ACTIVATED T-LYMPHOCYTES AND B-LYMPHOCYTES IN PERIPHERAL-BLOOD OF PATIENTS WITH CHAGAS-DISEASE

Whole blood preparations from patients with either the indeterminate ( asymptomatic) or cardiac clinical forms of chronic Trypanosoma cruzi i nfection were analyzed by flow cytometry using double-labeling to iden tify subsets of circulating lymphocytes. Several significant differenc es were demonstrated between the blood lymphocyte profiles of chagasic patients and non-chagasic controls. Clear increase in the percentages and actual numbers of double-positive cells of the phenotype CD3(+)/H LA-DR(+), as well as decrease in the percentage of CD45RA(+)/CD4(+) an d CD45RA(+)/CD8(+) T cells, indicate greater numbers of activated T ce lls circulating in the blood of infected patients. Consistent parallel increases were seen also in the B lymphocyte subset which stained dou ble-positive for CD19/CD5. There were no significant differences in th e circulation of these chronic chagasic patients in the CD4:CD8 ratios . Also, no substantive phenotypic differences were observed in the lym phocyte populations between the two ends of the clinical spectrum (ind eterminate versus cardiac) in chronic human Chagas' disease. These obs ervations demonstrate that increased levels of activated T cells and C D5(+) a cells are present in the circulation of people with chronic Ch agas' disease. These are cell phenotypes that have been associated in other conditions with autoimmune, polyclonal, and hyperimmune response s. The specificities of these activated cells and the roles they may p lay in resistance or pathogenesis during chronic Chagas' disease need now to be determined.