IMMUNOHISTOCHEMICAL CHARACTERIZATION OF INFILTRATING CELLS IN HUMAN CHRONIC CHAGASIC MYOCARDITIS - COMPARISON WITH MYOCARDIAL REJECTION PROCESS

Cellular subpopulations that infiltrate the heart in human chronic chagasic myocarditis were defined immunohistochemically in endomyocardial biopsy (EMB) specimens. T cells formed 96.3% of the inflammatory infiltrate, predominantly CD8 + (cytotoxic/suppressor) T cells. The mean numbers of CD8 + and CD4 + (helper) T cells in the myocarditis were compared to those present in the myocardial rejection process. Mean numbers of CD8 + T cells were similar in both groups of EMB specimens while CD4+ T cell counts, CD4 +/CD8 + ratios and CD4 + antigen expression were significantly lower in the chagasic group compared to the myocardial rejection group (P < 0.002). The persistent lower number and diminished expression of CD4 + T cells suggest an immunological imbalance in patients with chronic chagasic myocarditis. A possible participation of Trypanosoma cruzi parasites in the development of such immunological abnormalities is also discussed.