workflow to evaluate both technical and biological variation in multiparameter flow cytometry, applied to the development of a 10-color panel to identify all major cell populations and T cell subsets in cryopreserved PBMC. Replicate runs from a control donation and comparison of different gating strategies assessed the technical variability associated with each cell population and permitted the calculation of a quality control score. Applying our panel to a large collection of PBMC samples, we found that most cell populations showed low intraindividual variability over time. In contrast, certain subpopulations such as CD56 T cells and Temra CD4 T cells were associated with high interindividual variability. Age but not gender had a significant effect on the frequency of several populations, with a drastic decrease in naive T cells observed in older donors. Ethnicity also influenced a significant proportion of immune cell population frequencies, emphasizing the need to account for these covariates in immune profiling studies. We also exemplify the usefulness of our workflow by identifying a novel cell-subset signature of latent tuberculosis infection. Thus, our study provides a universal workflow to establish and evaluate any flow cytometry panel in systems immunology studies.

TB vaccine development and the End TB Strategy: importance and current status

TB is now the leading, global cause of death due to a single infectious microbe. To achieve the End TB vision of reducing TB by 90% by 2035 we will need new interventions. The objectives of this manuscript are to summarize the status of the clinical TB vaccine pipeline; to assess the challenges facing the TB development field; and to discuss some of the key strategies being embraced by the field to overcome these challenges. Currently, 8 of the 13 vaccines in clinical development are subunit vaccines; 6 of these contain or express either Ag85A or Ag85B proteins. A major challenge to TB vaccine development is the lack of diversity in both the antigens included in TB vaccines, and the immune responses elicited by TB vaccine candidates. Both will need to be expanded to maximise the potential for developing a successful candidate by 2025. Current research efforts are focused on broadening both antigen selection and the range of vaccine-mediated immune responses. Previous and ongoing TB vaccine efficacy trials have built capacity, generated high quality data on TB incidence and prevalence, and provided insight into immune correlates of risk of TB disease. These gains will enable the design of better TB vaccines and, importantly, move these vaccines into efficacy trials more rapidly and at a lower cost than was possible for previous TB vaccine candidates.

Lymphocyte-monocyte ratio at admission predicts possible outcomes in patients with acute-on-chronic liver failure

BACKGROUND

The lymphocyte-monocyte ratio (LMR) in the peripheral blood is suggested to be a potential biomarker for predicting the clinical outcomes of several diseases. We aimed to evaluate the relative efficiency of LMR for predicting 3-month mortality in patients with acute-on-chronic liver failure (AoCLF).

PATIENTS AND METHODS

In this study, 74 chronic hepatitis B patients, 90 AoCLF patients, and 70 healthy controls were followed up for 4 months. The primary endpoint was 3-month in-hospital mortality. Hematological and virological parameters as well as liver biochemistry were determined using blood samples ordered upon admission. A panel of clinical and biochemical variables were analyzed for potential associations with outcomes using Cox proportional hazards and multiple regression models.

RESULTS

A significantly lower LMR was detected in AoCLF patients than in healthy controls and chronic hepatitis B groups (both P=0.001). The LMR inversely correlated with model for end-stage liver disease scores, and a lower LMR was associated with increased 3-month mortality. Multivariate analysis suggested that both LMR and model for end-stage liver disease scores were independent predictors of 3-month mortality (P<0.01).

CONCLUSION

A low LMR measured at admission is predictive of a poor prognosis in AoCLF patients.

Correlates of tuberculosis risk: predictive biomarkers for progression to active tuberculosis

New approaches to control the spread of tuberculosis (TB) are needed, including tools to predict development of active TB from latent TB infection (LTBI). Recent studies have described potential correlates of risk, in order to inform the development of prognostic tests for TB disease progression. These efforts have included unbiased approaches employing “omics” technologies, as well as more directed, hypothesis-driven approaches assessing a small set or even individual selected markers as candidate correlates of TB risk. Unbiased high-throughput screening of blood RNAseq profiles identified signatures of active TB risk in individuals with LTBI, ≥1 year before diagnosis. A recent infant vaccination study identified enhanced expression of T-cell activation markers as a correlate of risk prior to developing TB; conversely, high levels of Ag85A antibodies and high frequencies of interferon (IFN)-γ specific T-cells were associated with reduced risk of disease. Others have described CD27⁻IFN-γ⁺CD4⁺ T-cells as possibly predictive markers of TB disease. T-cell responses to TB latency antigens, including heparin-binding haemagglutinin and DosR-regulon-encoded antigens have also been correlated with protection.

