HLA DR2: a predictive marker in response to cyclosporine therapy in aplastic anemia.

The effect of immunosuppressive agents on HLA DR2-aplastic anemia (AA) has recently been investigated by different groups. In the present report, we analyzed 40 Turkish AA patients, who received immunosuppressive therapy (IST) and 12 AA's who were transplanted from HLA matched siblings. HLA DR2 frequency was 0.442 and significantly higher in AA's when compared to an unrelated healthy control group (RR: 2.93, 95% confidence interval 1.48-5.77, P = 0.001. Patients received antithymocyte or antilymphocytic globulin (AT/LG) or AT/LG plus cyclosporine-A (CsA) or CsA alone. In DR2+ and DR2- patients overall response rates were 73.3 and 30%, respectively (P = 0.03). When patients were analyzed separately, CsA administration either alone or in combination with AT/LG gave favorable results in the DR2+ group (P = 0.02). In contrast AT/LG presence alone was shown to be inadequate.