Immune factors and immunoregulation in tuberculosis

Vitamin D and estrogen steroid hormones and their immunogenetic roles in Infectious respiratory (TB and COVID-19) diseases

The role of steroid hormones against infectious diseases has been extensively studied. From immunomodulatory action to direct inhibition of microorganism growth, hormones D3 (VD3) and 17β-estradiol (E2), and the genetic pathways modulated by them, are key targets for a better understanding pathogenesis of infectious respiratory diseases (IRD) such as tuberculosis (TB) and the coronavirus disease-19 (COVID-19). Currently, the world faces two major public health problems, the outbreak of COVID-19, accounting for more than 6 million so far, and TB, more than 1 million deaths per year. Both, although resulting from different pathogens, the Mtb and the SARS-CoV-2, respectively, are considered serious and epidemic. TB and COVID-19 present similar infection rates between men and women, however the number of complications and deaths resulting from the two infections is higher in men when compared to women in childbearing age, which may indicate a role of the sex hormone E2 in the context of these diseases. E2 and VD3 act upon key gene pathways as important immunomodulatory players and supporting molecules in IRDs. This review summarizes the main roles of these hormones (VD3 and E2) in modulating immune and inflammatory responses and their relationship with TB and COVID-19.

Correlations Between Inflammatory Biomarkers in Tuberculosis-Associated Obstructive Pulmonary Disease Patients With Anxiety and Depression

Introduction

Tuberculosis-associated obstructive pulmonary disease (TOPD), anxiety, and depression are significant public health problems worldwide and their prevalence is common. These diseases interfere with physical, psychosocial, and economic well-being, resulting in unemployment, prolonged hospitalization, abstinence from working, and isolation.

Subjects and methods

This is a single-center, cross-sectional cohort, observational study conducted in a tertiary care hospital over six years to understand spirometry, laboratory profiles, as well as the impact on overall health, daily life, and perceived well-being in patients with TOPD.

Result

The sample size of the study was 73 patients. A total of 43 (58.5%) patients had depression with an average St. George's Respiratory Questionnaire for chronic obstructive pulmonary disease (SGRQ-C) score of 67.5, and 16 (21.9%) patients had anxiety with an average SGRQ-C score of 78.9. In the patients who scored higher on the Hamilton Depression Rating Scale (HAM-D), there was a significant correlation between Hamilton Anxiety Rating Scale (HAM-A) and HAM-D scores, as well as C-reactive protein (CRP) levels and WBC counts. In 16 (21.9%) of the patients with moderate to severe anxiety, there was a statistically significant negative correlation between higher HAM-A scores and lower WBC counts. Anxiety, depression, CRP level, WBC count, and serum fibrinogen did not show a significant correlation with the Global Initiative for Chronic Obstructive Lung Disease (GOLD) groups-based assessment of TOPD severity. A high serum fibrinogen level did not correlate with a high HAM-D score, nor did a high CRP level correlate with a high HAM-A score.

Conclusion

Psychiatric comorbidities like depression are associated with increased inflammation in chronic diseases like TOPD, but no definitive biomarker has been identified and further studies are required to identify suitable biomarkers.

The Therapeutic Effect of Intranasal Administration of Dexamethasone in Neuroinflammation Induced by Experimental Pulmonary Tuberculosis

Tuberculosis (TB) is an important infectious disease and a public health problem. The organs most frequently affected by TB are the lungs; despite this, it has been reported that TB patients suffer from depression and anxiety, which have been attributed to social factors. In previous experimental work, we observed that the extensive pulmonary inflammation characteristic of TB with high cytokine production induces neuroinflammation, neuronal death and behavioral abnormalities in the absence of brain infection. The objective of the present work was to reduce this neuroinflammation and avoid the psycho-affective disorders showed during pulmonary TB. Glucocorticoids (GCs) are the first-line treatment for neuroinflammation; however, their systemic administration generates various side effects, mostly aggravating pulmonary TB due to immunosuppression of cellular immunity. Intranasal administration is a route that allows drugs to be released directly in the brain through the olfactory nerve, reducing their doses and side effects. In the present work, dexamethasone’s (DEX) intranasal administration was evaluated in TB BALB /c mice comparing three different doses (0.05, 0.25 and 2.5 mg/kg BW) on lung disease evolution, neuroinflammation and behavioral alterations. Low doses of dexamethasone significantly decreased neuroinflammation, improving behavioral status without aggravating lung disease.

