[Lymphocyte antigens in autoimmune thrombocytopenia]

18 patients with proven autoimmune thrombocytopenic purpura (ATP) (group A) were screened for human lymphocyte antigens (HLA) and compared with 13 patients with secondary thrombocytopenic purpura (group B). An additional comparison was made with a control panel of a European population (group C). HLA-B8 was present in 12 of 18 patients (66.6%) of group A, compared with only one of 13 patients (7.6%) of group B. HLA-B12 occured in 8 of 18 patients (44.4%) of group A, compared with, again, only one of 13 patients in group B. The alleles HLA-B8/B12 were observed in 7 of 18 patients (38.8%) of group A, whereas no patient of group B exhibited such phenotypes. The differences were statistically significant (p less than 0.001 to p less than 0.03). A high incidence of the antigens HLA-B8/B12 has been noted in a family of which three members displayed serious symptoms of ATP over three generations. Thus, it is conceivable that individuals who carry the HLA-B8/B12 alleles run an increased risk of developing the disease if they are exposed to additional causal factors which finally trigger ATP.