Background: Alopecia areata (AA) is a polygenic immune-mediated disorder affecting the hair follicle for which an association with human leukocyte antigen HLA-DRB1*11 has been described.
Objective: Two parameters including age of onset and extent of the disease (patchy AA and AT/AU forms) were correlated with the presence or absence of HLA-DRB1*11 and its alleles in 88 severe AA patients.
Methods: Patients and healthy controls were typed for HLA-DR and -DQ by molecular method.
Results: Among AA patients, 37.5% (a proportion rising to 72% when taking patients who began their first patch before the age of 20 years) were positive for HLA-DRB1*11 compared to 21.2% healthy controls (p = 0.004, RR = 2.1). DRB1*11-positive status was associated with earlier development of the first AA patch, at the mean age of 16 years compared to 27 years (p = 0.003) in DRB1*11-negative patients. Among the DRB1*11 alleles, the presence of DRB1*1104 was associated with the earliest occurrence of AA.
Conclusion: Our data indicate that the HLA system largely through DRB1*1104 allele influences AA onset rather than extension considering patchy AA and AT/AU.