Elevated levels of interferon-γ, interleukin-10, and interleukin-6 during active disease in Indian kala azar

We have evaluated levels of 6 cytokines in sera of 35 patients of kala azar (KA), 29 post kala azar dermal leishmaniasis (PKDL), and 18 healthy controls using cytometric bead array technology. Results indicated significantly high levels of interferon gamma (IFN-γ), interleukin (IL)-10, and IL-6 during active KA, while tumor necrosis factor alpha (TNF-α), IL-2, and IL-4 were minimal. Serum level of cytokines in PKDL was comparable to the controls while TNF-α was significantly elevated compared to KA or control. At post-treatment stage, KA patients showed a significant decrement in the levels of IFN-γ, IL-10, and IL-6; however, IL-6 remained significantly elevated above control levels. Further, comparison of cytokine levels in children and adults revealed elevated level of IL-10 in pediatric cases. SAG unresponsive cases showed significantly elevated levels of IFN-γ in comparison with the responsive cases. The results depict that type1 response is not depressed during active KA and suggest the possibility that unresponsiveness to type1 stimuli may prevail.