Lymphocytotoxins and Pernicious Anemia

Sera from 60 patients with pernicious anemia were studied for the presence of lymphocytotoxins (LCT), blocking and binding autoantibodies to intrinsic factor, and gastric parietal cell autoantibody. LCT were found in 21 sera. Cytotoxic activity was detected at 15°C but not at 24°C and did not appear to have HL-A specificity. Autocytotoxins were present in four of eight patients tested. Blocking antibody to intrinsic factor was found in 34 sera, binding antibody in 14 sera, and parietal cell antibody in 48 sera. Sera from 14 patients contained all three types of autoantibodies, and 12 sera were void of these autoantibodies. Of the 14 sera with three types of autoantibodies, LCT were detected in ten; none of the 12 sera without autoantibodies showed cytotoxic activity. These studies suggest that LCT may reflect the degree of autoimmune derangement in pernicious anemia; alternatively, LCT may represent naturally occurring immunosuppressants.