Decreased proportion of CD4 T cells in the blood of atomic bomb survivors with myocardial infarction

Epidemiological studies of the atomic bomb survivors have suggested dose-re lated increases in mortality from diseases other than cancer. Cardiovascula r disease is one such noncancer disease for which increases in both mortali ty and incidence have been found to be associated with radiation dose. Immu nological studies have revealed long-term impairment of T-cell-mediated imm unity, especially involving deficiencies of CD4 helper T cells, in atomic b omb survivors. In the present study, we investigated whether decreases in C D4 T cells were associated with myocardial infarction in atomic bomb surviv ors. Of 1,006 survivors examined to determine the proportion of CD4 T cells in peripheral blood lymphocytes, 18 persons had a history of myocardial in farction, The proportion of CD4 T cells was significantly decreased with in creased radiation dose and history of myocardial infarction, Further, the p revalence of myocardial infarction was significantly greater in individuals with a lower proportion of CD4 T cells. These results suggest that myocard ial infarction in atomic bomb survivors may be associated with defects in C D4 helper T cells. (C) 1999 by Radiation Research Society.