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

IgG glycosylation associates with risk of progression from latent to active tuberculosis

OBJECTIVES

Glycosylation motifs shape antibody structure, stability and antigen affinity and play an important role in antibody localization and function. Serum IgG glycosylation profiles are significantly altered in infectious diseases, including tuberculosis (TB), but have not been studied in the context of progression from latent to active TB.

METHODS

We performed a longitudinal study of paired bulk IgG glycosylation and transcriptomic profiling in blood from individuals with active TB (ATB) or latent TB infection (LTBI) before and after treatment.

RESULTS

We identified that a combination of two IgG1 glycosylation traits were sufficient to distinguish ATB from LTBI with high specificity and sensitivity, prior to, and after treatment. Importantly, these two features positively correlated with previously defined cellular and RNA signatures of ATB risk in LTBI, namely monocyte to lymphocyte ratio and the expression of interferon (IFN)-associated gene signature of progression (IFN-risk signature) in blood prior to treatment. Additional glycosylation features at higher prevalence in LTBI individuals with high expression of the IFN-risk signature prior to treatment included fucosylation on IgG1, IgG2 and IgG3.

CONCLUSIONS

Together, our results demonstrate that bulk IgG glycosylation features could be useful in stratifying the risk of LTBI reactivation and progression to ATB.

Development and application of the direct mycobacterial growth inhibition assay: a systematic review

Introduction

First described by Wallis et al. in 2001 for the assessment of TB drugs, the direct mycobacterial growth inhibition assay (MGIA) offers a tractable ex vivo tool measuring the combined influences of host immunity, strain virulence and intervention effects. Over the past 13 years, we have led efforts to adapt the direct MGIA for the assessment of TB vaccines including optimisation, harmonisation and validation of BCG vaccine-induced responses as a benchmark, as well as assay transfer to institutes worldwide.

Methods

We have performed a systematic review on the primary published literature describing the development and applications of the direct MGIA from 2001 to June 2023 in accordance with the PRISMA reporting guidelines.

Results

We describe 63 studies in which the direct MGIA has been applied across species for the evaluation of TB drugs and novel TB vaccine candidates, the study of clinical cohorts including those with comorbidities, and to further understanding of potential immune correlates of protection from TB. We provide a comprehensive update on progress of the assay since its conception and critically evaluate current findings and evidence supporting its utility, highlighting priorities for future directions.

Discussion

While further standardisation and validation work is required, significant advancements have been made in the past two decades. The direct MGIA provides a potentially valuable tool for the early evaluation of TB drug and vaccine candidates, clinical cohorts, and immune mechanisms of mycobacterial control.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42023423491.

Monocyte to lymphocyte ratio and hemoglobin level to predict tuberculosis after antiretroviral therapy initiation

OBJECTIVE

To determine the performance of the baseline monocyte to lymphocyte ratio (MLR), baseline anemia severity and combination of these biomarkers, to predict tuberculosis (TB) incidence in people with HIV (PWH) after antiretroviral therapy (ART) initiation.

DESIGN

Multicenter, retrospective cohort study.

METHODS

We utilized the data from study A5175 (Prospective Evaluation of Antiretroviral Therapy in Resource-limited Settings: PEARLS). We assessed the utility of MLR, anemia severity and in combination, for predicting TB in the first year after ART. Cox regression was used to assess associations of MLR and anemia with incident TB. Harrell's C index was used to describe single model discrimination.

RESULTS

A total of 1455 participants with a median age of 34 [interquartile range (IQR) 29, 41] were included. Fifty-four participants were diagnosed with TB. The hazard ratio (HR) for incident TB was 1.77 [95% confidence interval (CI) 1.01-3.07]; P  = 0.04 for those with MLR ≥0.23. The HR for mild/mod anemia was 3.35 (95% CI 1.78-6.29; P  < 0.001) and 18.16 (95% CI 5.17-63.77; P  < 0.001) for severe anemia. After combining parameters, there were increases in adjusted HR (aHR) for MLR ≥0.23 to 1.83 (95% CI 1.05-3.18), and degrees of anemia to 3.38 (95% CI 1.80-6.35) for mild/mod anemia and 19.09 (95% CI 5.43-67.12) for severe anemia.

CONCLUSIONS

MLR and hemoglobin levels which are available in routine HIV care can be used at ART initiation for identifying patients at high risk of developing TB disease to guide diagnostic and management decisions.

Monocyte-to-lymphocyte, neutrophil-to-lymphocyte and neutrophil-to-monocyte plus lymphocyte ratios in children with active tuberculosis: A multicentre study

AIM

Higher number of monocytes and neutrophils may correlate with active tuberculosis (TB) in children. However, the few paediatric studies available are limited by the small numbers of children with TB disease or infection included.

METHODS

We calculated the monocyte-to-lymphocyte-ratio (MLR), neutrophil-to-lymphocyte-ratio (NLR) and neutrophil-to-monocyte-plus-lymphocyte-ratio (NMLR) in children with active TB, latent TB infection (LTBI), other infectious and non-infectious conditions and healthy children evaluated in two referral centres in Rome.

RESULTS

Overall, 649 children were included (41.8% females, mean age of 5.74 years). MLR, NLR and NMLR values were always significantly higher in patients with TB compared with the other groups (p < 0.001). Considering the entire population with the outcome of TB diagnosis, NMLR, with a cut-off of 1.2, had a sensitivity of 63% and a specificity of 76% (AUC: 0.71 [0.64-0.78]); NLR, with a cut-off of 1.5, had a sensitivity of 61% and a specificity of 79% (AUC: 0.72 [0.65-0.79]); MLR, considering a cut-off of 0.2, was less sensitive (56%) but more specific (82%) with a similar AUC (0.72 [0.65-0.79]).

CONCLUSION

Our study provides further evidence that MLR, NLR and NMLR can serve as first level diagnostics to support the clinical suspicion of TB in children.

Prognostic impact of monocyte-to-lymphocyte ratio in coronary heart disease: a systematic review and meta-analysis

OBJECTIVE

Inflammatory biomarkers are novel tools to assess the prognosis of different cardiovascular diseases. We evaluated the impact of the monocyte-to-lymphocyte ratio (MLR) on clinical outcomes in patients with coronary heart disease (CHD).

METHODS

We systematically screened English-language articles in PubMed, Scopus, and Web of Science to 31 August 2022. Relevant articles reporting the MLR and its association with clinical outcomes (major adverse cardiovascular events (MACE), coronary artery disease (CAD) severity, mortality, cardiac rupture, subclinical CAD, acute coronary syndrome (ACS) prediction, thin-cap fibroatheroma, no-reflow phenomenon, MLR-related differences in percutaneous coronary intervention, heart failure hospitalization, and depression) in patients with CHD were collected for further analysis.

RESULTS

Nineteen articles were selected. The mean MLR was 0.34. A higher MLR was significantly associated with an increased risk of MACE among patients with CHD. The MLR was an independent predictor of MACE in patients with ACS. No significant association was found for CAD severity. A complementary analysis was not performed because of few studies focusing on the other predefined endpoints.

CONCLUSIONS

The MLR is a simple and widely available tool to predict MACE in patients with CHD. This biomarker can be utilized in emergency settings to prioritize high-risk patients and optimize therapeutic interventions.

Prognostic value of monocyte-to-lymphocyte ratio for 90-day all-cause mortality in type 2 diabetes mellitus patients with chronic kidney disease

The role of inflammation and the correlation between inflammatory markers and type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD) have been studied. In clinical work, a large number of T2DM patients complicated with CKD, but the cause of CKD was not clear. Our study aimed to evaluate the relationship between monocyte-to-lymphocyte ratio (MLR) and mortality in T2DM patients with CKD. The data from Medical Information Mart for Intensive Care III was analyzed. The primary outcome was 90-day all-cause mortality; the secondary outcomes were the length of ICU stay, hospital mortality and 30-day all-cause mortality. Cox regression was used to evaluate the association between MLR and 90-day mortality. We performed subgroup analyses to determine the consistency of this association, and used Kaplan-Meier survival curve to analysis the survival of different levels of MLR. A total of 1830 patients were included in study retrospectively. The length of ICU stay, 30-day all-cause mortality, and 90-day all-cause mortality in the MLR > 0.71 group were significantly higher than those in the MLR < 0.28 and 0.28 ≤ MLR ≤ 0.71 group. In Cox regression analysis, high MLR level was significantly associated with increased greater risk of 90-day all-cause mortality. The adjusted HR (95%CIs) for the model 1, model 2, and model 3 were 2.429 (1.905-3.098), 2.070 (1.619-2.647), and 1.898 (1.478-2.437), respectively. Subgroup analyses also showed the consistency of association between MLR and 90-day all-cause mortality. The Kaplan-Meier survival curve analysis revealed that MLR > 0.71 had worst prognosis. In T2DM patients with CKD in the intensive care unit, high MLR was significantly associated with increased risk 90-day all-cause mortality.

The potential value of Notch1 and DLL1 in the diagnosis and prognosis of patients with active TB

Objectives

The Notch signaling pathway has been implicated in the pathogenesis of active tuberculosis (TB), and Th1-type cell-mediated immunity is essential for effective control of mycobacterial infection. However, it remains unclear whether Notch signaling molecules (Notch1, DLL1, and Hes1) and Th1-type factors (T-bet and IFN-γ) can serve as biomarkers for tracking the progression of active TB at different stages along with peripheral blood white blood cell (WBC) parameters.

