# Genetic Variants Associated with Non-Steroidal Anti-Inflammatory Drug-Induced Stevens–Johnson Syndrome and Toxic Epidermal Necrolysis

## TL;DR

This study explores genetic markers linked to severe skin reactions caused by pain medications in a Thai population, focusing on HLA alleles.

## Contribution

The study identifies HLA-DQB1*03:02 as a potential genetic risk factor for NSAID-induced SJS/TEN in Thais, particularly for piroxicam-related cases.

## Key findings

- HLA-DQB1*03:02 is significantly associated with NSAID-induced SJS/TEN in Thai patients.
- HLA-B*56:01 and HLA-A*68:01 show potential associations with SJS/TEN, though not significant after Bonferroni correction.
- CYP2C9*3 polymorphism does not show a significant association with NSAID-induced SJS/TEN.

## Abstract

Background/Objectives: Non-steroidal anti-inflammatory drugs (NSAIDs) are widely prescribed to help alleviate pain and treat inflammation, but they are also recognized as common causes of severe cutaneous adverse reactions (SCARs), including Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). Despite their clinical importance, pharmacogenetic markers to predict individual susceptibility to NSAID-induced SJS/TEN remain insufficiently defined. This study investigated associations between HLA class I and II alleles, CYP2C9 polymorphisms, and NSAID-induced SJS/TEN in a Thai population. Methods: A total of 18 patients with NSAID-induced SJS/TEN and 54 NSAID-tolerant controls were enrolled. Genotype data from 183 unrelated Thai individuals without a history of drug allergy were included as a general population control group. Genotyping was performed for HLA class I and II alleles and the CYP2C9*3 variant. Results: HLA-DQB1*03:02 was significantly associated with NSAID-induced SJS/TEN (OR = 9.23, 95% CI = 2.19–38.83, p = 0.0024, Pc = 0.0312), particularly those triggered by piroxicam (OR = 13.71, 95% CI = 2.81–66.86, p = 0.0012, Pc = 0.0156). Additional associations were identified for HLA-B*56:01 and HLA-A*68:01 in the overall NSAID-induced SJS/TEN group. The subgroup analysis suggested that these alleles, along with HLA-DRB1*04:03, were associated with an increased risk of piroxicam-induced SJS/TEN. However, these associations did not remain statistically significant after Bonferroni’s correction. No significant association was identified for CYP2C9*3. Conclusions: This study identified specific HLA alleles, particularly HLA-DQB1*03:02, as candidate pharmacogenetic risk factors for NSAID-induced SJS/TEN in a Thai population, especially in piroxicam-associated cases. However, these associations should be considered exploratory. Larger, multicenter, multi-ethnic studies are required to validate these findings and clarify their potential clinical utility.