Allergic contact dermatitis to nickel is associated with a Taq I HLA-DQA allelic restriction fragment

RFLP analysis of the HLA class II genes DRA, DQA, and DQB was performed in 33 patients with allergic contact eczema to nickel. A significant association with a Taq I HLA-DQA allelic restriction fragment was found. Twenty-two of 33 patients compared to 31 of 100 healthy controls had a 4.5-kb DQA fragment (corrected P value less than 0.05, relative risk 4.5, and etiologic fraction 0.52). In order to study whether the magnitude of the response in a lymphocyte proliferative assay to nickel sulfate was controlled by HLA class II genes or not, the patients were divided into low, intermediate, and high responders. No significant differences were found in the distribution of Taq I HLA class II allelic patterns between the groups.