Background: Genetic susceptibility to a variety of disease has bssn shown and it has recently been suggested that aplastic anemia is more common in adults who are HIA－
DR2＋than in the general population.
Methods: To investigate whether certain HLA-DR gene is more common in children with aplastic anemia and HLA-DR2+ gene is associated with susceptibility to cyclosporine A(CyA), we analyzed the results of HLA-DR typing in 37 children with aplastic anemia with sequence specific oligonucleotide probe(SSOP) method.
Results: Eight patients were DR2+, and there was no more common than the normal population. All of the 8 patients wlth DR2+ were DRB1*1501+ with high resolution HLA
typing. Of the 8 patients with DRB1*1501+, 3 patients were treated with CyA alone(2 patients) or CyA plus ATG(1 patient), 2 patients were treated with ATG(1 patient) or
ALG alone(1 patient). Patients treatsd with CyA only or CyA plus ATG had either a complete(1 patient) or partial(2 patients) response and patients treated ATG or ALG
alone had no response.
Conclusion: Although incidence of HLA-DR2 was not significantly higher in children with aplastic anemia then normal population, response rate to CyA was significantly
high in the DR2+ patients.

Keywords: Aplastic anemia, HLA-DR, Immunosuppresive therapy