IFN-γ +874 A>T (rs2430561) gene polymorphism and risk of pulmonary tuberculosis: a meta-analysis

INTRODUCTION

The role of interferon gamma (IFN-γ) +874 A>T (rs2430561) gene polymorphism has been evaluated in different ethnicities with pulmonary tuberculosis (PTB) infection, and inconsistent results have been reported. In this study, a meta-analysis was performed to determine the precise association between IFN-γ +874 A>T gene polymorphism and PTB susceptibility.

MATERIAL AND METHODS

A total of 21 studies comprising 4281 confirmed PTB cases and 5186 healthy controls were included in this meta-analysis by searching the PubMed (Medline), EMBASE, and Google Scholar web-databases.

RESULTS

We observed reduced risk of PTB in allelic contrast (T vs. A: p = 0.001; OR = 0.818, 95% CI: 0.723-0.926), homozygous (TT vs. AA: p = 0.017; OR = 0.715, 95% CI: 0.543-0.941), heterozygous (AT vs. AA: p = 0.002; OR = 0.782, 95% CI: 0.667-0.917), dominant (TT+AT vs. AA: p = 0.002; OR = 0.768, 95% CI: 0.652-0.906), and recessive (TT vs. AA+AT: p = 0.042; OR = 0.802, 95% CI: 0.649-0.992) genetic models. In ethnicity-wise subgroup analysis, reduced risk of PTB was found in the Caucasian population. However, we did not find an association with any of the genetic models in the Asian population.

CONCLUSIONS

In conclusion, the IFN-γ +874 A>T gene polymorphism is significantly associated with reduced risk of PTB, showing a protective effect in the overall and in the Caucasian population. However, this polymorphism is not associated with PTB risk in the Asian population.

Revisiting the tuberculosis and leprosy cross-immunity hypothesis: Expanding the dialogue between immunology and paleopathology

OBJECTIVE

Our primary objective is to re-visit the tuberculosis and leprosy cross-immunity. hypothesis through the careful integration of immunology and paleopathology.

METHODS

Using an integrated theoretical analysis that evaluates clinical literature on human innate immunological responses, paleomicrobiology, bioarchaeology, and paleopathology, we develop a multifactorial model.

RESULTS

Past populations do not represent homogeneous immunological landscapes, and therefore it is likely that leprosy in Medieval Europe did not uniformly decline due to cross-immunity.

CONCLUSIONS

We recommend that bioarchaeological reconstructions of past disease experience take into consideration models that include variation in immune function based on past environments and social contexts. This provides a unique opportunity to conduct comprehensive analyses on complex immunological processes.

SIGNIFICANCE

Extrapolating results from experimental immunology to larger populations elucidates complexities of disease cross-immunity and highlights the importance of synthesizing archaeological, social, paleopathological and biological data as a means of understanding disease in the past.

LIMITATIONS

All extrapolations from data produced from in vitro studies to past populations, using living donors, pose significant limitations where, among other factors, the full reconstruction of past environmental and social contexts can frequently be sparse or incomplete.

SUGGESTIONS FOR FUTURE RESEARCH

To reduce the limitations of integrating experimental immunology with bioarchaeological reconstructions (i.e. how to use skeletal samples to reconstruct inflammatory phenotypes), we propose that osteoimmunology, or the study of the interplay between immune cells and bone cells, should be considered a vital discipline and perhaps the foundation for the expansion of paleoimmunology.

