Impaired Immune Responses in Tuberculosis Patients Are Related to Weight Loss That Coexists with an Immunoendocrine Imbalance

Abstract

The study’s objective was to examine whether factors related to the host status may bear some relation with the profile of the immune response displayed by tuberculosis (TB) patients. The in vitro immune response (antigen-driven lymphoproliferation and cytokine production) and the presence of alcoholism or disease-related factors, like heart and respiratory rates, and weight loss (body mass index, BMI) were investigated in 31 males with active, untreated TB. Compared to 16 age-matched healthy males, TB patients presented depressed lymphoproliferation and increased IL-10 and TGF-β production. Multivariate analysis indicated that most differences were no longer significant when controlling for the BMI. Immune and endocrine changes coexisting with weight loss, such as circulating levels of TNF-α, IFN-γ, IL-6, cortisol, dehydroepiandrosterone and thyroid hormones, were also analyzed. While pairwise correlations between serum levels of IFN-γ, T3 or T4 and BMI were not significant, BMI was negatively correlated with IL-6 levels (p < 0.025). In turn, levels of IL-6 correlated positively with cortisol concentrations (p <0.001). Stepwise regression analysis demonstrated that BMI was only associated with IL-6 (r = –0.423, R² = 0.18), with the difference remaining significant following adjustment for the other variables. As regards IL-6, BMI, cortisol and IFN-γ could explain 74% of variability in IL-6 concentrations (R² = 0.74). No evidence for effect modification was shown when performing adjusted calculations. To conclude, the relation between weight loss and abnormal immune response of TB patients is partly associated with the immunoendocrine imbalance observed in parallel.

Intestinal Parasite Co-infection among Pulmonary Tuberculosis Cases without Human Immunodeficiency Virus Infection in a Rural County in China

“…According to the conclusions of a study that showed that weight loss was related to impaired immune responses in TB patients, 26 the finding in this study that being underweight (BMI 19) was associated with the intestinal parasitic infections only in PCs indicated that weight loss increased the risk of parasitic infection in persons with TB. The prevalence of anemia was 22-23% in this study and it was 35% in a study also conducted in rural area of central China, 27 which suggested that approximately 20-33% of the population in rural area of central China is at risk of malnutrition.…”

A Clinical Correlate of the Dysregulated Immunoendocrine Response in Human Tuberculosis

“…It constitutes a major health problem worldwide and can lead to a consumption state, characterized by a remarkable weight loss [3,4] , traditionally defined as cachexia (Greek kakos = bad and hexis = condition). Because of its chronic nature, the disease is accompanied by excessive and/or protracted cytokine production liable to affect the immunoendocrine communication [3] .…”

“…We have demonstrated that the body mass index (BMI) is negatively associated with circulating IL-6 levels in patients with active TB. Stepwise regression analysis showed that 74% of the variability in IL-6 concentration was related to BMI, cortisol and IFN-␥ serum concentrations [4] . Adjusted analysis also showed that impaired in vitro immune responses of these TB patients (reduced lymphoproliferation and increased IL-10 and TGF-␤ production) lost statistically significance when adjusted to their BMI.…”

Immunoendocrine Alterations during Human Tuberculosis as an Integrated View of Disease Pathology

“…Stepwise regression analysis demonstrated that 74% of the variability in IL-6 concentrations was related to the BMI, and cortisol and IFN-␥ serum concentrations [96] . Collectively, these results indicate that the relation between weight loss and the abnormal immune response of TB patients is partly associated with the immunoendocrine imbalance observed in parallel.…”