[Two-color flow cytometry analysis of lymphocyte subsets in patients with acute myocardial infarction and post-myocardial infarction syndrome].

: Serial changes in lymphocyte subsets were analyzed in 37 patients with acute myocardial infarction (AMI), in 2 patients with postmyocardial infarction syndrome (PMIS), and in healthy subjects (control group) using two-color flow cytometry to investigate cellular immunity after AMI and PMIS. Peripheral blood lymphocyte subsets were measured on admission and at weeks 2, 4, 8, and 16 after the onset of AMI. The white blood cell count was significantly higher on admission and at week 2 in the AMI group compared with the control group. The percentage of CD4-positive helper T cells was significantly higher on admission and at weeks 2 and 4 in the AMI group compared with the control group, and the percentage of CD8-positive suppressor T cells was significantly lower in the AMI group at week 2 than in the control group. The ratio of helper-to-suppressor T cells peaked 2 weeks after the AMI and then decreased gradually. There were no significant changes in the CD4/CD8 ratio, the percentage of cytotoxic T cells, or the percentage of inducer T cells, throughout the observation period. There were no significant differences in the percentage of T cells, B cells, CD4-positive T cells, CD8-positive T cells, and natural killer cells between AMI patients and control subjects. The percentage of activated CD4- and CD8-positive cells was higher in the AMI group at weeks 4 and 8 than in the control group. There was no significant correlation between changes in lymphocyte subsets and infarct size. The percentage of activated CD8-positive cells was consistently higher in the PMIS group compared with the control and AMI groups. The percentage of cytotoxic T cells in one of the PMIS patients was significantly higher than in the AMI group. There were no significant differences in the proportions of other subsets between PMIS and AMI patients. The changes in lymphocyte subsets observed in patients with AMI suggested that immunological competence was enhanced in these patients. Abnormalities in humoral immunity, such as the appearance of anticardiac antibody, have been observed in patients with PMIS. Our results suggest that PMIS is also associated with changes in cellular immunity.