Methods

A total of 60 participants were enrolled in the study, including 37 confirmed TB patients (mild (n=17), moderate/severe (n=20)) and 23 healthy controls. The mRNA expression of Notch1, DLL1, Hes1, T-bet and IFN-γ in the peripheral blood mononuclear cells (PBMCs) of the subjects was measured by RT-qPCR, then analyzed for differences. Receiver Operating Characteristic curve (ROC) was used to assess the effectiveness of each factor as a biomarker in identifying lung injury.

Results

We found that mRNA expression levels of Notch1, DLL1, and Hes1 were upregulated in active TB patients, with higher levels observed in those with moderate/severe TB than those with mild TB or without TB. In contrast, mRNA levels of T-bet and IFN-γ were downregulated and significantly lower in mild and moderate/severe cases. Furthermore, the combiROC analysis of IFN-γ and the percentage of lymphocytes (L%) among WBC parameters showed superior discriminatory ability compared to other factors for identifying individuals with active TB versus healthy individuals. Notably, Notch pathway molecules were more effective than Th1-type factors and WBC parameters in differentiating mild and moderate/severe cases of active TB, particularly in the combiROC model that included Notch1 and Hes1.

Conclusions

Our study demonstrated that Notch1, Hes1, IFN-γ, and L% can be used as biomarkers to identify different stages of active TB patients and to monitor the effectiveness of treatment.

Monocyte, Lymphocyte and Neutrophil Ratios - Easy-to-Use Biomarkers for the Diagnosis of Pediatric Tuberculosis

BACKGROUND

The neutrophil-to-lymphocyte-ratio (NLR), neutrophil-to-monocyte-plus-lymphocyte-ratio (NMLR) and monocyte-to-lymphocyte-ratio (MLR) may have diagnostic potential for tuberculosis (TB).

METHODS

Data of two prospective multicenter studies in Switzerland were used, which included children <18 years with TB exposure, infection or disease or with febrile non-TB lower-respiratory-tract infection (nTB-LRTI).

RESULTS

Of the 389 children included 25 (6.4%) had TB disease, 12 (3.1%) TB infection, 28 (7.2%) were healthy TB exposed and 324 (83.3%) nTB-LRTI. Median (IQR) NLR was highest with 2.0 (1.2, 2.2) in children with TB disease compared to TB exposed [0.8 (0.6, 1.3); P = 0.002] and nTB-LRTI [0.3 (0.1, 1.0); P < 0.001]. Median (IQR) NMLR was highest with 1.4 (1.2, 1.7) in children with TB disease compared to healthy exposed [0.7 (0.6, 1.1); P = 0.003] and children with nTB-LRTI [0.2 (0.1, 0.6); P < 0.001). Receiver operating characteristic curves to detect TB disease compared to nTB-LRTI for NLR and NMLR had an area under the curve of 0.82 and 0.86, the sensitivity of 88% and 88%, and specificity of 71% and 76%, respectively.

CONCLUSION

NLR and NMLR are promising, easy-to-obtain diagnostic biomarkers to differentiate children with TB disease from other lower respiratory tract infections. These results require validation in a larger study and in settings with high and low TB endemicity.

Advancing personalized medicine for tuberculosis through the application of immune profiling

While early and precise diagnosis is the key to eliminating tuberculosis (TB), conventional methods using culture conversion or sputum smear microscopy have failed to meet demand. This is especially true in high-epidemic developing countries and during pandemic-associated social restrictions. Suboptimal biomarkers have restricted the improvement of TB management and eradication strategies. Therefore, the research and development of new affordable and accessible methods are required. Following the emergence of many high-throughput quantification TB studies, immunomics has the advantages of directly targeting responsive immune molecules and significantly simplifying workloads. In particular, immune profiling has been demonstrated to be a versatile tool that potentially unlocks many options for application in TB management. Herein, we review the current approaches for TB control with regard to the potentials and limitations of immunomics. Multiple directions are also proposed to hopefully unleash immunomics' potential in TB research, not least in revealing representative immune biomarkers to correctly diagnose TB. The immune profiles of patients can be valuable covariates for model-informed precision dosing-based treatment monitoring, prediction of outcome, and the optimal dose prediction of anti-TB drugs.

Relationship between Glucose-6-Phosphate Dehydrogenase Deficiency, X-Chromosome Inactivation and Inflammatory Markers

Recent studies suggest that X-linked glucose-6-phosphate dehydrogenase (G6PD) deficiency entails a proinflammatory state that may increase the risk of several disease conditions. However, it is not clear how this relates to the degree of enzyme insufficiency and, in heterozygous females, to skewed inactivation of the X chromosome. This study aimed to (i) investigate the enzyme activity in a cohort of 232 subjects (54.3% females) from Northern Sardinia, Italy, further stratified into three subgroups (G6PD normal, partial deficiency and total deficiency); (ii) measure the levels of some non-specific inflammatory markers, such as erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and those derived from cell counts, such as neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR) and platelet-to-lymphocyte ratio (PLR), in relation to the underlying molecular defect and X inactivation. G6PD activity was measured in red blood cells according to G6PD/6PGD ratio, and X-chromosome inactivation was assessed by the HUMARA method. Overall, ESR was increased in males with total deficiency compared with normal males (15.0 ± 7.2 vs. 11.9 ± 6.2, p = 0.002, Tukey's test), albeit not in males with partial deficiency. High-sensitivity CRP was slightly increased in males with total deficiency, compared to males with normal G6PD activity (5.96 ± 3.39 vs. 3.95 ± 2.96, p = 0.048). In females, neither marker showed significant differences across the subgroups. MLR was significantly and progressively increased from normal to totally deficient subjects with intermediate values in partially deficient subjects (0.18, 0.31 and 0.37, ANOVA p = 0.008). The NLR and PLR were not different in the three subgroups. Our findings show that G6PD deficiency may be associated with a proinflammatory profile, especially in elderly females, and worsened by the concomitant asymmetric inactivation of the X chromosome.

Monocyte-to-lymphocyte ratio is significantly associated with positive QuantiFERON-TB Gold-In-Tube and adult survival: an observational study

This study aimed to find significant factors associated with tuberculosis (TB) infection and disease development. The participants were from National Health and Nutrition Examination Survey (NHANES) and National Death Index (NDI). The tuberculosis infection was defined as a positive QuantiFERON-TB Gold-In-Tube (QFT-GIT). The Least Absolute Shrinkage and Selection Operator (LASSO) model was used to screen variables associated with QFT-GIT among 23 laboratory measures. Then the logistic regression analyses were performed to assess the independent factors, followed by a comprehensive nomogram model construction. Receiver operating characteristic (ROC) and Decision Curve (DCA) analyses were used to assess the performance of comprehensive model on QFT-GIT result and death risk. Of 5256 individuals included, 521 individuals had positive QFT-GIT. LASSO analysis indicated that 11 variables were associated with QFT-GIT result, and logistic regression analyses further found sodium and monocyte-to-lymphocyte ratio (MLR) were independent factors. After adjusting for potential confounders, the correlation of sodium and MLR with QFT-GIT result was still observed. The comprehensive model based on sodium, MLR, and important clinical characteristics can predict 0.8 probability of positive QFT-GIT and achieve more clinical net benefit. ROC analysis by training and validation sets showed the favorable prediction performance. Comprehensive model also presented favorable performance in evaluating the death risk of individuals with positive QFT-GIT. We also found MLR rather than sodium was independently related to the death risk. Both MLR itself and comprehensive model were all significantly related to the positive QFT-GIT and death risk, which might participate in the initiation and progression of tuberculosis infection.

Accuracy of monocyte to lymphocyte ratio for tuberculosis diagnosis and its role in monitoring anti-tuberculosis treatment: Systematic review and meta-analysis

BACKGROUND

High monocyte to lymphocyte ratio (MLR) values may be associated with the risk of active tuberculosis (TB) infection in adults, infants, and postpartum women with HIV infection. It may also serve as an indicator of the effectiveness of anti-TB treatment. Thus, the main aim of this study is to ascertain the accuracy of MLR for the diagnosis of TB and its role in monitoring the effectiveness of anti-TB therapy.

METHODS

This systematic review and meta-analysis followed the preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. All statistical analyses were performed using STATA 11 and Meta-DiSc software. The Quality assessment of Diagnostic Accuracy Studies tool was used to evaluate the methodological quality of the included studies. The area under the hierarchical summary receiver-operating characteristic hierarchical summary ROC curve [(HSROC) curve (AUC)] was also calculated as an indicator of diagnostic accuracy.

RESULTS

A total of 15 articles were included in this study. Accordingly, the result showed that elevated MLR is associated with increased risks of TB disease [odd ratio = 3.11 (95% CI: 1.40-6.93)]. The pooled sensitivity and specificity of MLR for identifying TB were 79.5% (95% CI: 68.5-87.3) and 80.2% (95% CI: 67.3-88.9), respectively. The AUC of HSROC was 0.88 (95% CI: 0.857-0.903), indicating the excellent diagnostic performance of MLR for TB. This study also showed that there is a significant reduction in the MLR value after anti-TB treatment in TB patients (standardized mean difference  = 0.68; 95% CI: 0.007, 1.43).

CONCLUSIONS

Generally, MLR can be considered as a crucial biomarker to identify TB and monitor the effectiveness of anti-TB therapy.

Development of a Clinical Prediction Score Including Monocyte-to-Lymphocyte Ratio to Inform Tuberculosis Treatment Among Children With HIV: A Multicountry Study

Background

Clinical pediatric tuberculosis (TB) diagnosis may lead to overdiagnosis particularly among children with human immunodeficiency virus (CHIV). We assessed the performance of monocyte-lymphocyte ratio (MLR) as a diagnostic biomarker and constructed a clinical prediction score to improve specificity of TB diagnosis in CHIV with limited access to microbiologic testing.

