[Excess of HLA-A2 and HLA-A2 homozygotes in patients with aplastic and Fanconi's anemias].

In 68 idiopathic aplastic anemia patients (65 HLA genotypes), HLA-A2 is slightly increased (p corrected less than 0.03) leading to a relative risk of 2.30. A slight excess of homozygotes for HLA-A was observed (22.2 vs. 14.09%), involving mostly the A2 antigen. In the siblings the patients were more frequently homozygote A2 than by chance (p less than 0.005). The same trends are observed in Fanconi's anemia = out of 18 patients, 7 are HLA-A homozygote (of whom 4 are A2). The hypothesis of the existence of one or several recessive genes involved in hematopoiesis situated close to HLA-A is advanced.