Further studies are needed to determine whether correlates of risk can be used to prevent active TB through targeted prophylactic treatment, or to allow targeted enrolment into efficacy trials of new TB vaccines and therapeutic drugs.

Promising biomarkers may allow accurate prediction of progression from infection to active TB diseasehttp://ow.ly/OzCL304ezfk

Distinct Transcriptional and Anti-Mycobacterial Profiles of Peripheral Blood Monocytes Dependent on the Ratio of Monocytes: Lymphocytes

The ratio of monocytes and lymphocytes (ML ratio) in peripheral blood is associated with tuberculosis and malaria disease risk and cancer and cardiovascular disease outcomes. We studied anti-mycobacterial function and the transcriptome of monocytes in relation to the ML ratio.

Mycobacterial growth inhibition assays of whole or sorted blood were performed and mycobacteria were enumerated by liquid culture. Transcriptomes of unstimulated CD14 + monocytes isolated by magnetic bead sorting were characterised by microarray. Transcript expression was tested for association with ML ratio calculated from leucocyte differential counts by linear regression.

The ML ratio was associated with mycobacterial growth in vitro (β = 2.23, SE 0.91, p = 0.02). Using sorted monocytes and lymphocytes, in vivo ML ratio (% variance explained R² = 11%, p = 0.02) dominated over in vitro ratios (R² = 5%, p = 0.10) in explaining mycobacterial growth. Expression of 906 genes was associated with the ML ratio and 53 with monocyte count alone. ML-ratio associated genes were enriched for type-I and -II interferon signalling (p = 1.2 × 10^− 8), and for genes under transcriptional control of IRF1, IRF2, RUNX1, RELA and ESRRB. The ML-ratio-associated gene set was enriched in TB disease (3.11-fold, 95% CI: 2.28–4.19, p = 5.7 × 10^− 12) and other inflammatory diseases including atopy, HIV, IBD and SLE.

The ML ratio is associated with distinct transcriptional and anti-mycobacterial profiles of monocytes that may explain the disease associations of the ML ratio.

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A pathophysiological basis for involvement of the ML ratio in infectious, malignant and cardiovascular diseases is unclear.

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Monocytes from individuals with high ML ratio have impaired control of mycobacterial growth and a distinctive transcriptome.

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These monocytes are characterised by enhanced interferon signalling, and intermediate transcription factors.

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The ML-ratio associated transcript signature is enriched in TB and other diseases including atopy, IBD and SLE.

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Ontogeny-specific function of monocytes may be the possible mechanism for the prognostic value of the ML ratio.

Enumeration of the absolute count of white blood cell subsets is one of the most frequently performed tests in clinical practice. Recently, elevation in the monocytes:lymphocytes (ML) ratio was linked to increased risk of tuberculosis and malaria disease, and poorer outcomes for many cancers and cardiovascular diseases. We sought to understand the mechanism of these disease associations. We found that the ML ratio reflects the functional capacity of monocytes and that genes that are differentially expressed in monocytes from donors with a high ML ratio are similar to those in other diseases such as HIV and inflammatory bowel disease. Because a specific type of blood-making stem cell regulates the ML ratio, it is plausible that the ratio reflects monocyte function because it is a clue to different monocyte origins. Our findings offer a mechanism for the predictive value of the ML ratio that may help improve its clinical utility.

Human newborn bacille Calmette-Guérin vaccination and risk of tuberculosis disease: a case-control study

BACKGROUND

An incomplete understanding of the immunological mechanisms underlying protection against tuberculosis (TB) hampers the development of new vaccines against TB. We aimed to define host correlates of prospective risk of TB disease following bacille Calmette-Guérin (BCG) vaccination.

METHODS

In this study, 5,726 infants vaccinated with BCG at birth were enrolled. Host responses in blood collected at 10 weeks of age were compared between infants who developed pulmonary TB disease during 2 years of follow-up (cases) and those who remained healthy (controls).

RESULTS

Comprehensive gene expression and cellular and soluble marker analysis failed to identify a correlate of risk. We showed that distinct host responses after BCG vaccination may be the reason: two major clusters of gene expression, with different myeloid and lymphoid activation and inflammatory patterns, were evident when all infants were examined together. Cases from each cluster demonstrated distinct patterns of gene expression, which were confirmed by cellular assays.

