Evaluation of medullary cytokine expression and clinical and laboratory aspects in severe human visceral leishmaniasis

Background Visceral leishmaniasis (VL) is a serious public health problem. The factors that can determine whether VL develops and progresses to severe form have not been fully identified, but a specific cellular immune response appears to play a key role. Therefore, understanding immunopathogenesis can be useful in preventing a serious clinical outcome. Materials and Methods Bone marrow samples were collected from patients with severe VL (SVL) or non-severe VL (NSVL). Cytokine levels and parasitic load were analysed by RT-qPCR. There is a statistically significant difference in the leukocyte parameter in patients with SVL and NSVL compared with the control patients (p = .006 and p = .014, respectively). Results Urea, alanine transaminase and albumin parameters had a significant difference p = .036, p = .039 and p = .017, respectively, between SVL and NSVL. Although high levels of IFN-gamma, IL-10, IL-6 and TNF-alpha were present in all groups of individuals with VL, they were not statistically associated with severity. In patients with active VL, IFN-gamma and IL-10 were associated, respectively, with a reduction and increase in the parasite load, strong and significant positive association between IFN-gamma and IL-10 (rho = .627 and p = .003). Conclusion This study demonstrates that VL stimulates an non-dichotomized inflammatory response between Th1/Th2 and that bone marrow is an important tissue for immune regulation.

Automated summary

The study reveals significant differences in cytokine levels and bone marrow samples between VL patients with varying degrees of severity, with IFN-gamma and IL-10 potentially playing key roles in influencing parasitic load.