Carbamazepine (CBZ) is the most frequent culprit drug for severe cutaneous 
adverse drug reactions (ADR), such as Stevens-Johnson syndrome (SJS), toxic 
epidermal necrolysis (TEN) and drug-induced hypersensitivity syndrome (DIHS). A 
strong association between human leukocyte antigen (HLA)-B*1502 and CBZ-induced 
SJS/TEN has been reported in Han Chinese, Thai, Malaysian and Indian 
populations, but not in Caucasian or Japanese populations. Recent studies showed 
an association between HLA-A*3101 and CBZ-induced ADR in Caucasian and Japanese 
populations. We conducted a case-control study to determine HLA genotyping of 
patients with CBZ-induced ADR in a Japanese population. Fifteen patients with 
CBZ-induced ADR and 33 subjects who had taken CBZ for more than 3 months without 
evidence of any ADR as a control were enrolled. In addition, the results of a 
CBZ-induced lymphocyte stimulation test were compared between the groups. A 
strong association was found between HLA-A31 and CBZ-induced ADR (P < 0.001), 
and a weak association was found between HLA-A11 and HLA-B51 with CBZ-induced 
ADR. No HLA-B*1502 was found in either patients or control subjects. The mean 
CBZ-induced lymphocyte stimulation index was significantly high in patients with 
CBZ-induced ADR compared with CBZ-tolerant patients (P < 0.001); however, no 
significant difference was seen between HLA-A31-positive subjects and 
HLA-A31-negative subjects in either group. These findings suggest that HLA-A31 
is strongly associated with CBZ-induced ADR in the Japanese, but does not 
determine CBZ-induced lymphocyte proliferation.