Influence of single-nucleotide polymorphisms in the IFNG towards susceptibility to tuberculosis in a Pakistani population

Tuberculosis (TB) is a global issue as one-third of the population worldwide is considered to be infected. TB has become a critical public health problem as a result of increasing drug resistance, which poses a challenge to current control strategies. Similar to environmental factors, genetic makeup of the host equally contributes to disease onset. We performed genotypic analysis to examine the relationship between IFNG and TB onset and drug resistance in a Pakistani population comprising 689 subjects. Notable differences were observed in the IFNG polymorphism (+874T/A) between the case and control groups. The frequency of the wild-type genotype (TT) in the controls (43.2%) was significantly higher than in the cases (25.3%) (odds ratio [OR] = 0.77, p < 0.0001), while the mutant genotype frequency (AA) (38.57%) in the cases was significantly higher than in the controls (22.6%) (OR = 1.46, p < 0.0001). The heterozygous genotype frequency (TA) did not significantly differ between the control and case groups. Compared with the controls, the variant allele (A) was approximately twice as frequent in the cases. Females and older people have a higher chance of disease development. Finally, the IFNG (+874T/A) polymorphism was not associated with drug sensitivity or resistance. However, a genotypic polymorphism of IFNG (+874T/A) was significantly associated with susceptibility to TB, and the T allele conferred protection against TB. Additional studies involving larger cohorts are needed to further explore this relationship between genetics and disease vulnerability.

Ensemble Technique for Prediction of T-cell Mycobacterium tuberculosis Epitopes

Development of an effective machine-learning model for T-cell Mycobacterium tuberculosis (M. tuberculosis) epitopes is beneficial for saving biologist's time and effort for identifying epitope in a targeted antigen. Existing NetMHC 2.2, NetMHC 2.3, NetMHC 3.0 and NetMHC 4.0 estimate binding capacity of peptide. This is still a challenge for those servers to predict whether a given peptide is M. tuberculosis epitope or non-epitope. One of the servers, CTLpred, works in this category but it is limited to peptide length of 9-mers. Therefore, in this work direct method of predicting M. tuberculosis epitope or non-epitope has been proposed which also overcomes the limitations of above servers. The proposed method is able to work with variable length epitopes having size even greater than 9-mers. Identification of T-cell or B-cell epitopes in the targeted antigen is the main goal in designing epitope-based vaccine, immune-diagnostic tests and antibody production. Therefore, it is important to introduce a reliable system which may help in the diagnosis of M. tuberculosis. In the present study, computational intelligence methods are used to classify T-cell M. tuberculosis epitopes. The caret feature selection approach is used to find out the set of relevant features. The ensemble model is designed by combining three models and is used to predict M. tuberculosis epitopes of variable length (7-40-mers). The proposed ensemble model achieves 82.0% accuracy, 0.89 specificity, 0.77 sensitivity with repeated k-fold cross-validation having average accuracy of 80.61%. The proposed ensemble model has been validated and compared with NetMHC 2.3, NetMHC 4.0 servers and CTLpred T-cell prediction server.

Mycobacterium avium complex infection in pigs: A review

Mycobacterial infections in pigs are caused particularly by the Mycobacterium avium complex (MAC) and these infections lead to great economic losses mainly within the countries with high pork meat production. The importance of the MAC infections in humans is rising because of its higher prevalence and also higher mortality rates particularly in advanced countries. In addition, treatment of the MAC infections in humans tends to be complicated because of its increasing resistance to antimicrobial agents. Several studies across Europe have documented the MAC occurrence in the slaughtered pigs - not only in their lymph nodes and tonsils, which are the most frequent, but also in the diaphragmas, other organs and not least in meat. This is why we need both more specific and more sensitive methods for the MAC infection detection. Different PCR assays were established as well as advanced intravital testing by the gamma interferon release test. On the other hand, tuberculin skin test is still one of the cheapest methods of mycobacterial infections detection.

