Immunologic defects in young male patients with hepatitis-associated aplastic anemia.

Extensive immunologic studies were done in 97 patients with severe aplastic anemia between 1973 and 1979. Sixteen young male patients with hepatitis-associated aplastic anemia appeared to constitute a unique subset. Compared with most patients with aplastic anemia from other causes, these 16 patients had significant reductions in the mean values of circulating T lymphocytes, serum IgG and IgM, mitogen reactivity, and decreased cutaneous hypersensitivity. The ratio of peripheral blood helper to suppressor T lymphocytes identified by monoclonal antibodies was within normal limits in 3 patients studied with hepatitis-associated aplastic anemia. Interestingly, the ratio was low (less than 1) in 3 of 7 patients studied with aplastic anemia from other causes, although the mean for these 7 patients was normal. These data suggest that patients in this subset with hepatitis-associated severe aplastic anemia have a severe immunodeficiency. Whether this immunodeficiency is the cause or result of the hepatitis or aplastic anemia, or both, is unknown.