[Exploratory study on biomarkers associated with severe cutaneous adverse reactions]

Area of Science:

• Pharmacogenomics
• Immunodermatology
• Drug Safety

Background:

• Adverse drug reactions (ADRs) are often dose-dependent, but Type B ADRs are unpredictable and potentially life-threatening.
• Severe cutaneous adverse reactions (SCARs), including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), are delayed allergic reactions involving T-cells.
• Pharmacogenomic studies indicate strong associations between specific human leukocyte antigen (HLA) class I alleles and SCARs, varying by drug, reaction phenotype, and ethnicity.

Purpose of the Study:

• To identify genetic biomarkers, particularly HLA alleles, associated with SJS/TEN in Japanese patients.
• To investigate the prevalence of specific HLA alleles (e.g., HLA-B*1502, HLA-B*5801) in a Japanese cohort experiencing SJS/TEN.

Main Methods:

• Established a research group in 2006 comprising experts in pharmacogenomics, dermatology, ophthalmology, and psychiatry.
• Collected data from over 100 Japanese SJS/TEN patients through a nationwide case-collecting system.
• Analyzed the presence of specific HLA alleles in relation to SJS/TEN development.

Main Results:

• Collected data from over 100 Japanese SJS/TEN patients.
• Observed no carriers of HLA-B*1502, which is strongly associated with carbamazepine-induced SJS/TEN in other ethnic groups.
• Detected a moderate association between allopurinol-induced SJS/TEN and HLA-B*5801 in the Han Chinese population, but findings in the Japanese cohort require further investigation.

Conclusions:

• The genetic associations for SJS/TEN may differ significantly across ethnic groups.
• Further research is needed to elucidate the specific HLA associations for SJS/TEN in the Japanese population.
• Identifying genetic biomarkers is crucial for predicting and preventing severe, unpredictable ADRs.