ANTI-TRYPANOSOMA CRUZI ANTIBODY ISOTYPE PROFILES IN PATIENTS WITH DIFFERENT CLINICAL MANIFESTATIONS OF CHAGAS-DISEASE

Chagas' disease results from infection with the protozoan hemoflagella te Trypanosoma cruzi. Patients in the chronic phase of infection can b e categorized into four groups based on the presence of cardiac abnorm alities (CARD). gastrointestinal involvement (DIGEST), a combination o f both presentations (BOTH), or indeterminate (IND) if Chagas' related pathology is not apparent. Previous studies have indicated that paras ite-specific antibody production is important in both resistance to an d pathogenesis of disease. The anti-T. cruzi epimastigote stage antibo dy isotype profiles in the sera of Brazilian patients from each clinic al category, as well as from uninfected individuals (UNINF) from the s ame endemic area were analyzed. Anti-epimastigote immunoglobulin G (Ig G)1 and IgG3 levels were strikingly high with titers greater than or e qual to 1:100,000. Sera from patients in the CARD group had higher lev els of IgM than either UNINF or IND individuals, which is consistent w ith the theory that autoimmunity may contribute to chagasic cardiomyop athy. The IgA levels were higher in sera from patients with gastrointe stinal involvement when compared with individuals from any of the othe r clinical categories as well as from uninfected controls. Interesting ly, patients with both digestive and cardiac involvement did not expre ss high serum levels of IgA. However, like patients with cardiac invol vement alone, persons with both clinical manifestations produced eleva ted levels of IgG2 compared with the IND or UNINF groups. These data s uggest the presence of complex immunoregulatory processes, most likely related to differential cytokine involvement, which can influence the expression of antibody isotypes and possibly the course of disease.