HLA class I and class II genotyping in patients with chronic urticaria

Chronic urticaria (CU) is a common disease in which pathogenesis is unclear and which is resistant to therapy. Recent investigations have indicated that autoimmunity plays a role in nearly one third of CU patients. The present study aimed to investigate the relationship between human leukocyte antigen (HLA) class I and class II antigens and immune pathogenesis of CU.

HLA class I and class II antigens were investigated in 40 patients diagnosed with CU, utilizing serologic techniques and polymerase chain reactions. The study was performed between October 2005 and May 2006. Further HLA typing in patient subsets was done depending on the response of patients to intradermal injection of autologous serum. About 30 healthy and genetically unrelated individuals formed the control group for evaluation.

The results revealed that HLA-B44 frequency was significantly higher (25%) in the patient group as compared with the matched control group (3.33%) (p = 0.033, OR = 9.667). There was no significant difference in HLA-A allelic distribution between the patient and control groups. In the genotyping of class II HLA alleles, HLA-DRB1*01 (25%) (p = 0.033, OR = 9.667) and HLA-DRB*15 (25%) (p = 0.033, OR = 9.667) were predominant alleles in the patient group.

The association of HLA-B44, HLA-DRB1*01 and HLA-DRB*15 alleles with idiopathic CU suggests that there is a genetic component in the pathogenesis of CU.