Abstract
BACKGROUND: Trichloroethylene (TCE) is used extensively as an industrial solvent and has been recognized as one of the major environmental pollutants. To date, > 200 cases of TCE-induced hypersensitivity dermatitis among exposed workers have been reported worldwide, and TCE exposure has become one of the critical occupational health issues in Asia. OBJECTIVES: The study aimed to identify genetic susceptible biomarkers associated with the TCE-induced hypersensitivity dermatitis in genes located in the human leukocyte antigen (HLA) region. METHODS: From 1998 to 2006, 121 cases with TCE-induced hypersensitivity dermatitis and 142 tolerant controls were recruited into the population-based case-control study. We determined HLA alleles B, DRB1, DQA1, and DQB1, by sequence-based typing. p-Values were corrected for comparisons of multiple HLA alleles. In addition, we compared and analyzed the structure character of amino acid residues of HLA molecules found in participants. RESULTS: We obtained complete genotyping data of 113 cases and 142 controls. The allele HLA-B*1301 was present in 83 (73.5%) of 113 patients compared with 13 (9.2%) of 142 tolerant workers (odds ratio = 27.5; 95% confidence interval, 13.5-55.7; corrected p = 1.48 x 10(-21)). In addition, the HLA-B*44 alleles were present in 6.2% (7/113) of patients, but were absent in TCE-tolerant workers. Residue 95 shared by HLA-B*1301 and HLA-B*44 molecules formed a different pocket F than other residues. CONCLUSIONS: The allele HLA-B*1301 is strongly associated with TCE-induced hypersensitivity dermatitis among exposed workers and might be used as a biomarker to predict high risk individuals to TCE.