The association of HLA B*15:02 allele and Stevens-Johnson syndrome/toxic epidermal necrolysis induced by aromatic anticonvulsant drugs in a South Indian population.

BACKGROUND: The presence of HLA-B*15:02 allele is considered a risk factor for development of Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) in patients taking aromatic anticonvulsant drugs like carbamazepine and phenytoin. The genetic association is ethnicity specific. Testing for HLA-B*15:02 allele is suggested as a prerequisite before starting carbamazepine in certain ethnic groups. There are only a few/no studies from south India on HLA association of SJS/TEN. AIMS: To identify any association between HLA-B*15:02 allele and SJS/TEN induced by carbamazepine/phenytoin among native population. METHODS (INCLUDING SETTINGS, DESIGN, AND STATISTICAL ANALYSIS USED): A case-control study done in a tertiary care center at Kottayam in Kerala state of south India. Cases were 12 native patients who developed SJS/TEN owing to aromatic anticonvulsant drugs (phenytoin - 8; carbamazepine - 4), and controls were 11 persons tolerant to these drugs from unrelated families of the same ethnic group. HLA-B typing was done by PCR SSP method. RESULTS: There was only one HLA-B*15:02 carrier among cases and controls. He/she had SJS/TEN induced by carbamazepine. CONCLUSIONS: Association of HLA-B*15:02 with phenytoin-induced SJS/TEN is rare in the population studied. The one limitation of the study was the small sample size.