Do leprosy and tuberculosis generate a systemic inflammatory shift? Setting the ground for a new dialogue between experimental immunology and bioarchaeology

It is possible that during long lasting chronic infections such as tuberculosis (TB) and leprosy individuals who generate a stronger immune response will produce a chronic shift in the systemic levels of inflammatory proteins. Consequently, the systemic immunological shift could affect inflammatory responses against other persistent pathogens such as Porphyromonas gingivalis associated with periodontal disease (PD).

OBJECTIVE

To determine if in vitro exposure to Mycobacterium tuberculosis or M. leprae lysates impacts subsequent immune responses to P. gingivalis; and to propose a new dialogue between experimental immunology and paleopathology.

MATERIAL AND METHODS

We sequentially (2 days protocol) exposed peripheral blood mononuclear cells (PBMCs) from healthy donors to bacterial lysates either from M. tuberculosis, or M. leprae, or P. gingivalis. After collecting all supernatants, we measured the expression of immune proteins TNFα and IFNγ using an enzyme-linked immunosorbent assay.

RESULTS

Early exposure (day 1) of PBMCs to M. leprae or M. tuberculosis lysates induces an inflammatory shift detected by the increase of TNFα and IFNγ when the same cells are subsequently (day 2) exposed to oral pathogen P. gingivalis.

DISCUSSION

By extrapolating these results, we suggest that chronic infections, such as TB and leprosy, could generate a systemic immunological shift that can affect other inflammatory processes such the one present in PD. We propose that the presence and severity of PD should be explored as a proxy for inflammatory status or competence when reconstructing the health profile in past populations.

Mycobacterium tuberculosis secretory proteins downregulate T cell activation by interfering with proximal and downstream T cell signalling events

Background

Mycobacterium tuberculosis (M. tuberculosis) modulates host immune response, mainly T cell responses for its own survival leading to disease or latent infection. The molecules and mechanisms utilized to accomplish immune subversion by M. tuberculosis are not fully understood. Understanding the molecular mechanism of T cell response to M. tuberculosis is important for development of efficacious vaccine against TB.

Methods

Here, we investigated effect of M. tuberculosis antigens Ag85A and ESAT-6 on T cell signalling events in CD3/CD28 induced Peripheral blood mononuclear cells (PBMCs) of PPD+ve healthy individuals and pulmonary TB patients. We studied CD3 induced intracellular calcium mobilization in PBMCs of healthy individuals and TB patients by spectrofluorimetry, CD3 and CD28 induced activation of mitogen activated protein kinases (MAPKs) in PBMCs of healthy individuals and TB patients by western blotting and binding of transcription factors NFAT and NFκB by Electrophorectic mobility shift assay (EMSA).

Results

We observed CD3 triggered modulations in free intracellular calcium concentrations in PPD+ve healthy individuals and pulmonary TB patients after the treatment of M. tuberculosis antigens. As regards the downstream signalling events, phosphorylation of MAPKs, Extracellular signal-regulated kinase 1 and 2 (ERK1/2) and p38 was curtailed by M. tuberculosis antigens in TB patients whereas, in PPD+ve healthy individuals only ERK1/2 phosphorylation was inhibited. Besides, the terminal signalling events like binding of transcription factors NFAT and NFκB was also altered by M. tuberculosis antigens. Altogether, our results suggest that M. tuberculosis antigens, specifically ESAT-6, interfere with TCR/CD28-induced upstream as well as downstream signalling events which might be responsible for defective IL-2 production which further contributed in T-cell unresponsiveness, implicated in the progression of disease.

Conclusion

To the best of our knowledge, this is the first study to investigate effect of Ag85A and ESAT-6 on TCR- and TCR/CD28- induced upstream and downstream signalling events of T-cell activation in TB patients. This study showed the effect of secretory antigens of M. tuberculosis in the modulation of T cell signalling pathways. This inflection is accomplished by altering the proximal and distal events of signalling cascade which could be involved in T-cell dysfunctioning during the progression of the disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s12865-015-0128-6) contains supplementary material, which is available to authorized users.

