rK39: A Cloned Antigen of Leishmania chagasi that Predicts Active Visceral Leishmaniasis

Abstract

The diagnosis of visceralleishmaniasis (VL), a serious and often fatal parasitic disease caused by members of the Leishmania donovani complex, remains problematic. Current methods rely on clinical criteria, parasite identification in aspirate material, and serology. The latter methods use crude antigen preparations lacking in specificity. A previously described cloned antigen, rK39, of Leishmania specific for all membersofthe L. donovani complex(L. chagasi,L. donovani, L. infantum) was very useful in the serodiagnosis by ELISA of both human and canine VL. The present study demonstrated that rK39 seroreactivity correlated with active disease. The sera from early or selfhealing infected subjects reacted with leishmaniallysate and were generallynonreactive with rK39. These data demonstrate the utility of rK39 in the serodiagnosis of VLand as an indicator of active disease.