CONCLUSIONS

Distinct patterns of host responses to Mycobacterium bovis BCG suggest that novel TB vaccines may also elicit distinct patterns of host responses. This diversity should be considered in future TB vaccine development.

Dietary Vitamin D3 Suppresses Pulmonary Immunopathology Associated with Late-Stage Tuberculosis in C3HeB/FeJ Mice

Tuberculosis (TB) is a significant human disease caused by inhalation of Mycobacterium tuberculosis. Left untreated, TB mortality is associated with a failure to resolve pulmonary immunopathology. There is currently widespread interest in using vitamin D3 (VitD3) as an adjunct therapy for TB because numerous in vitro studies have shown that VitD3 has direct and indirect mycobactericidal activities. However, to date, there have been no in vivo studies addressing whether VitD3 affects experimental TB outcome. In this study, we used C3HeB/FeJ mice to determine whether dietary VitD3 influences the outcome of experimental TB. We observed that although M. tuberculosis burdens did not differ between mice on a VitD3-replete diet (VitD(HI) mice) and mice on a VitD3-deficient diet (VitD(LO) mice), the inflammatory response in VitD(HI) mice was significantly attenuated relative to VitD(LO) controls. Specifically, the expression of multiple inflammatory pathways was reduced in the lungs at later disease stages as were splenocyte IL12/23p40 and IFN-γ levels following ex vivo restimulation. Dietary VitD3 also suppressed the accumulation of T cells in the mediastinal lymph nodes and lung granulomatous regions while concomitantly accelerating the accumulation of F4/80(+) and Ly6C/Ly6G(+) lineages. The altered inflammatory profile of VitD(HI) mice also associated with reductions in pulmonary immunopathology. VitD receptor-deficient (vdr(-/-)) radiation bone marrow chimeras demonstrate that reductions in pulmonary TB immunopathology are dependent on hematopoietic VitD responsiveness. Collectively, our data support a model wherein the in vivo role of VitD3 during TB is not to promote M. tuberculosis killing but rather to function through hematopoietic cells to reduce M. tuberculosis-elicited immunopathology.

Discriminating Active Tuberculosis from Latent Tuberculosis Infection by flow cytometric measurement of CD161-expressing T cells

Interferon-gamma Release Assays (IGRAs) significantly increases the possibility for early diagnosis of tuberculosis, but IGRAs alone cannot discriminate active TB from LTBI. Therefore, fast and reliable discrimination of active tuberculosis, especially bacteriology negative tuberculosis, from LTBI is a great necessity. Here we established an assay based on flow cytometric multiparameter assay assessing expression of CD161 along with CD3, CD4, and CD8, whereby a set of indices formulated by the percentages of CD3⁺CD161⁺, CD3⁺CD4⁺CD161⁺ and CD3⁺CD8⁺CD161⁺ T cells multiplied with lymphocyte/monocyte ratio were established. Application of the CD3⁺CD8⁺CD161⁺ index to compare a cohort of active tuberculosis with a cohort of LTBI or health control yielded 0.7662 (95% confidence interval [CI] 0.6559–0.8552) or 0.7922 (95%  CI 0.6846–0.8763) for sensitivity and 0.9048 (95%  CI 0.8209–0.9580) or 0.8939 (95% CI 0.8392–0.9349) for specificity when the TB cohort was AFB⁺; the corresponding results were 0.7481 (95%  CI 0.6648–0.8198) or 0.7557 (95%  CI 0.6730–0.8265) for sensitivity and 0.8571 (95%  CI 0.7637–0.9239) or 0.8603 (95%  CI 0.8008–0.9075) for specificity when the TB cohort was AFB⁻. Our results reveal that in combination with IGRAs, CD161-based indices provide a novel, fast diagnostic solution addressing the limitation of current tuberculosis diagnostics.

Association between lymphocyte-to-monocyte ratio (LMR) and the mortality of HBV-related liver cirrhosis: a retrospective cohort study

OBJECTIVE

Infection with hepatitis B virus (HBV) remains a major cause of liver cirrhosis (LC) in China. Recent reports suggest that the lymphocyte-to-monocyte ratio (LMR) is a potential biomarker for predicting clinical outcomes. In our study, we investigated if LMR can be used as a prognostic marker of mortality in patients with HBV-related LC.

DESIGN

A retrospective cohort study.