Complexity and Controversies over the Cytokine Profiles of T Helper Cell Subpopulations in Tuberculosis

Tuberculosis (TB) is a contagious infectious disease caused by the TB-causing bacillus Mycobacterium tuberculosis and is considered a public health problem with enormous social impact. Disease progression is determined mainly by the balance between the microorganism and the host defense systems. Although the immune system controls the infection, this control does not necessarily lead to sterilization. Over recent decades, the patterns of CD4+ T cell responses have been studied with a goal of complete understanding of the immunological mechanisms involved in the maintenance of latent or active tuberculosis infection and of the clinical cure after treatment. Conflicting results have been suggested over the years, particularly in studies comparing experimental models and human disease. In recent years, in addition to Th1, Th2, and Th17 profiles, new standards of cellular immune responses, such as Th9, Th22, and IFN-γ-IL-10 double-producing Th cells, discussed here, have also been described. Additionally, many new roles and cellular sources have been described for IL-10, demonstrating a critical role for this cytokine as regulatory, rather than merely pathogenic cytokine, involved in the establishment of chronic latent infection, in the clinical cure after treatment and in keeping antibacillary effector mechanisms active to prevent immune-mediated damage.

Profiling B and T cell immune responses to co-infection of Mycobacterium tuberculosis and hookworm in humans

Background

Humoral and cellular immune responses play protective roles against Mycobacterium tuberculosis (MTB) infection. However, hookworm infection decreases the immune response to hookworm and bystander antigens. Currently, immune responses to co-infection of MTB and hookworm are still unknown, although co-infection has been one of the public health problems in co-endemic areas of pulmonary tuberculosis (PTB) and hookworm disease. Therefore, it is essential to evaluate B and T cell immune responses to the co-infection.

Methods

Seventeen PTB cases co-infected with hookworm, 26 PTB cases, 15 patients with hookworm infection, and 24 healthy controls without PTB or hookworm infection were enrolled in the study. Expressions of CD3, CD4, CD8, CD10, CD19, CD20, CD21, CD25, CD27, CD38, FoxP3, and PD-1 were assessed on B and T cell subsets using multicolor flow cytometry.

Results

For the B cell (CD19⁺) subsets, naïve B cells (CD10⁻CD27⁻CD21⁺CD20⁺), plasma cells (CD10⁻CD27⁺CD21⁻CD20⁻), and tissue-like memory B cells (CD10⁻CD27⁻CD21⁻CD20⁺) had higher proportions, whilst resting memory B cells (CD10⁻CD27⁺CD21⁺CD20⁺) had lower proportions in the group co-infected with MTB and hookworm as compared to other groups. Frequencies of activated memory B cells (CD10⁻CD27⁺CD21⁻CD20⁺) did not differ among the four groups. For the T cell (CD3⁺) subsets, frequencies of regulatory T cells (CD4⁺CD25⁺Foxp3⁺) and exhausted CD4⁺ and CD8⁺ T cells (CD4⁺PD-1⁺ and CD8⁺PD-1⁺) were higher, and frequencies of activated CD4⁺ and CD8⁺ T cells (CD4⁺CD38⁺ and CD8⁺CD38⁺) were lower in the co-infected group as compared to the other groups.

Conclusion

The change patterns of the cell profile of circulating lymphocytes were indentified in human co-infection of MTB and hookworm, which might indicate that the humoral and cellular immune responses are more suppressed.

Electronic supplementary material

The online version of this article (doi:10.1186/s40249-015-0046-0) contains supplementary material, which is available to authorized users.

