To assess the association between vitamin D deficiency and tuberculosis disease progression, we studied vitamin D levels in a cohort of tuberculosis patients and their contacts (N = 129) in Pakistan. Most (79%) persons showed deficiency. Low vitamin D levels were associated with a 5-fold increased risk for progression to tuberculosis.

Background Helicobacter pylori, a lifelong and typically asymptomatic infection of the stomach, profoundly alters gastric immune responses, and may benefit the host in protection against other pathogens. We explored the hypothesis that H. pylori contributes to the control of infection with Mycobacterium tuberculosis.Methodology/Principal FindingsWe first examined M. tuberculosis-specific IFN-γ and H. pylori antibody responses in 339 healthy Northern Californians undergoing routine tuberculin skin testing. Of 97 subjects (29%) meeting criteria for latent tuberculosis (TB) infection (LTBI), 45 (46%) were H. pylori seropositive. Subjects with LTBI who were H. pylori-seropositive had 1.5-fold higher TB antigen-induced IFN-γ responses (p = 0.04, ANOVA), and a more Th-1 like cytokine profile in peripheral blood mononuclear cells, compared to those who were H. pylori seronegative. To explore an association between H. pylori infection and clinical outcome of TB exposure, we evaluated H. pylori seroprevalence in baseline samples from two high risk TB case-contact cohorts, and from cynomolgus macaques experimentally challenged with M. tuberculosis. Compared to 513 household contacts who did not progress to active disease during a median 24 months follow-up, 120 prevalent TB cases were significantly less likely to be H. pylori infected (AOR: 0.55, 95% CI 0.0.36–0.83, p = 0.005), though seroprevalence was not significantly different from non-progressors in 37 incident TB cases (AOR: 1.35 [95% CI 0.63–2.9] p = 0.44). Cynomolgus macaques with natural H. pylori infection were significantly less likely to progress to TB 6 to 8 months after M. tuberculosis challenge (RR: 0.31 [95% CI 0.12–0.80], p = 0.04).Conclusions/Significance H. pylori infection may induce bystander effects that modify the risk of active TB in humans and non-human primates. That immunity to TB may be enhanced by exposure to other microbial agents may have important implications for vaccine development and disease control.

BackgroundPakistan ranks 7th 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 (IFNγ 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 (IFNγ +874 T hi→A lo and IL10 −1082 G lo→A hi) in tuberculosis patients.Methods and FindingsStudy 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 IFNγ +874 TT genotype and T allele was overrepresented in PMN (p = 0.01) and PMD (p = 0.02). IFNγ +874 TT in combination with IL10 GG lo genotypes showed the highest association (χ2 = 6.66, OR = 6.06, 95% CI = 1.31–28.07, p = 0.01). IFNγ 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).ConclusionThese findings are consistent with the role of IL10 in reducing collateral tissue damage and the protective role of IFNγ in limiting disease in the lung.

Background and Objective:Sepsis remains a leading cause of death across the world, carrying a mortality rate of 20–50%. Women have been reported to be less likely to suffer from sepsis and to have a lower risk of mortality from sepsis compared to men. The objective of this study was to determine the relationship between gender and mortality in sepsis, and compare cytokine profiles of male and female patients.Methods:This was a prospective case series on 97 patients admitted with sepsis. Clinical and microbiological data was gathered, blood samples were collected for cytokine (IL-10, IL-6 and TNFα) levels and patients were followed up for clinical outcome.Results:There were 54% males and 46% females, with no significant difference of age or comorbids between genders. Respiratory tract infection was the commonest source of sepsis, and was more common in females (60%) compared to males (39%) (p=0.034). Males had a higher mortality (p=0.048, RR 1.73) and plasma IL-6 level(p=0.040) compared to females. Mean IL-6 plasma level was significantly (p<0.01) higher in patients who died vs. who recovered.Conclusion:Our study shows that males with sepsis have a 70% greater mortality rate, and mortality is associated with a higher IL-6 plasma level.

Household contacts (HCs) of patients with tuberculosis (TB) are at higher risk of infection as well as the development of active disease. Longitudinal tracking of antigen-specific cytokines after acute exposure may significantly advance our understanding of the dynamic changes in cytokine patterns associated with disease establishment. To achieve this objective, we carried out a prospective cohort study with healthy HCs after exposure to TB.