SETTING

HBV-infected patients with LC and patients with chronic hepatitis B infection (CHB) from the Department of Infectious Disease were enrolled and 240 healthy individuals were recruited from the healthcare centre at the First Affiliated Hospital of Zhejiang University.

PARTICIPANTS

479 HBV-infected patients with LC, 134 patients with CHB and 240 healthy individuals were enrolled.

PRIMARY AND SECONDARY OUTCOME MEASURES

The receiver operating characteristic (ROC) curve and multivariable logistic regression analysis after adjusting for total protein, albumin, total bilirubin and the model for end-stage liver disease (MELD) score were used to evaluate the power of LMR for predicting 1 year mortality in patients with LC.

RESULTS

The LMR was statistically lower in patients with LC. The MELD score and mortality were statistically higher in patients with LC compared with the CHB and control groups. The area under the ROC curve, cut-off values, sensitivity and specificity of LMR for predicting mortality LC in the training cohort were 0.817 (95% CI 0.746 to 0.888; p<0.001), 2.10, 82.6 and 78.8%, and these data were confirmed in the validation cohort. The multivariate logistic regression analysis showed that LMR was an independent predictive factor of mortality in LC (OR 2.370, 95% CI (1.070 to 5.249); p=0.033).

CONCLUSIONS

Our results strongly suggest that low LMR can be considered as an independent biomarker for predicting mortality in patients with LC.

Biomarkers for risk of developing active tuberculosis in contacts of TB patients: a prospective cohort study

Identifying those Mycobacterium tuberculosis latent-infected individuals most at risk of developing active tuberculosis (TB) using routine clinical and laboratory tests remains a huge challenge in TB control efforts. We conducted a prospective longitudinal study of clinical and laboratory markers associated with the risk of developing active TB in contacts with latent M. tuberculosis infection.HIV-negative household contacts (n=296) of pulmonary TB patients underwent monitoring of clinical features, full blood cell counts, tuberculin skin text (TST) and chest radiography performed regularly during 18 months of follow-up. Paired statistical tests, a Kaplan-Meier analysis and Cox proportional hazard modelling were performed on variables between contacts progressing or not progressing to active TB.The appearance of TB disease symptoms in contacts was significantly associated with an elevated peripheral percentage of blood monocytes (adjusted hazard ratio (aHR) 6.25, 95% CI 1.63-23.95; p<0.01), a ≥14 mm TST response (aHR 5.72, 95% CI 1.22-26.80; p=0.03) and an increased monocyte:lymphocyte ratio (aHR 4.97, 95% CI 1.3-18.99; p=0.03). Among contacts having TST ≥14 mm, a strong association with risk of progression to TB was found with an elevated blood monocyte percentage (aHR 8.46, 95% CI 1.74-41.22; p<0.01).Elevated percentage of peripheral blood monocytes plus an elevated TST response are potential biomarkers for identifying contacts of TB patients at highest risk of developing active TB.

The translational value of non-human primates in preclinical research on infection and immunopathology

The immune system plays a central role in the defense against environmental threats - such as infection with viruses, parasites or bacteria - but can also be a cause of disease, such as in the case of allergic or autoimmune disorders. In the past decades the impressive development of biotechnology has provided scientists with biological tools for the development of highly selective treatments for the different types of disorders. However, despite some clear successes the translation of scientific discoveries into effective treatments has remained challenging. The often-disappointing predictive validity of the preclinical animal models that are used in the selection of the most promising vaccine or drug candidates is the Achilles heel in the therapy development process. This publication summarizes the relevance and usage of non-human primates as pre-clinical model in infectious and autoimmune diseases, in particular for biologicals, which due to their high species-specificity are inactive in lower species.

The association between the ratio of monocytes: lymphocytes and risk of tuberculosis among HIV-infected postpartum women

Recent human studies support historical animal studies that suggested an association between peripheral blood monocyte:lymphocyte (ML) ratio and tuberculosis (TB) disease. To evaluate generalizability of this finding, we modeled the association between peripartum ML ratio and incident TB disease within 18 months postpartum among 1202 HIV-infected women in South Africa, Tanzania, Uganda, and Zimbabwe. The ML ratio was associated with increased risk of TB disease independently to combination antiretroviral therapy, World Health Organization stage, or CD4 count (adjusted hazard ratio = 1.22, 95% confidence interval: 1.07 to 1.4, P = 0.003 per 0.1 unit increase in ML ratio).