Methods

We pooled data from cohorts of children aged ≤13 years from Vietnam, Cameroon, and South Africa to validate the use of MLR ≥0.378, previously found as a TB diagnostic marker among CHIV. Using multivariable logistic regression, we created an internally validated prediction score for diagnosis of TB disease in CHIV.

Results

The combined cohort had 601 children (median age, 1.9 [interquartile range, 0.9-5.3] years); 300 (50%) children were male, and 283 (47%) had HIV. Elevated MLR ≥0.378 had sensitivity of 36% (95% confidence interval [CI], 23%-51%) and specificity of 79% (95% CI, 71%-86%) among CHIV in the validation cohort. A model using MLR ≥0.28, age ≥4 years, tuberculin skin testing ≥5 mm, TB contact history, fever >2 weeks, and chest radiograph suggestive of TB predicted active TB disease in CHIV with an area under the receiver operating characteristic curve of 0.85. A prediction score of ≥5 points had a sensitivity of 94% and specificity of 48% to identify confirmed TB, and a sensitivity of 82% and specificity of 48% to identify confirmed and unconfirmed TB groups combined.

Conclusions

Our score has comparable sensitivity and specificity to algorithms including microbiological testing and should enable clinicians to rapidly initiate TB treatment among CHIV when microbiological testing is unavailable.

Latent Tuberculosis Infection in Haematopoietic Stem Cell Transplant Recipients: A Retrospective Italian Cohort Study in Tor Vergata University Hospital, Rome

The results of tuberculosis (TB) screening and reactivation in a cohort of 323 adult patients undergoing haematopoietic stem cell transplantation (HSCT) from 2015 to 2019 at the University Hospital of Tor Vergata, Rome, Italy, were reported. A total of 260 patients, 59 (18.3%) autologous and 264 (81.7%) allogeneic transplants, underwent Interferon Release (IFN)-γ (IGRA) test screening: 228 (87.7%) were negative, 11 (4.2%) indeterminate and 21 (8.1%) positive. Most of the IGRA-positive patients were of Italian origin (95.2%) and significantly older than the IGRA-negative (p < 0.001); 22 (8.5%) patients underwent a second IGRA during the first year after transplantation, and 1 tested positive for IGRA. Significantly lower monocyte (p = 0.044) and lymphocyte counts (p = 0.009) were detected in IGRA negative and IGRA indeterminate patients, respectively. All latent TB patients underwent isoniazid prophylaxis, and none of them progressed to active TB over a median follow-up period of 63.4 months. A significant decline in TB screening practices was shown from 2015 to 2019, and approximately 19% of patients were not screened. In conclusion, 8.1% of our HSCT population had LTBI, all received INH treatment, and no reactivation of TB was observed during the follow-up period. In addition, 19% escaped screening and 8% of these came from countries with a medium TB burden, therefore at higher risk of possible development of TB.

A systematic review on Correlates of Risk of TB disease in children and adults

BACKGROUND

Tuberculosis (TB) remains one of the leading causes of death in the world. Targeted treatment to prevent progression from TB exposure and infection to disease is a key element of WHO End-TB strategy. A systematic review to identify and develop correlates of risk (COR) of TB disease is timely.

METHOD

EMBASE, MEDLINE, PUBMED were searched using relevant keywords and MeSH terms published between 2000 and 2020 on COR of TB disease in children and adults. Preferred Reporting Items for Systematic reviews and Meta-analysis (PRISMA) framework was used for structuring and reporting of outcomes. Risk of bias was assessed using Quality Assessment of Diagnostic Accuracy Studies tool-2 (QUADAS-2).

RESULTS

4105 studies were identified. Following eligibility screening, 27 studies were quality assessed. Risk of bias was high in all studies. Broad variations in COR type, study population, methodology and result reporting were observed. Tuberculin skin test (TST) and interferon gamma release essays (IGRA) are poor COR. Transcriptomic signatures although promising require validation studies to assess wider applicability. Performance consistency of other CORs-cell marker, cytokines and metabolites are much needed.

CONCLUSION

This review identifies the need for a standardized approach to identify a universally applicable COR signature to achieve the WHO END-TB targets.

Single-cell profiling reveals distinct subsets of CD14+ monocytes drive blood immune signatures of active tuberculosis

Introduction

Previous studies suggest that monocytes are an important contributor to tuberculosis (TB)-specific immune signatures in blood.

Methods

Here, we carried out comprehensive single-cell profiling of monocytes in paired blood samples of active TB (ATB) patients at diagnosis and mid-treatment, and healthy controls.

Results

At diagnosis, ATB patients displayed increased monocyte-to-lymphocyte ratio, increased frequency of CD14+CD16- and intermediate CD14+CD16+ monocytes, and upregulation of interferon signaling genes that significantly overlapped with previously reported blood TB signatures in both CD14+ subsets. In this cohort, we identified additional transcriptomic and functional changes in intermediate CD14+CD16+ monocytes, such as the upregulation of inflammatory and MHC-II genes, and increased capacity to activate T cells, reflecting overall increased activation in this population. Single-cell transcriptomics revealed that distinct subsets of intermediate CD14+CD16+ monocytes were responsible for each gene signature, indicating significant functional heterogeneity within this population. Finally, we observed that changes in CD14+ monocytes were transient, as they were no longer observed in the same ATB patients mid-treatment, suggesting they are associated with disease resolution.

Discussion

Together, our study demonstrates for the first time that both intermediate and classical monocytes individually contribute to blood immune signatures of ATB and identifies novel subsets and associated gene signatures that may hold disease relevance.

Single-Cell RNA Sequencing Revealed CD14+ Monocytes Increased in Patients With Takayasu's Arteritis Requiring Surgical Management

Objectives: Takayasu Arteritis (TA) is a highly specific vascular inflammation and poses threat to patients’ health. Although some patients have accepted medical treatment, their culprit lesions require surgical management (TARSM). This study aimed at dissecting the transcriptomes of peripheral blood mononuclear cells (PBMCs) in these patients and to explore potential clinical markers for TA development and progression.

Methods: Peripheral blood were collected from four TA patients requiring surgical management and four age-sex matched healthy donors. Single cell RNA sequencing (scRNA-seq) was adopted to explore the transcriptomic diversity and function of their PBMCs. ELISA, qPCR, and FACS were conducted to validate the results of the analysis.

Results: A total of 29918 qualified cells were included for downstream analysis. Nine major cell types were confirmed, including CD14⁺ monocytes, CD8⁺ T cells, NK cells, CD4⁺ T cells, B cells, CD16⁺ monocytes, megakaryocytes, dendritic cells and plasmacytoid dendritic cells. CD14⁺ monocytes (50.0 vs. 39.3%, p < 0.05) increased in TA patients, as validated by FACS results. TXNIP, AREG, THBS1, and CD163 increased in TA patients. ILs like IL-6, IL-6STP1, IL-6ST, IL-15, and IL-15RA increased in TA group.

Conclusion: Transcriptome heterogeneities of PBMCs in TA patients requiring surgical management were revealed in the present study. In the patients with TA, CD14⁺ monocytes and gene expressions involved in oxidative stress were increased, indicating a new treatment and research direction in this field.

Distinct blood transcriptomic signature of treatment in latent tuberculosis infected individuals at risk of developing active disease

Although only a small fraction will ever develop the active form of tuberculosis (ATB) disease, chemoprophylaxis treatment in latent TB infected (LTBI) individuals is an effective strategy to control pathogen transmission. Characterizing immune responses in LTBI upon chemoprophylactic treatment is important to facilitate treatment monitoring, and thus improve TB control strategies. Here, we studied changes in the blood transcriptome in a cohort of 42 LTBI and 8 ATB participants who received anti-TB therapy. Based on the expression of previously published gene signatures of progression to ATB, we stratified the LTBI cohort in two groups and examined if individuals deemed to be at elevated risk of developing ATB before treatment (LTBI-Risk) differed from others (LTBI-Other). We found that LTBI-Risk and LTBI-Other groups were associated with two distinct transcriptomic treatment signatures, with the LTBI-Risk signature resembling that of treated ATB patients. Notably, overlapping genes between LTBI-Risk and ATB treatment signatures were associated with risk of progression to ATB and interferon (IFN) signaling, and were selectively downregulated upon treatment in the LTBI-Risk but not the LTBI-Other group. Our results suggest that transcriptomic reprogramming following treatment of LTBI is heterogeneous and can be used to distinguish LTBI-Risk individuals from the LTBI cohort at large.

The monocyte-to-lymphocyte ratio: Sex-specific differences in the tuberculosis disease spectrum, diagnostic indices and defining normal ranges

Background

The monocyte-to-lymphocyte ratio (MLR) has been advocated as a biomarker in tuberculosis. Our objective was to evaluate its clinical value and associations.

Methods

Blood counts, inflammatory markers and clinical parameters were measured in patients with and those screened for tuberculosis. Complete blood counts (CBCs) from a multi-ethnic population aged 16 to 65 years were evaluated; a sub-group with normal hematological indices was used to define the range of MLRs.

