CD40LG and leptospirosis: Immunodiagnostics using the detection of IgM antibodies during acute illness, such as the enzyme-linked immunosorbent assay (IgM-ELISA), immunofluorescence assay (IFA), and immunochromatography (ICT) formats20,21, have been implemented for the diagnosis of infectious diseases in the tropics including leptospirosis, dengue fever, rickettsioses, and melioidosis22–24.