Previous studies have demonstrated a strong association between carbamazepine-induced Stevens-Johnson syndrome and toxic epidermal necrolysis (CBZ-induced SJS/TEN) and HLA-B*1502 in Chinese, and HLA-A*3101 but not HLA-B*1502 in Caucasians and Japanese. Cases with CBZ-induced SJS/TEN negative for HLA-B*1502 were reported recently in Southeast Asia. Negative correlations between CBZ-induced SJS/TEN and B*0702 or B*4001 have also been reported, suggesting a possible protective role. Here, we genotyped HLA-B and HLA-A in 18 cases with CBZ-induced SJS/TEN, in comparison with CBZtolerant and normal controls in Southern Han Chinese. A strong association between HLA-B*1502 and CBZ-induced SJS/TEN was found, with 72.2% sensitivity and 87.1% specificity. However, we also found five patients with SJS (5/18, 27.78%) who were negative for HLA-B*1502. HLA-A*2402 was present in nine of 16 cases with SJS (56.25%, including three of five cases negative for HLA-B*1502), which was significantly more frequent than that of CBZ-tolerant controls or the general southern population. Only one case with SJS carried HLA-A*3101. No statistical difference in the mean age, sex ratio and CBZ usage was found between the CBZ-induced SJS/TEN group and the CBZ-tolerant group. In search for possible protective genetic markers in HLA-B*1502-positive but CBZ-tolerant patients, we failed to find any significant factors in the HLA alleles observed. Given the association between HLA-B*1502 and CBZ-induced SJS/TEN, genetic testing before initiating CBZ therapy is suggested in Han Chinese population. However, physicians should also be vigilant about SJS/TEN in those negative for HLA-B*1502. Other factors for the development of CBZ-induced SJS/TEN in HLA-B*1502-negative patients and protective factors in CBZ-tolerant patients should be investigated further.

Lamotrigine (LTG) is a commonly used antiepileptic drug. However, the use of LTG is limited because of its cutaneous adverse drug reactions (cADRs) ranging from mild maculopapular eruption (MPE) to severe Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). A strong association between HLA-B*1502 and carbamazepine-induced SJS ⁄ TEN has been identified in Chinese and Thai. Although three of seven cases with HLA-B*1502 have been reported in LTG-induced SJS ⁄ TEN so far, the relationship between HLA-B*1502 and LTG-induced SJS ⁄ TEN needs further investigation. It is also unclear whether there is a specific genetic marker associated with LTG-induced MPE in Chinese. In this study, we genotyped 43 Han Chinese patients treated with LTG (14 cases with LTG-induced cADRs and 29 LTG-tolerant controls), using PCR-SSP for HLA-B*1502 testing and low-resolution genotyping, as well as sequencing for four-digit genotyping. The two cases with SJS were negative for HLA-B*1502, with B1301 ⁄ 1301 and 4601 ⁄ 5610, respectively. Combining the data with previous studies, there was no significant difference in the frequency of subjects with HLA-B*1502 between the LTG-induced SJS ⁄ TEN group and the LTG-tolerant group (p = 0.08, OR 4.23, 95% CI 0.94-18.97). In the MPE group, only one was positive for HLA-B*1502. There was no significant difference in the frequency of a specific HLA-B allele between the MPE group and the LTG-tolerant group either. In this study, no significant association between HLA-B*1502 and LTG-induced SJS or MPE was found. Given the small sample size and only HLA-B locus genotyping, further large-scale studies are required to explore genetic associations with LTG-induced cADRs.

The incidence of OXC-induced cADRs was low, and no severe reactions occurred. Patients with a history of allergy are more susceptible to OXC-cADRs. No significant association between HLA-B*1502 and OXC-MPE was found. The associations between OXC-MPE and HLA alleles warrant further studies.

We found a statistical association between HLA-B*1502 and lamotrigine-induced SJS/TEN in Han Chinese subjects. Future studies with larger sample sizes are suggested to verify the results.

BackgroundWe investigated the association between oxcarbazepine (OXC)-induced maculopapular eruption (MPE) and HLA-B alleles in a northern Han Chinese population, and conducted an analysis of clinical risk factors for OXC-MPE.MethodsForty-two northern Han Chinese patients who had been treated with OXC in Changchun, China were genotyped. Among them were 14 cases with OXC-induced MPE; the remaining 28 were OXC-tolerant. The HLA-B allele frequencies of the normal control group were found in the Allele Frequency Net Database. Polymerase chain reaction-sequence specific primer( PCR-SSP )was used for HLA-B*1502 testing and direct sequencing for four-digit genotype determination.ResultsFour-digit allele sequencing showed that there was no statistically significant difference in the frequency of the HLA-B*1502 allele between the OXC-MPE and OXC-tolerant controls (3.6% versus 7.5%, OR = 0.38, 95% CI = 0.04–3.40, P = 0.65), as well as between OXC-MPE and normal controls (3.6% versus 2.4%, OR = 1.54, 95% CI = 0.20–11.73, P = 0.49). However, a significant difference in the frequency of HLA-B*3802 alleles was found between the MPE group and normal controls (10.7% versus 1.9%, OR = 6.329, 95% CI = 1.783-22.460, P = 0.018). There was no significant difference in terms of age, gender, or final OXC dose between the OXC-MPE and OXC-tolerant groups.ConclusionsThere was no significant association between OXC-MPE and HLA-B*1502 in the northern Han Chinese population in our study. Instead, HLA-B*3802 was found to be a potential risk factor for OXC-MPE.