HLA-DR frequency in Turkish aplastic anemia patients and the impact of HLA-DR2 positivity in response rate in patients receiving immunosuppressive therapy.

Certain HLA haplotypes were found guilty for certain diseases, and aplastic anemia (AA) is reported to be one of them, especially for HLA-DR2 However, HLA-DR2 frequency in AA reached significance in only one study that contained a racially heterogeneous group. We retrospectively analyzed the results of HLA-DR typing in 26 Turkish AA patients who received either immunosuppressive therapy (IST) or HLA-matched sibling bone marrow transplantation (BMT). Nineteen were male and seven were female. Median age was 22 (range, 12 to 33). In the AA group, HLA-DR2 and -DR3 frequencies were 42.3% and 11.5%, respectively. Other HLA-DR frequencies are given in Table 1. HLA-DR2 positivity was found significantly higher in patients with AA when compared with an unrelated healthy control group ( P = .02). All the patients and the control group (n = 230) were white. The relative risk of AA in DR2+ versus DR2patients is 1.99 (with a 95% confidence interval of 1.19 to 3.32). Eighteen patients received IST and 8 received BMT. Of the 18 patients given IST, 44% (8 patients) had either a complete remission (CR) (6 patients) or partial remission (PR) (2 patients). In DR2+ and DR2patients, overall response rates were 66% (4 CR