Expression pattern of transcription factors and intracellular cytokines reveals that clinically cured tuberculosis is accompanied by an increase in Mycobacterium-specific Th1, Th2, and Th17 cells

Tuberculosis (TB) remains a major global health problem and is the second biggest cause of death by infectious disease worldwide. Here, we investigate in vitro the Th1, Th2, Th17, and Treg cytokines and transcriptional factors produced after Mycobacterium-specific antigen stimulation in patients with active pulmonary tuberculosis, clinically cured pulmonary tuberculosis, and healthy donors with a positive tuberculin skin test (TST+). Together, our data indicate that clinical cure after treatment increases the percentages of Mycobacterium-specific Th1, Th2, and Th17 cells compared with those found in active-TB and TST+ healthy donors. These results show that the host-parasite equilibrium in latent TB breaks in favor of the microorganism and that the subsequent clinical recovery posttreatment does not return the percentage levels of such cells to those observed in latent tuberculosis. Additionally, our results indicate that rather than showing an increase in the percentage of Mycobacterium-specific Tregs, active-TB patients display lower Th1 : Treg and Th17 : Treg ratios. These data, together with lower Th1 : Th2 and Th17 : Th2 ratios, may indicate a mechanism by which the breakdown of the host-parasite equilibrium leads to active-TB and changes in the repertoire of Mycobacterium-specific Th cells that are associated with clinical cure after treatment of pulmonary tuberculosis.

Diagnóstico e tratamento da tuberculose latente em pacientes com doenças inflamatórias crônicas e uso de imunobiológicos inibidores do TNF-α

OBJETIVO: Traçar o perfil clínico-epidemiológico de pacientes candidatos ao uso de fármacos anti-TNF-α diagnosticados como portadores de tuberculose latente (TBL) e avaliar os desfechos do tratamento profilático com isoniazida. MÉTODOS: Análise descritiva prospectiva seguida de um estudo analítico observacional transversal dos desfechos do tratamento profilático em um grupo de 45 candidatos ao uso de fármacos anti-TNF-α. A avaliação dos pacientes constou de anamnese, exame clínico, radiografia de tórax e teste tuberculínico (TT) por Mantoux. RESULTADOS: A idade média dos pacientes foi 45 anos, e 56,0% dos pacientes eram mulheres. Doenças reumatológicas crônicas, doenças dermatológicas crônicas e doença de Crohn estavam presentes em 46,7%, 40,0% e 13,3% dos pacientes, respectivamente. A média de enduração do TT foi 14,6 mm (variação: 5-30 mm). A maioria dos pacientes (n = 30; 66,7%) apresentou enduração > 10 mm. Dos 16 pacientes com cicatriz vacinal BCG, a média de enduração foi de 15,7 mm, sendo que 14 tiveram enduração > 10 mm. Os resultados de radiografia de tórax foram considerados normais e com alterações mínimas em 64,4% e em 35,6%, respectivamente. Apenas 1 paciente (2,2%) abandonou o tratamento com isoniazida, 41 (91,2%) completaram o tratamento, 2 (4,4%) tiveram de interromper o tratamento por hepatite medicamentosa, e 1 (2,2%) foi transferido para outro hospital. Dos que completaram o tratamento, 5 apresentaram efeitos colaterais leves. CONCLUSÕES: A determinação do perfil dos candidatos ao uso de inibidores do TNF-α é importante para o manejo do tratamento da TBL, bem como para estabelecer protocolos clínicos de uso e acompanhamento do uso desses fármacos

Cytokine gene polymorphisms across tuberculosis clinical spectrum in Pakistani patients

BACKGROUND

Pakistan ranks 7(th) globally in terms of tuberculosis (TB) disease burden (incidence 181/100000 pop./yr; prevalence of 329/pop./yr). Reports from different populations show variable associations of TB susceptibility and severity with cytokine gene polymorphisms. Tuberculosis clinical severity is multi-factorial and cytokines play a pivotal role in the modulation of disease severity. We have recently reported that the ratio of two key cytokines (IFNgamma and IL10) show significant correlation with the severity spectrum of tuberculosis. The objective of the current study was to analyze the frequency of cytokine gene polymorphisms linked to high and low responder phenotypes (IFNgamma +874 T(hi)-->A(lo) and IL10 -1082 G(lo)-->A(hi)) in tuberculosis patients.

