Decreases of CD4- and CD8-positive T lymphocytes in retired chromate workers.

To investigate the effects of chromates on the human immune system, we measured total T lymphocytes and their two major subpopulations (CD4+ and CD8+ T lymphocytes) in the peripheral blood of 19 retired male workers who had been exposed to chromate at a chemical plant. The results indicated that both CD4+ and CD8+ T lymphocytes were significantly decreased, resulting in decreases in total T lymphocytes and total lymphocytes.