Impact of tumour necrosis factor-a polymorphisms on irritant contact dermatitis

Background. Genetic variations in genes coding for cytokines involved in skin inflammation may alter their expression, thus changing the susceptibility to irritant contact dermatitis (ICD). Objectives. To determine the prevalence of polymorphisms in the cytokine genes TNFA-238 and TNFA-308 in patients with occupational ICD, and to compare it with that in controls. Methods. In a case-control study, 478 patients with occupational ICD of the hands were genotyped for TNFA-238 and TNFA-308 polymorphisms. The results were compared with those for 393 apprentices from the same high-risk occupations (controls). Results. For a carrier of a variant TNFA-238A allele, the odds ratio (OR) of acquiring ICD was 0.57 [95% confidence interval (CI) 0.34-0.97], suggesting a protective effect of the A allele. The genotype distributions were 94.4% wild type (G/G), 5.6% heterozygous (G/A) and 0% homozygous for variant allele (A/A) in patients, and 90.9%, 8.5%, and 0.6%, respectively in controls. In contrast, carriers of the variant TNFA-308A allele had an increased risk of ICD [OR 1.33; 95% CI 1.05-1.74; G/G 66.4%, G/A 31.2%, and A/A 2.4% (patients) versus 73.5%, 24.6%, 1.9% in controls]. Conclusions. Individuals with a TNFA-238 polymorphism are less prone and those with a TNFA-308 polymorphism are more prone to develop ICD of the hands, suggesting a protective versus a detrimental effect of the A allele respectively.