Results

Multivariate analysis in proven tuberculosis (n = 264) indicated MLR associated with low serum albumin, high white cell counts and a positive culture; values were higher in sputum smear-positive pulmonary tuberculosis (S+PTB). Analysis in S+PTB (n = 296) showed higher MLRs in males and those with high neutrophil counts, low serum albumin and high C-reactive protein. The diagnostic value of MLRs was assessed by comparing notified patients with TB (n = 264) with denotified cases (n = 50), active case-finding in non-contacts (TB n = 111 and LTBI n = 373) and contacts of S+PTB (n = 149) with S+PTB found at screening (n = 75). Sensitivities and specificities ranged from 58.0–62.5% and 50.0–70.0% respectively for optimal cut-off values, defined by ROC curves. In CBCs obtained over one month, ratios correlated with neutrophil counts (ρ = 0.48, P<0.00001, n = 14,573; MLR = 0.45 at 8–8.9 x 10⁹/L) and were higher in males than females (P<0.0001). The MLR range (mean ± 2SD) in those with normal hematological indices (n = 3921: females 0.122–0.474; males 0.136–0.505) paralleled LTBI MLRs. Ratios did not predict death (n = 29) nor response to treatment (n = 178 S+PTB with follow-up CBCs). Ratios were higher in males than female in the 16–45 years age group, where immune differences due to sex hormones are likely greatest.

Conclusions

Severe tuberculosis and male sex associated with high MLRs; the same variables likely affect the performance of other biomarkers. The ratio performed poorly as a clinical aid.

Bovine innate immune phenotyping via a standardized whole blood stimulation assay

Cattle vary in their susceptibility to infection and immunopathology, but our ability to measure and longitudinally profile immune response variation is limited by the lack of standardized immune phenotyping assays for high-throughput analysis. Here we report longitudinal innate immune response profiles in cattle using a low-blood volume, whole blood stimulation system—the ImmunoChek (IChek) assay. By minimizing cell manipulation, our standardized system minimizes the potential for artefactual results and enables repeatable temporal comparative analysis in cattle. IChek successfully captured biological variation in innate cytokine (IL-1β and IL-6) and chemokine (IL-8) responses to 24-hr stimulation with either Gram-negative (LPS), Gram-positive (PamCSK4) bacterial or viral (R848) pathogen-associated molecular patterns (PAMPs) across a 4-month time window. Significant and repeatable patterns of inter-individual variation in cytokine and chemokine responses, as well as consistent high innate immune responder individuals were identified at both baseline and induced levels. Correlation coefficients between immune response read-outs (IL-1β, IL-6 and IL-8) varied according to PAMP. Strong significant positive correlations were observed between circulating monocytes and IL-6 levels for null and induced responses (0.49–0.61) and between neutrophils and cytokine responses to R848 (0.38–0.47). The standardized assay facilitates high-throughput bovine innate immune response profiling to identify phenotypes associated with disease susceptibility and responses to vaccination.

Association between monocyte-to-lymphocyte ratio and tuberculin skin test positivity in HIV-positive adults

BACKGROUND

The tuberculin skin test (TST) identifies individuals at high risk of developing tuberculosis (TB) but poses many challenges. The blood monocyte-to-lymphocyte ratio (MLR) could be an alternative, as extremes in MLR have been associated with increased risk of TB disease.

METHODS

At a primary care clinic in Johannesburg, a differential white blood cell count and TST was performed in adults starting antiretroviral treatment (ART) without symptoms suggestive of active TB.

RESULTS

Of 259 participants, 171 had valid results of whom 30% (51/171) were TST positive and the median MLR was 0.18 (IQR 0.13-0.28). The MLR distribution differed between CD4 count categories (p < 0.01), with a broader range of values in TST negative participants with a low CD4 count (≤ 250 cells/mm3), likely reflecting HIV immunosuppression. MLR was associated with a positive TST (OR 0.78 per 0.1 increase, 95% CI 0.59, 0.97) in bivariate analysis but not in multivariate regression analysis (aOR 0.83 for every 0.1 increase, 95% CI 0.60, 1.08).

CONCLUSION

In ART-naïve adults without symptoms suggestive of active TB, MLR was not independently associated with TST positivity and is thus unlikely to be a useful alternative to TST. Future research should focus on development of a cheap, simple and accurate biomarker to identify those people benefiting most from preventive TB therapy.

Immune status changing helps diagnose osteoarticular tuberculosis

Objective

This study is aimed to develop a new nomogram for the clinical diagnosis of osteoarticular tuberculosis (TB).

Methods

xCell score estimation to obtained the immune cell type abundance scores. We downloaded the expression profile of GSE83456 from GEO and proceed xCell score estimation. The routine blood examinations of 326 patients were collected for further validation. We analyzed univariate and multivariate logistic regression to identified independent predicted factor for developing the nomogram. The performance of the nomogram was assessed using the receiver operating characteristic (ROC) curves. The correlation of ESR with lymphocytes, monocytes, and ML ratio was performed and visualized in osteoarticular TB patients.

Results

Compared with the healthy control group in the dataset GSE83456, the xCell score of basophils, monocytes, neutrophils, and platelets was higher, while lymphoid was lower in the EPTB group. The clinical data showed that the cell count of monocytes were much higher, while the cell counts of lymphocytes were lower in the osteoarticular TB group. AUCs of the nomogram was 0.798 for the dataset GSE83456, and 0.737 for the clinical data. We identified the ML ratio, BMI, and ESR as the independent predictive factors for osteoarticular TB diagnosis and constructed a nomogram for the clinical diagnosis of osteoarticular TB. AUCs of this nomogram was 0.843.

Conclusions

We demonstrated a significant change between the ML ratio of the EPTB and non-TB patients. Moreover, we constructed a nomogram for the clinical diagnosis of the osteoarticular TB diagnosis, which works satisfactorily.

Monocyte-to-lymphocyte ratio as a predictor of stroke-associated pneumonia: A retrospective study-based investigation

BACKGROUND AND PURPOSE

Early prediction of stroke-associated pneumonia (SAP) is significant in clinical practice, as it is frequently challenging due to delays in typical clinical manifestations and radiological changes. The monocyte-to-lymphocyte ratio (MLR) has been proposed as an indicator of systemic inflammation and infection. However, none of these studies have focused on the predictive value of the MLR for SAP. We investigated the predictive value of MLR for SAP and investigated its relationship with disease severity.

METHODS

In this retrospective study, we assessed 399 consecutive patients with acute stroke. SAP was defined according to the modified Centers for Disease Control and Prevention criteria. The severity of pneumonia was rated using the pneumonia severity index (PSI). MLR was calculated by dividing absolute monocyte counts by absolute lymphocyte counts.

RESULTS

Among all the patients, SAP occurred in 116 patients (29.1%). White blood cell (WBC), neutrophil, monocyte, and MLR levels in the SAP group were higher than those in the non-SAP group, while lymphocyte levels were lower (p < .05). Multivariable regression analysis revealed that the MLR (OR = 7.177; 95% CI = 1.190-43.292, p = .032) remained significant after adjusting for confounders. The ROC curve showed that the AUC value of MLR for SAP was 0.779, the optimal cutoff value of MLR for SAP was 0.388, with a specificity of 64.7% and sensitivity of 81.3%. The MLR levels were significantly higher in the severe pneumonia group when assessed by PSI (p = .024) than in the mild group. The AUC value of MLR was 0.622 (95% CI = 0.520-0.724, p = .024) in the severe pneumonia group. The optimal cutoff value of MLR was 0.750, with a specificity of 91.0% and a sensitivity of 33.0%.

CONCLUSIONS

Our study shows that a high MLR is an independent risk factor for SAP and has a predictive value for severe pneumonia in patients with SAP.

Monocyte to high-density lipoprotein cholesterol and lymphocyte to monocyte ratios are predictors of in-hospital and long-term mortality in patients with acute coronary syndrome

OBJECTIVE

We aimed to determine the relationship between LMR and MHR and in-hospital and long-term mortality in patients with ACS.

METHODS

We retrospectively collected patients with ACS undergoing coronary angiography between January 2012 and December 2013.

RESULTS

In total, 825 patients with a mean age of 62.4 ± 12.9 years (71.3% male) were enrolled in the study. Patients were divided into three tertiles based on MHR levels and LMR levels. In-hospital mortality of the patients was significantly higher amongst patients in the upper MHR tertile when compared with the lower and middle MHR tertile groups [30 (10.9%) vs 8 (2.9%) and 14 (5.1%); P < .001, P = .009, respectively]. Five-year mortality of the patients was significantly higher amongst patients in the upper MHR tertile when compared with the lower and middle MHR tertile groups [84 (30.5%) vs 48 (17.5%) and 57 (20.7%); P < .001, P = .005, respectively]. In-hospital mortality of the patients was significantly higher amongst patients in the lower LMR tertile when compared with the upper and middle LMR tertile groups [25 (9.1%) vs 10 (3.6%) and 17 (6.2%); P = .007, P = .130, respectively]. Five -year mortality of the patients was significantly higher amongst patients in the lower LMR tertile when compared with the upper and middle LMR tertile groups [77 (28.0%) vs 47 (17.1%) and 65 (23.6%); P = .001, P = .142, respectively].

CONCLUSION

We have shown that high MHR and low LMR were significant and independent predictors of in-hospital and long-term mortality in patients with ACS.

