Association of Ficolin-2 Serum Levels and FCN2 Genetic Variants with Indian Visceral Leishmaniasis

BACKGROUND Visceral leishmaniasis (VL), one of the neglected tropical diseases, is endemic in the Indian subcontinent. Ficolins are circulating serum proteins of the lectin complement system and involved in innate immunity. METHODS We have estimated ficolin-2 serum levels and analyzed the functional variants of the encoding gene FCN2 in 218 cases of VL and in 225 controls from an endemic region of India. RESULTS Elevated levels of serum ficolin-2 were observed in VL cases compared to the controls (adjusted P<0.0001). The genetic analysis revealed that the FCN2 structural variant +6359 C>T (p.T236M) was associated with VL (OR=2.2, 95% CI=1.23-7.25, P=0.008) and with high ficolin-2 serum levels. We also found that the FCN2*AAAC haplotype occurred more frequently among healthy controls when compared to cases (OR=0.59, 95%CI=0.37-0.94, P=0.023). CONCLUSIONS Our findings indicate that the FCN2 variant +6359C>T is associated with the occurrence of VL and that ficolin-2 serum levels are elevated in Leishmania infections.