METHODS AND FINDINGS

STUDY GROUPS WERE STRATIFIED ACCORDING TO DISEASE SITE AS WELL AS DISEASE SEVERITY: Pulmonary N = 111 (Minimal, PMN = 19; Moderate, PMD = 63; Advance, PAD = 29); Extra-pulmonary N = 67 (Disseminated DTB = 20, Localized LTB = 47) and compared with healthy controls (TBNA = 188). Genotype analyses were carried out using amplification refractory mutation system-PCR (ARMS-PCR) and stimulated whole blood (WB) culture assay was used for assessing cytokine profiles. Our results suggest that the IFNgamma +874 TT genotype and T allele was overrepresented in PMN (p = 0.01) and PMD (p = 0.02). IFNgamma +874 TT in combination with IL10 GG(lo) genotypes showed the highest association (chi(2) = 6.66, OR = 6.06, 95% CI = 1.31-28.07, p = 0.01). IFNgamma AA(lo) on the other hand in combination with IL10 GG(lo) increased the risk of PAD (OR = 5.26; p = 0.005) and DTB (OR = 3.59; p = 0.045).

CONCLUSION

These findings are consistent with the role of IL10 in reducing collateral tissue damage and the protective role of IFNgamma in limiting disease in the lung.

Cellular responses to MPT-51, GlcB and ESAT-6 among MDR-TB and active tuberculosis patients in Brazil

Multi-drug resistant pulmonary tuberculosis (MDR-TB) may result from either insufficiency of the host cellular immune response or mycobacterial mechanisms of resistance. Mycobacterium tuberculosis-specific CD8+ and CD4+ T lymphocytes from MDR-TB patients are poorly studied. The aim of this study was to evaluate CD4+IFN-gamma+, CD4+IL-10+, CD8(+)IFN-gamma+ and CD8+IL-10+ cell populations by flow cytometry in non-resistant TB and multi-drug resistant tuberculosis (MDR-TB) patients from mid-central Brazil after stimulation with MPT-51, GlcB and ESAT-6 recombinant antigens from M. tuberculosis in comparison to tuberculin skin test negative (TST) healthy individuals. Non-resistant TB patients present specific cellular responses (CD4 and CD8, both IFN-gamma and IL-10) to GlcB, MPT-51 and ESAT-6; while MDR-TB patients present only CD8+IFN-gamma+ responses to ESAT-6 and CD8+IL-10+ responses to GlcB and ESAT-6. The results show that MDR-TB patients present impaired specific CD4 IFN-gamma and IL-10 responses and increased/normal specific CD8 IFN-gamma and IL-10 responses. This suggests an important role for CD8 function in these patients.

Interferon gamma/IL10 ratio defines the disease severity in pulmonary and extra pulmonary tuberculosis

Several cytokines (IFN gamma, TNF alpha, IL10 and IL6) show an association with either disease localization or dissemination in tuberculosis. There are also reports of involvement of extra-pulmonary sites in tuberculosis with differential clinical severity. However, no comparative study of biomarkers across the disease severity spectrum is available. This was the purpose of the current study. Cytokines (IFN gamma, TNFalpha, IL10 and IL6) secreted in response to a panel of stimulants (PHA, LPS or mycobacterial antigens) in whole blood were determined in eighty-two tuberculosis patients. WHO criteria was applied for stratification of patients according to disease severity: disseminated and or severe disease (EPTB1; N=29); disease localized to lung parenchyma (PTB; N=32) and disease localized to peripheral sites without lung involvement (EPTB2; N=21). Mycobacterial antigens induced IFN gamma/IL10 ratio showed a direct relationship with disease severity ranking (median ratios: EPTB1=0.21; PTB=0.85; EPTB2=7.7) and the highest correlation (Spearman Rank; rho=0.673, p<0.000001). IFN gamma/IL10 ratio also rank ordered clinical severity as it relates to anatomic sites. IFN gamma/IL10 ratio may therefore provide a useful objective marker of disease severity in both pulmonary and extra-pulmonary tuberculosis.