Characteristics and clinical relevance of autolymphocytotoxins in patients with aplastic anemia.

Serum of 68 patients with aplastic anemia was tested for the presence of autolymphocytotoxins (auto-LTs). Prior to specific disease treatment, 16 patients (24%) displayed antibodies cytotoxic to their own lymphocytes. These antibodies had the characteristics of cold-reactive lymphocytotoxins. Their detection in patients' sera was found unrelated to a viral or toxic cause of the disease or the patients' HLA genotype. Broadly reactive anti-HLA antibodies were less frequent in pretreatment sera containing auto-LTs, suggesting that these autoantibodies could modulate alloantibody production. However, after specific disease treatment, the alloantibody frequency was comparable in patients with or without auto-LTs. We found no significant difference in response to antilymphocyte serum or bone marrow graft outcome in the patients in relation to the presence or absence of pretreatment auto-LTs. This observation suggests that the detection of these autoantibodies in aplastic anemia has no clinical relevance.