Antibody responses in patients with cutaneous leishmaniasis of the Old World.

74 persons of Northern European origin with recent primary exposure to Leishmania tropica in Saudi Arabia were examined for their antibody responses to leishmaniae with the fluorescent antibody test (FAT), the complement fixation reaction. (CFR), and the indirect hemagglutination test (IHA). The FAT detected antibodies to L. donovani in 19 of the 41 individuals with acute lesions or scars characteristic of cutaneous leishmaniasis but in none of the 33 individuals without lesions. Our data suggest that the high proportion of persons with antibodies, as compared to other studies of cutaneous leishmaniasis of the Old World, may be the result of the relatively severe course of the disease in the majority of our patients. The CFR and the IHA did not prove to be useful for the diagnosis of this disease.