Elevated Monocyte to Lymphocyte Ratio and Increased Mortality among Patients with Chronic Kidney Disease Hospitalized for COVID-19

Chronic kidney disease (CKD) constitutes a major health problem and one of the leading causes of death worldwide. Patients with CKD have impaired immune functions that predispose them to an increased risk of infections, as well as virus-associated cancers and a diminished vaccine response. In this study, we aimed to identify clinical and laboratory parameters associated with in-hospital mortality in patients evaluated in the department of emergency (ER) and admitted with the diagnosis of severe acute respiratory syndrome (SARS) caused by coronavirus disease 2019 (COVID-19) at the Baptist Hospital of Nicaragua (BHN). There were 37 patients with CKD, mean age 58.3 ± 14.1 years, admitted to BHN due to COVID-19, and among them, 24 (65.7%) were males (p = 0.016). During hospitalization, 23 patients with CKD (62.1%) died of complications associated with COVID-19 disease, which was a higher proportion (odds ratio (OR) 5.6, confidence interval (CI) 2.1-15.7, p = 0.001) compared to a group of 70 patients (64.8% males, mean age 57.5 ± 13.7 years) without CKD admitted during the same period in whom 28.5% died of COVID-19. In the entire cohort, the majority of patients presented with bilateral pneumonia, and the most common symptoms at admission were dyspnea, cough, and fever. Serum levels of D-dimer, ferritin and procalcitonin were significantly higher in patients with CKD compared with those without CKD. Multivariate analysis revealed that CKD, age (>60 years), and hypoxia measured in the ER were factors associated with increased in-hospital mortality. Among patients with CKD but not in those without CKD (OR 36.8, CI 1.5-88.3, p = 0.026), an increased monocytes-to-lymphocyte ratio (MLR) was associated with higher mortality and remained statistically significant after adjusting for confounders. The MLR measured in the ER may be useful for predicting in-hospital mortality in patients with CKD and COVID-19 and could contribute to early risk stratification in this group.

Nonlethal Plasmodium yoelii Infection Drives Complex Patterns of Th2-Type Host Immunity and Mast Cell-Dependent Bacteremia

Malaria strongly predisposes to bacteremia, which is associated with sequestration of parasitized red blood cells and increased gastrointestinal permeability. The mechanisms underlying this disruption are poorly understood. Here, we evaluated the expression of factors associated with mast cell activation and malaria-associated bacteremia in a rodent model. C57BL/6J mice were infected with Plasmodium yoeliiyoelli 17XNL, and blood and tissues were collected over time to assay for circulating levels of bacterial 16S DNA, IgE, mast cell protease 1 (Mcpt-1) and Mcpt-4, Th1 and Th2 cytokines, and patterns of ileal mastocytosis and intestinal permeability.

Malaria strongly predisposes to bacteremia, which is associated with sequestration of parasitized red blood cells and increased gastrointestinal permeability. The mechanisms underlying this disruption are poorly understood. Here, we evaluated the expression of factors associated with mast cell activation and malaria-associated bacteremia in a rodent model. C57BL/6J mice were infected with Plasmodium yoeliiyoelli 17XNL, and blood and tissues were collected over time to assay for circulating levels of bacterial 16S DNA, IgE, mast cell protease 1 (Mcpt-1) and Mcpt-4, Th1 and Th2 cytokines, and patterns of ileal mastocytosis and intestinal permeability. The anti-inflammatory cytokines (interleukin-4 [IL-4], IL-6, and IL-10) and MCP-1/CCL2 were detected early after P. yoeliiyoelii 17XNL infection. This was followed by the appearance of IL-9 and IL-13, cytokines known for their roles in mast cell activation and growth-enhancing activity as well as IgE production. Later increases in circulating IgE, which can induce mast cell degranulation, as well as Mcpt-1 and Mcpt-4, were observed concurrently with bacteremia and increased intestinal permeability. These results suggest that P. yoeliiyoelii 17XNL infection induces the production of early cytokines that activate mast cells and drive IgE production, followed by elevated IgE, IL-9, and IL-13 that maintain and enhance mast cell activation while disrupting the protease/antiprotease balance in the intestine, contributing to epithelial damage and increased permeability.

Can monocyte to HDL cholesterol ratio and monocyte to lymphocyte ratio be markers for inflammation and oxidative stress in patients with vitiligo? A preliminary study

Both systemic inflammation and oxidative stress play crucial roles in the pathogenesis of vitiligo. In recent studies, monocyte to high-density lipoprotein cholesterol ratio (MHR), monocyte to lymphocyte ratio (MLR), neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), mean platelet volume (MPV) and plateletcrit (PCT) have been shown to reflect inflammation and oxidative stress in chronic inflammatory and autoimmune diseases. In this study, we aimed to investigate the hematological and inflammatory parameters in patients with vitiligo and to evaluate their possible relationship with disease severity. The parameters including MHR, MLR, NLR, PLR, MPV, and PCT were retrospectively investigated in patients with vitiligo and healthy controls. Disease severity was evaluated using the vitiligo extent tensity index (VETI) score. A total of 180 patients with vitiligo, and age-gender-matched 180 healthy controls were enrolled in the study. MHR, MLR, PLR, PCT values were found to be significantly higher in patients with vitiligo (p < 0.05). MPV and NLR values showed no statistically significant difference between the two groups. A positive correlation was also detected between MHR and MLR values, disease duration, and VETI score (p < 0.05). We suggest that MHR and MLR can be used as markers of inflammation and oxidative stress in patients with vitiligo. Both markers may also reflect disease severity.

The potential of CBC-derived ratios (monocyte-to-lymphocyte, neutrophil-to-lymphocyte, and platelet-to-lymphocyte) to predict or diagnose incident TB infection in Tanzanian adolescents

Background

Ratios of different immune cell populations (i.e., monocyte-to-lymphocyte, neutrophil-to-lymphocyte, and platelet-to-lymphocyte ratios) have been studied as a means of predicting future tuberculosis (TB) disease risk or to assist in the diagnosis of incident TB disease. No studies to-date, however, have evaluated the potential of these ratios to predict or assist in the diagnosis of incident TB infection - the first step in the natural history of TB disease.

Methods

In this prospective study, we evaluated the complete blood count (CBC)-derived metrics of monocyte-to-lymphocyte ratio (MLR), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) as predictors of future TB infection risk or aids in the diagnosis of TB infection among 145 Tanzanian adolescents enrolled in the DAR-901 vaccine trial, using paired CBCs and interferon-gamma release assays (IGRAs) obtained at 0, 60 and 720 days after study enrollment.

Results

At baseline, there were no significant differences between study participants who remained persistently IGRA negative throughout the study period and those who subsequently converted to IGRA positive with respect to MLR (0.18 vs 0.17, p = 0.10), NLR (0.88 vs 1.02, p = 0.08), or PLR (115 vs 120, p = 0.28). Similarly, no significant differences were noted with respect to MLR, NLR, and PLR between IGRA converters and time-matched negative controls at the time of IGRA conversion. With respect to other blood cell measures, however, there were modest but significant differences between IGRA negatives and IGRA converters with respect to red blood cell count (4.8 vs 4.6 ×  10⁶ cells/mcL, p = 0.008), hemoglobin (12.6 vs 12.3 g/dL, p = 0.01), and hematocrit (38.8 vs 37.8%, p = 0.005).

Conclusions

In contrast to prior studies that have suggested that the ratios of different immune cell populations are associated with development of TB disease, our present findings do not demonstrate an association between these ratios and the development of TB infection. However, decreased red blood cell measures were associated with the subsequent development of TB infection, suggesting either that dysregulation of iron metabolism may play a role in TB pathogenesis or that following TB infection, iron dysregulation may precede IGRA positivity.

Trial registration

Clinicaltrials.gov NCT02712424. Date of registration: March 14, 2016.

Can decreased monocyte to HDL-cholesterol ratio be a marker indicating the anti-inflammatory effect of the colchicine in Behçet's disease? A preliminary study

Behçet's disease (BD) is an auto-inflammatory disease characterized by systemic vasculitis. Monocyte to HDL-cholesterol ratio (MHR), monocyte to lymphocyte ratio (MLR), and neutrophil to lymphocyte ratio (NLR) are used as inflammatory markers in many disorders. Colchicine decreases inflammation by suppressing the secretion of pro-inflammatory cytokines. This study aims to examine the effects of colchicine treatment on MHR, MLR, and NLR levels of the patients with BD. In this study, 80 patients, who were with mild/moderate/severe BD based on the Krause's Clinical Severity Scoring for BD and received colchicine treatment for at least 3 months, were evaluated retrospectively. The results of MHR, MLR, NLR, and other hematological parameters were assessed in three groups as follows: precolchicine treatment (Group 1), at the end of the 1st month of the treatment (Group 2), and at the end of the 3rd month of the treatment (Group 3). A total of 80 patients involving 39 (48.75%) females and 41 (51.25%) males, who were treated with colchicine due to the diagnosis of BD, were examined in this study. The mean age of the patients was 36.85 ± 10.659 (18-59) years. The findings showed that there was a statistically significant reduction in MHR, MLR, and NLR levels of postcolchicine treatment (P = .0004, P = .0007, and P = .0003, respectively). MHR level was 0.015 ± 0.005 in Group 1, 0.013 ± 0.004 in Group 2, 0.011 ± 0.004 in Group 3, while MLR level was 0.346 ± 0.131 in Group 1, 0.277 ± 0.098 in Group 2, 0.229 ± 0.08 in Group 3, and NLR level was 2.528 ± 0.999 in Group 1, 2.001 ± 0.672 in Group 2, 1.704 ± 0.619 in Group 3. A significant association was found between the MHR value of pretreatment and the clinical severity of BD (P = .04). The findings obtained in this study suggest that we can determine the anti-inflammatory impact of colchicine in BD using MHR, MLR, and NLR markers, and MHR can also be a potential index for assessing the disease activity of BD.

