Cytokines in Human Leptospirosis

Background: Leptospirosis is a zoonotic disease with increased public health concern. Cytokines produced in response to the infection with pathogenic leptospires have been proposed to be involved in the pathogenesis of the disease. The aim of the study was to measure and evaluate the levels of 27 cytokines in patients with acute leptospirosis.

Methods: The levels of 27 cytokines were measured from 42 acute leptospirosis cases; 47 samples were obtained from severe cases. Statistical analysis was performed using SPSS.

Results: IL-6, IL-8, GM-CSF, IP-10, MCP-1, and VEGF levels differed significantly between the severe cases and the control group, while GM-CSF levels differed significantly between the mild cases and the control group (p<0.05). IL-6, IP-10 and MCP-1 were elevated in most cases. IP-10 was significantly higher in severe than in non-severe cases (p<0.05). The high IP-10 levels suggest a cellular immune response, despite the fact that leptospires are not intracellular organisms. IL-1ra, MCP-1, MIP-1b and TNF-α peaked 1-5 days post onset of illness (p.o.i.), IL-1b, IL-6, IL-8, IL-9, GM-CSF, IP-10 and MIP-1a peaked 6-10 days p.o.i., while VEGF peaked later (11-15 days p.o.i.). TNF-α was significantly lower in the severe cases with pulmonary involvement (p<0.05).

Conclusions: Having a better insight into the host immune response in leptospirosis could be the basis for immunotherapeutic targets, especially for the severe cases in which antibiotic treatment is not enough.