Leishmaniasis in Brazil. XIV. Leishmanial and trypanosomal IgA antibody in patients with leishmaniasis and Chagas's disease.

Preserved sera from patients with various forms of leishmaniasis, acute and chronic Chagas's disease and from normal individuals were examined for the presence of IgG and IgA antibodies by the IFA test. The leishmanial antigen used in the IFA test was prepared from a hamster infected with the PH8 strain of Leishmania mexicana amazonensis; amastigotes were isolated from a skin lesion and fixed in formal phosphate-buffered saline-glucose for slide antigen. There were significantly more positive reactions with IgA conjugate in patients with mucocutaneous leishmaniasis than in those with other forms. There was no association between IgA and IgG titres. The only two sera with trypanosomal IgA antibody were from two patients with acute Chagas's disease but neither sera produced cytoplasmic or surface fluorescence of leishmanial amastigotes. The implications of the presence of leishmanial and trypanosomal IgA antibody is discussed in detail.