High-throughput analysis of T cell-monocyte interaction in human tuberculosis

The lack of efficient tools for identifying immunological correlates of tuberculosis (TB) protection or risk of disease progression impedes the development of improved control strategies. To more clearly understand the host response in TB, we recently established an imaging flow cytometer‐based in‐vitro assay, which assesses multiple aspects of T cell–monocyte interaction. Here, we extended our previous work and characterized communication between T cells and monocytes using clinical samples from individuals with different TB infection status and healthy controls from a TB endemic setting. To identify T cell–monocyte conjugates, peripheral blood mononuclear cells (PBMC) were stimulated with ds‐Red‐expressing Mycobacterium bovis bacille Calmette–Guérin or 6‐kDa early secreted antigenic target (ESAT 6) peptides for 6 h, and analyzed by imaging flow cytometer (IFC). We then enumerated T cell–monocyte conjugates using polarization of T cell receptor (TCR) and F‐actin as markers for synapse formation, and nuclear factor kappa B (NF‐κB) nuclear translocation in the T cells. We observed a reduced frequency of T cell–monocyte conjugates in cells from patients with active pulmonary tuberculosis (pTB) compared to latent TB‐infected (LTBI) and healthy controls. When we monitored NF‐κB nuclear translocation in T cells interacting with monocytes, the proportion of responding cells was significantly higher in active pTB compared with LTBI and controls. Overall, these data underscore the need to consider multiple immunological parameters against TB, where IFC could be a valuable tool.

Neutrophil-to-Monocyte-Plus-Lymphocyte Ratio as a Potential Marker for Discriminating Pulmonary Tuberculosis from Nontuberculosis Infectious Lung Diseases

OBJECTIVE

To determine whether NMLR has more statistical strength than NLR in discriminating TB from non-TB infectious lung diseases.

METHODS

Among patients who underwent 3 or more TB culture tests with molecular study between January 2016 and December 2017, 110 patients with TB, and 159 patients diagnosed with non-TB infectious lung diseases were enrolled. The original complete blood count (CBC) parameters and modified CBC indices, including NLR and NMLR, were analyzed.

RESULTS

The NLR and NMLR were significantly lower in TB patients than in patients with other infectious lung diseases. However, the area under the curve (AUC) for NMLR (0.90; 95% confidence interval [CI], 0.86-0.93) was significantly greater than that for NLR (0.88 [0.84-0.92]).

CONCLUSIONS

The neutrophil-to-monocyte-plus-lymphocyte ratio (NMLR) can be used as a new index that is more powerful than neutrophil-to-lymphocyte ratio (NLR) in discriminating tuberculosis (TB) from non-TB infectious lung diseases.NMLR had more statistical strength than NLR in discriminating TB from non-TB infectious lung diseases.

Disparate Tuberculosis Disease Development in Macaque Species Is Associated With Innate Immunity

While tuberculosis continues to afflict mankind, the immunological mechanisms underlying TB disease development are still incompletely understood. Advanced preclinical models for TB research include both rhesus and cynomolgus macaques (Macaca mulatta and Macaca fascicularis, respectively), with rhesus typically being more susceptible to acute progressive TB disease than cynomolgus macaques. To determine which immune mechanisms are responsible for this dissimilar disease development, we profiled a broad range of innate and adaptive responses, both local and peripheral, following experimental pulmonary Mycobacterium tuberculosis (Mtb) infection of both species. While T-cell and antibody responses appeared indistinguishable, we identified anti-inflammatory skewing of peripheral monocytes in rhesus and a more prominent local pro-inflammatory cytokine release profile in cynomolgus macaques associated with divergent TB disease outcome. Importantly, these differences were detectable both before and early after infection. This work shows that inflammatory and innate immune status prior to and at early stages after infection, critically affects outcome of TB infection.

Monocyte-to-Lymphocyte Ratio Is Associated With Tuberculosis Disease and Declines With Anti-TB Treatment in HIV-Infected Children

BACKGROUND

The blood monocyte-to-lymphocyte ratio (MLR) is associated with active tuberculosis (TB) in adults but has not been evaluated as a TB diagnostic biomarker in HIV-infected children in whom respiratory sampling is difficult.

SETTING

In a cohort of HIV-infected hospitalized Kenyan children initiating antiretroviral therapy, absolute monocyte and lymphocyte counts were determined at enrollment and 4, 12, and 24 weeks thereafter.

METHODS

Children were classified as confirmed, unconfirmed, or unlikely pulmonary TB. Receiver operating characteristic curves of MLR cutoff values were generated to distinguish children with confirmed TB from those with unconfirmed and unlikely TB. General estimating equations were used to estimate change in the MLR over time by TB status.

RESULTS

Of 160 children with median age 23 months, 13 (8.1%) had confirmed TB and 67 (41.9%) had unconfirmed TB. The median MLR among children with confirmed TB {0.407 [interquartile range (IQR) 0.378-0.675]} was higher than the MLR in children with unconfirmed [0.207 (IQR 0.148-0.348), P < 0.01] or unlikely [0.212 (IQR 0.138-0.391), P = 0.01] TB. The MLR above 0.378 identified children with confirmed TB with 77% sensitivity, 78% specificity, 24% positive predictive value, and 97% negative predictive value. After TB treatment, the median MLR declined in children with confirmed TB and levels were similar to children with unlikely TB after 12 weeks.

CONCLUSIONS

The blood MLR distinguished HIV-infected children with confirmed TB from those with unlikely TB and declined with TB treatment. The MLR may be a useful diagnostic tool for TB in settings where respiratory-based microbiologic confirmation is inaccessible.

Monocyte/lymphocyte ratio is associated with carotid stenosis in ischemic stroke: A retrospective analysis

BACKGROUND

Carotid artery stenosis, mainly caused by carotid atherosclerosis, is related to ischemic stroke. This study was to investigate whether monocyte/lymphocyte ratio (MLR) was associated with increased severity of carotid stenosis in patients with ischemic stroke.

METHODS

A total of 395 participants with ischemic stroke were retrospectively analyzed. The severity of carotid stenosis was evaluated by ultrasound examination. Patients were divided into two groups: nonsevere stenosis group and severe stenosis group. Multivariate logistic analysis was used to evaluate risk factors.

RESULTS

A significant correlation was found between MLR and the severity of carotid stenosis in patients with ischemic stroke. MLR was the independent risk factor of carotid stenosis (OR: 9.74, 95% CI: 1.16-81.54). In the ROC curves analysis, a cutoff value of 0.20 for MLR predicted the severity of carotid stenosis with a sensitivity of 80.40% and specificity of 26.40% (ROC area under the curve: 0.598, 95% CI: 0.53-0.67, p = .004).

CONCLUSION

Monocyte/lymphocyte ratio plays important roles in carotid stenosis in patients with ischemic stroke and is an independent risk factor of the severity of carotid stenosis. Therefore, MLR might be considered a potential index in the diagnosis of carotid stenosis in patients with ischemic stroke.

Impact of individual-level factors on Ex vivo mycobacterial growth inhibition: Associations of immune cell phenotype, cytomegalovirus-specific response and sex with immunity following BCG vaccination in humans

Understanding factors associated with varying efficacy of Bacillus Calmette-Guérin (BCG) would aid the development of improved vaccines against tuberculosis (TB). In addition, investigation of individual-level factors affecting mycobacterial-specific immune responses could provide insight into confounders of vaccine efficacy in clinical trials. Mycobacterial growth inhibition assays (MGIA) have been developed to assess vaccine immunogenicity ex vivo and provide a measure of immune function against live mycobacteria. In this study, we assessed the impact of immune cell phenotype, cytomegalovirus (CMV)-specific response and sex on ex vivo growth inhibition following historical BCG vaccination in a cohort of healthy individuals (n = 100). A higher frequency of cytokine-producing NK cells in peripheral blood was associated with enhanced ex vivo mycobacterial growth inhibition following historical BCG vaccination. A CMV-specific response was associated with T-cell activation, a risk factor for TB disease and we also observed an association between T-cell activation and ex vivo mycobacterial growth. Interestingly, BCG-vaccinated females in our cohort controlled mycobacterial growth better than males. In summary, our present study has shown that individual-level factors influence capacity to control mycobacterial growth following BCG vaccination and the MGIA could be used as a tool to assess how vaccine candidates may perform in different populations.

Predicting the risk of pulmonary tuberculosis based on the neutrophil-to-lymphocyte ratio at TB screening in HIV-infected individuals

Background

The neutrophil to lymphocyte ratio (NL ratio) has been reported to be a predictive biomarker of tuberculosis (TB). We assessed the association between the NL ratio and the incidence of active TB cases within 1 year after TB screening among HIV-infected individuals in Thailand.

Methods

A day care center that supports HIV-infected individuals in northernmost Thailand performed TB screening and follow-up visits. We compared the baseline characteristics between the TB screening positive group and the TB screening negative group. The threshold value of NL ratio was determined by cubic-spline curves and NL ratios were categorized as high or low NL ratio. We assessed the association between NL ratio and progression to active TB within 1-year using the Cox-proportional hazard model.

Results

Of the 1064 HIV-infected individuals who screened negative for TB at baseline, 5.6% (N = 60) eventually developed TB and 26 died after TB diagnosis. A high NL ratio was associated with a higher risk of TB (adjusted hazard ratio (aHR) 2.19, 95% CI: 1.23–3.90), after adjusting for age, sex, ethnicity, CD4 counts, and other risk factors. A high NL ratio in HIV-infected individuals with normal chest X-ray predicted TB development risk. In particular, a high NL ratio with TB symptoms could predict the highest risk of TB development (aHR 2.58, 95%CI: 1.07–6.23).

