Microbial disease and immunology Assignment Writing a scientific abstract
The clinical outcome of tuberculosis infection depends on the type of immune response to infection, which is not only responsible for protection against the disease but also for damage caused in the form of lesions. Complex interactions occur among immunocompetent cells and cytokines during the progression of pulmonary TB. The aim of this study was to investigate whether the invivo pattern of serum cytokine profile (variation in cytokine production by Th1 and Th2 T cells) is related to the clinical presentation of pulmonary TB. 29 patients (22 males and 7 females), aged between 18-69 years, were divided into three groups based on severity of pulmonary TB infection as mild (infection in single lobe, no visible cavities), moderate (two or more lobes with/without cavities), and advanced (bilateral disease, multiple cavities). 12 healthy volunteers comprised the control group. Cytokine measurements were performed using ELISA. Kruskal-Wallis, Mann-Whitney tests, and Spearmans rank test were employed for statistical analysis. Levels of the four cytokines (Th1 type cytokines – IFN-y and Il-2, and Th2 type cytokines – IL-4 and IL-10) were significant in all the three groups. however, the pattern of circulating cytokines varied. Higher levels of Th1 cell type cytokines were seen in the mild group, while high levels of both Th1 and Th2 type cytokines were seen in the moderate group. Advanced patients had higher levels of Th2 type cytokines and lower levels of Th1 type cytokines. Thus, while cell-mediated immune responses are significant in mild tuberculosis, advanced tuberculosis is characterised by impaired cell-mediated immune responses and enhanced humoral responses. It can be concluded that expansion of IL-4 and IL-10 producing T cells is positively correlated with the severity of pulmonary TB.