248 HLA-B58 Does not Increase Allopurinol Hypersensitivity among Patients with Hematologic Malignancy

BACKGROUND: HLA-B58 is a very strong marker of allopurinol-induced severe cutaneous adverse reactions (SCARs), especially in population with high frequency of HLA-B58, such as Chinese, Thai, and Korean. Although allopurinol is frequently prescribed to patients receiving chemotherapy for the prevention of tumor lysis syndrome, the risk of allopurinol-related SCARs in patients with hematologic malignancies is not evaluated. This study was conducted to find out the incidence of allopurinol-induced hypersensitivity in patients with hematologic malignancy during chemotherapy according to HLA-B58 and clinical usefulness of HLA-B58 as a risk marker for the development of allopurinol-induced hypersensitivity. METHODS: We retrospectively reviewed the medical records of patients with hematologic malignancy who ever took allopurinol and underwent serologic HLA typing for bone marrow transplantation from January 2000 to May 2010. RESULTS: Among total 463 patients, 13 (2.8%) patients experienced allopurinol hypersensitivity reactions which were simple maculopapular rash and none of those were compatible with SCARs. The mean duration of allopurinol exposure in total patients was 26.46 days (1∼2,173) and the mean duration until development of rash was 5.54 ± 1.20 days. Fifty patients (10.8%) had HLA-B58. However, the incidence of allopurinol induced rash was not different according to HLA-B58 (4% (2/50) and 2.66% (11/413) in B58 (+) and B58 (-) patients, respectively). Frequency of B58 was slightly higher in patients with rash (15.4%) compared with tolerant patients (10.7%) but the difference was statistically insignificant (P > 0.05). CONCLUSIONS: The results of this study that HLA-B58 does not increase the risk of allopurinol induced SCARs as well as simple rash among patients with hematologic malignancy. Allopurinol can be used safely in most patients with hematologic malignancy during chemotherapy and HLA typing does not give additional advantage for clinical decision.