Conclusions

Our results showed that high NL ratio increased the risk of TB. NL ratio combined with TB symptoms could increase the accuracy of TB screening among HIV-infected individuals.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-4292-9) contains supplementary material, which is available to authorized users.

Monocyte/lymphocyte ratio is related to the severity of coronary artery disease and clinical outcome in patients with non-ST-elevation myocardial infarction

Monocyte/lymphocyte ratio (MLR), a widely used inflammation maker for prognosis of cancer, tuberculosis, and autoimmune diseases, has attracted more and more attention for its application to cardiovascular disease. The aim of the present study was to investigate the relationship of MLR with the severity of coronary lesion and clinical outcomes in non-ST-elevation myocardial infarction (NSTEMI) patients.963 consecutive NSTEMI patients (mean age, 60.77 ± 11.34; 758 male) undergoing coronary angiography were analyzed and followed in 3 groups according to the average MLR tertile (low MLR <0.23, n = 321; intermediate MLR 0.23-0.35, n = 322; high MLR >0.35, n = 320) in this study. The severity of coronary lesion was determined by Gensini score. Multiple linear regression analysis was used to examine the correlation between MLR and the severity of coronary lesion. Kaplan-Meier curve was performed to compare the long-term major adverse cardiac event (MACE)-free survival. Logistic regression analysis and Cox proportional hazard regression model were used to assess the independent predictors for in-hospital and long-term MACE.MLR (B: 0.281, 95% confidence interval [CI]: 0.130-0.432, P < .001) and high-sensitivity C-reactive protein (B: 0.017, 95% CI: 0.010-0.024, P < .001) were both independently correlated with the severity of coronary lesion, while neutrophil/lymphocyte ratio was not. The frequencies of in-hospital MACE (1.6%, 2.2%, 4.7%, P = .016) and long-term MACE (13.3%, 16.2%, 27.2%, P < .001) both increased among the 3 groups. Kaplan-Meier curve analysis indicated that patients in high MLR group had worse long-term MACE-free survival than the patients in low MLR group (P2 < .001) and intermediate MLR group (P3 = .004) during a median follow-up of 22 (12-35) months. MLR was an independent predictor for in-hospital MACE (adjusted odds ratio: 2.891, 95% CI: 1.265-8.354, P = .026) and long-term MACE (adjusted hazard ratio: 1.793, 95% CI: 1.169-2.515, P = .012) in NSTEMI patients.MLR is independently correlated with the severity of coronary lesion and has better performance to reflect the severity of coronary lesion than NLR. MLR is an independent predictor for the MACE in NSTEMI patients.

Value of the Ratio of Monocytes to Lymphocytes for Monitoring Tuberculosis Therapy

Objective

The objective of this study was to evaluate the change of the ratio of monocytes to lymphocytes in patients with active tuberculosis, such as to provide reference for clinical diagnosis and treatment.

Methods

All data were collected from the clinical database of The Fifth People's Hospital of Taiyuan, China. A total of 151 patients who had newly diagnosed active tuberculosis with tuberculosis therapy in hospital and 129 healthy controls were selected.

Results

Median ratio of monocytes to lymphocytes was 0.45 (IQR: 0.28–0.67) in patients before treatment and 0.32 (IQR: 0.25–0.46) on discharge (P < 0.001).

Conclusions

Ratio of monocytes to lymphocytes may be applied in diagnosis and the chemotherapeutic efficacy of active tuberculosis.

Differences in monocyte: lymphocyte ratio and Tuberculosis disease progression in genetically distinct populations of macaques

Monocyte:lymphocyte ratio (M:L) has been identified as a risk factor in development of TB disease in children and those undergoing treatment for HIV in co-infected individuals. Retrospective analysis was performed using M:L data collected from TB modelling studies performed in Rhesus macaques of Indian genotype (RM), cynomolgus macaque of Chinese genotype (CCM) and cynomolgus macaque of Mauritian genotype (MCM), which found that the more susceptible populations (RM and MCM) had higher M:L ratios than the least susceptible population (CCM). Following Mycobacterium tuberculosis exposure, significant increases in M:L ratio were observed in susceptible RM and MCM within 12 weeks of TB infection, whereas M:L in CCM remained stable, suggesting that changes in M:L ratio may also act as a biomarker of TB disease progression. The frequency of PPD-specific interferon gamma (IFNγ) secreting cells (SFU) were compared, with the more susceptible macaque populations showing an association between M:L and IFNγ SFU frequency. Investigation of the genes associated with monocyte-derived antigen presenting cells revealed differences between RM and CCM, highlighting differences in their monocyte populations, as well as overall M:L ratio. Differences in M:L ratio between macaque populations could be used to explore immunological mechanisms in susceptible populations that would complement human population studies.

Tuberculosis susceptibility and protection in children

Children represent both a clinically important population susceptible to tuberculosis and a key group in whom to study intrinsic and vaccine-induced mechanisms of protection. After exposure to Mycobacterium tuberculosis, children aged under 5 years are at high risk of progressing first to tuberculosis infection, then to tuberculosis disease and possibly disseminated forms of tuberculosis, with accompanying high risks of morbidity and mortality. Children aged 5-10 years are somewhat protected, until risk increases again in adolescence. Furthermore, neonatal BCG programmes show the clearest proven benefit of vaccination against tuberculosis. Case-control comparisons from key cohorts, which recruited more than 15 000 children and adolescents in total, have identified that the ratio of monocytes to lymphocytes, activated CD4 T cell count, and a blood RNA signature could be correlates of risk for developing tuberculosis. Further studies of protected and susceptible populations are necessary to guide development of novel tuberculosis vaccines that could facilitate the achievement of WHO's goal to eliminate deaths from tuberculosis in childhood.

Prevention of tuberculosis infection and disease by local BCG in repeatedly exposed rhesus macaques

Tuberculosis (TB) remains the deadliest infectious disease¹, and the widely used Bacillus Calmette-Guérin (BCG) vaccine fails to curb the epidemic. An improved vaccination strategy could provide a cost-effective intervention to break the transmission cycle and prevent antimicrobial resistance^2,3. Limited knowledge of the host responses critically involved in protective immunity hampers the development of improved TB vaccination regimens. Therefore, assessment of new strategies in preclinical models to select the best candidate vaccines before clinical vaccine testing remains indispensable. We have previously established in rhesus macaques (Macaca mulatta) that pulmonary mucosal BCG delivery reduces TB disease where standard intradermal injection fails^4,5. Here, we show that pulmonary BCG prevents infection by using a repeated limiting-dose Mycobacterium tuberculosis challenge model and identify polyfunctional T-helper type 17 (T_H17) cells, interleukin-10 and immunoglobulin A as correlates of local protective immunity. These findings warrant further research into mucosal immunization strategies and their translation to clinical application to more effectively prevent the spread of TB.

Paradigm changing evidence that alter tuberculosis perception and detection: Focus on latency

Tuberculosis remains a devastating disease to Mankind, ranking as the ninth cause of death worldwide. Eliminating tuberculosis as proven much more difficult than once anticipated. In addition to the delay in diagnosis and drug resistance problems that compromise the efficacy of treatment, the enormous reservoir of latently infected individuals continuously feeds the epidemics. However, targeting latency with prophylactic antibiotic administration is not possible at the populational level. Together, these issues call for a better understanding of latency, as well as for a more precise identification of individuals at high risk of reactivation. For this, recent paradigm changing evidence need to be taken into account, most notably, the existence of a tuberculosis spectrum; the genetic diversity of both humans and tuberculosis-causing bacteria; and the changes in the human population that interfere with tuberculosis. Here we discuss latency in the light of these variables and how that understanding can move forward tuberculosis research and elimination.

Current approaches toward identifying a correlate of immune protection from tuberculosis

INTRODUCTION

Mycobacterium tuberculosis kills more people than any other pathogen. Vaccination is the most cost-effective control measure for any infectious disease. Development of an effective vaccine against tuberculosis is hindered by the uncertain predictive value of preclinical animal models, incomplete understanding of protective immunity and lack of validated immune correlates of protection (COP).

AREAS COVERED

Here we review what is known about protective immunity against M.tb, the preclinical and clinical cohorts that can be utilized to identify COP, and COP that have been identified to date.

EXPERT COMMENTARY

The identification of COP would allow the rational design and development of vaccine candidates which can then be optimized and prioritized based on the induction of these immune responses. Once validated in field efficacy trials, such COP could potentially facilitate the development and licensure of vaccines, in combination with human efficacy data. The identification and validation of COP would represent a very significant advance in TB vaccine development. Every opportunity to collect samples and cohorts on which to cross-validate pre-existing COP and identify novel COP should be exploited. Furthermore, global cooperation and collaboration on such samples will ensure that the utility of such precious samples is fully exploited.

Assessing the outcome of patients with liver cirrhosis during hospital stay: A comparison of lymphocyte/monocyte ratio with MELD and Child-Pugh scores

BACKGROUND/AIMS

Developing an easy and reliable score for evaluating the prognosis of patients with liver cirrhosis has always been challenging for hepatologists. This study aimed to assess the lymphocyte-to-monocyte ratio (LMR) in comparison with the Model for End-Stage Liver Disease (MELD) and Child-Pugh (CP) scores for determining the outcomes in these patients during hospital stay.

MATERIALS AND METHODS

Receiver operator characteristic (ROC) curve was used to assess the efficacy of three parameters (LMR and MELD and CP scores) in determining the outcomes in 182 patients with cirrhosis. The cutoff values were calculated using Youden index, and the area under the curves (AUCs) was also compared. The associations of these scores between the survived and nonsurvived group was studied. The predictors of patient survival were determined using logistic regression analysis.

RESULTS

The mean values for LMR and MELD and CP scores were 6.23, 11.62, and 9.32, respectively. MELD and CP were positively correlated with each other. LMR was negatively correlated to both MELD and CP scores (p=0.04). Pairwise comparison showed that the difference between the AUCs of MELD and LMR was not statistically significant (0.958 vs. 0.807; p > 0.05). With the LMR cutoff value of > 3.31 (sensitivity, 80%; specificity, 74.83%), patients were segregated into low and high LMR groups. MELD and CP scores were significantly higher in the low LMR group than in the high LMR group (p=0.000). Patients in the low LMR group showed decreased survival than those in the high LMR group (p=0.000). The nonsurvived group had lower LMR and higher MELD and CP scores than those of the survived group (p=0.000). Logistic regression model showed MELD (p=0.000), CP score (p=0.010), 1/LMR (p=0.004), alanine aminotransferase (ALT) level (p=0.010), and international normalized ratio (INR; p=0.043) as predictors of outcome of these patients.

CONCLUSION

LMR can be used to determine the outcome of patients during hospital stay, because it is easy to calculate and can be interpreted with efficacy nearly equal to those of MELD and CP scores.

Systems approaches to correlates of protection and progression to TB disease

Tuberculosis (TB) is the leading cause of death due to a single infectious disease and an effective vaccine would substantially accelerate global efforts to control TB. An immune correlate of protection (CoP) from TB disease could aid vaccine optimization and licensure. This paper summarises opportunities for identifying CoP and highlights results from correlates of risk studies. Although we don't have CoP, there are ongoing efficacy trials with both disease and infection endpoints which provide opportunities for such an analysis. Transcriptomics has successfully identified robust CoR, with transcripts found in the Type I IFN pathway. Correlates of lower risk include BCG antigen specific IFN-γ and natural killer cells. Collating evidence from multiple studies using a range of systems approaches supports a role for IFN-γ in protection from TB disease. In addition, the cells that express the IFN-γ receptor are also important in protective immunity. Protection is a culmination not only of the amount of IFN-γ produced by T cells and NK cells but by the ability of IFN-γ receptor expressing monocytes to respond to IFN-γ. To better understand IFN-γ as a correlate we need to understand host-factors such as age, sex, co-infection, nutritional status and stress which may alter or impair the ability of cells to respond to IFN-γ. These studies highlight recent advances in our understanding of the immune mechanisms of TB disease risk and show the importance of whole systems approaches to correlates of risk analysis. CoP may be useful tools for specific vaccine products in specific populations, but a well-designed CoR analysis can identify novel immune mechanisms and provide insights critical for the development of new and better TB vaccines.

Monocyte Subsets: Phenotypes and Function in Tuberculosis Infection

Monocytes are critical defense components that play an important role in the primary innate immune response. The heterogeneous nature of monocytes and their ability to differentiate into either monocyte-derived macrophages or monocyte-derived dendritic cells allows them to serve as a bridge between the innate and adaptive immune responses. Current studies of monocytes based on immunofluorescence, single-cell RNA sequencing and whole mass spectrometry finger printing reveals different classification systems for monocyte subsets. In humans, three circulating monocyte subsets are classified based on relative expression levels of CD14 and CD16 surface proteins, namely classical, intermediate and non-classical subsets. Transcriptomic analyses of these subsets help to define their distinct functional properties. Tuberculosis (TB) is a disease instigated by the deadly pathogen Mycobacterium tuberculosis. Current research on monocytes in TB has indicated that there are alterations in the frequency of intermediate and non-classical subsets suggesting their impact in bacterial persistence. In this review, we will focus on these monocyte subsets, including their classification, frequency distribution, cytokine profiles, role as a biomarker and will comment on future directions for understanding the salient phenotypic and functional properties relevant to TB pathogenesis.

Altered monocyte phenotypes but not impaired peripheral T cell immunity may explain susceptibility of the elderly to develop tuberculosis

Tuberculosis (TB) is the leading killer due to a single infectious disease worldwide. With the aging of the global population, the case rate and deaths due to TB are highest in the elderly population. While general immunosenescence associated with old age is thought to contribute to the susceptibility of the elderly to develop active TB disease, very few studies of immune function in elderly individuals with Mycobacterium tuberculosis (M.tb) infection or disease have been performed. In particular, impaired adaptive T cell immunity to M.tb is one proposed mechanism for the elderly's increased susceptibility primarily on the basis of the decreased delayed type hypersensitivity response to tuberculin-purified protein derivative in the skin of elderly individuals. To investigate immunological reasons why the elderly are susceptible to develop active TB disease, we performed a cross-sectional observational study over a five year period (2012-2016) enrolling participants from 2 age groups (adults: 25-44 years; elderly: 65 and older) and 3 M.tb infection statuses (active TB, latent TB infection, and healthy controls without history of M.tb infection). We hypothesized that impaired peripheral T cell immunity plays a role in the biological susceptibility of the elderly to TB. Contrary to our hypothesis, we observed no evidence of impaired M.tb specific T cell frequency or altered production of cytokines implicated in M.tb control (IFN-γ, IL-10) in peripheral blood in the elderly. Instead, we observed alterations in monocyte proportion and phenotype with age and M.tb infection that suggest their potential role in the susceptibility of the elderly to develop active TB. Our results suggest a potential link between the known widespread low-grade systemic inflammation of old age, termed "inflammaging," with the elderly's specific susceptibility to developing active TB. Moreover, our results highlight the need for further research into the biological reasons why the elderly are more susceptible to disease and death from TB, so that public health systems can be better equipped to face the present and future problem of TB in an aging global population.

High monocyte to lymphocyte ratio is associated with impaired protection after subcutaneous administration of BCG in a mouse model of tuberculosis

Background: The only available tuberculosis (TB) vaccine, Bacillus Calmette-Guérin (BCG), has variable efficacy. New vaccines are therefore urgently needed. Why BCG fails is incompletely understood, and the tools used for early assessment of new vaccine candidates do not account for BCG variability. Taking correlates of risk of TB disease observed in human studies and back-translating them into mice to create models of BCG variability should allow novel vaccine candidates to be tested early in animal models that are more representative of the human populations most at risk. Furthermore, this could help to elucidate the immunological mechanisms leading to BCG failure. We have chosen the monocyte to lymphocyte (ML) ratio as a correlate of risk of TB disease and have back-translated this into a mouse model. Methods: Four commercially available, inbred mouse strains were chosen. We investigated their baseline ML ratio by flow cytometry; extent of BCG-mediated protection from Mtb infection by experimental challenge; vaccine-induced interferon gamma (IFNγ) response by ELISPOT assay; and tissue distribution of BCG by plating tissue homogenates. Results: The ML ratio varied significantly between A/J, DBA/2, C57Bl/6 and 129S2 mice. A/J mice showed the highest BCG-mediated protection and lowest ML ratio, while 129S2 mice showed the lowest protection and higher ML ratio. We also found that A/J mice had a lower antigen specific IFNγ response than 129S2 mice. BCG tissue distribution appeared higher in A/J mice, although this was not statistically significant. Conclusions: These results suggest that the ML ratio has an impact on BCG-mediated protection in mice, in alignment with observations from clinical studies. A/J and 129S2 mice may therefore be useful models of BCG vaccine variability for early TB vaccine testing. We speculate that failure of BCG to protect from TB disease is linked to poor tissue distribution in a ML high immune environment.

High monocyte to lymphocyte ratio is associated with impaired protection after subcutaneous administration of BCG in a mouse model of tuberculosis

Background: The only available tuberculosis (TB) vaccine, Bacillus Calmette-Guérin (BCG), has variable efficacy. New vaccines are therefore urgently needed. Why BCG fails is incompletely understood, and the tools used for early assessment of new vaccine candidates do not account for BCG variability. Taking correlates of risk of TB disease observed in human studies and back-translating them into mice to create models of BCG variability should allow novel vaccine candidates to be tested early in animal models that are more representative of the human populations most at risk. Furthermore, this could help to elucidate the immunological mechanisms leading to BCG failure. We have chosen the monocyte to lymphocyte (ML) ratio as a correlate of risk of TB disease and have back-translated this into a mouse model. Methods: Four commercially available, inbred mouse strains were chosen. We investigated their baseline ML ratio by flow cytometry; extent of BCG-mediated protection from M ycobacterium tuberculosis infection by experimental challenge; vaccine-induced interferon gamma (IFNγ) response by ELISPOT assay; and tissue distribution of BCG by plating tissue homogenates. Results: The ML ratio varied significantly between A/J, DBA/2, C57Bl/6 and 129S2 mice. A/J mice showed the highest BCG-mediated protection and lowest ML ratio, while 129S2 mice showed the lowest protection and higher ML ratio. We also found that A/J mice had a lower antigen specific IFNγ response than 129S2 mice. BCG tissue distribution appeared higher in A/J mice, although this was not statistically significant. Conclusions: These results suggest that the ML ratio has an impact on BCG-mediated protection in mice, in alignment with observations from clinical studies. A/J and 129S2 mice may therefore be useful models of BCG vaccine variability for early TB vaccine testing. We speculate that failure of BCG to protect from TB disease is linked to poor tissue distribution in a ML high immune environment.