Association Of Severe Alopecia Areata And HLA-DRB1 Alleles In Southern Chinese Han

BackgroundAlopecia aerata (AA) is an disease that presents as well defined patches of nonscarring hair loss with no overt epidermal changes. The lifetime prevalence of alopecia areata is estimated to be 0.1-0.2% of population in USA. It represents about 2% of the total dermatology outpatients in China. It is estimated that 5-7% of alopecia areata patients are severe cases. These patients can develop into alopecia totalis (AT) and alopecia universalis (AU). Severe alopecia areata is not only affect patient's apperance, but also leading to psychological problems. Currently, it is difficult for treatments. Thus, severe alopecia areata is still a therapeutic challenge for dermotologists.The etiopathogenesis of AA is not completely understood. Alopecia areata (AA) is a follicular T cell-mediated, multigene, multifactorial and autoimmune disease. The susceptibility of AA depends on the interaction of multiple genes. Previous studies have shown that HLA-Ⅱi s closely related to AA. Among HLA-Ⅱs ubtype, DRB1 is the highest genetic polymorphism and play critical roles in immune response. Furthermore, analysis of genetic polymorphism of HLA-DRB1 has been well developed. Previous studies have shown that HLA-DRB1 is related to the severity of AA, and expressions of HLA-DRB1 are different among peoples in different races and regions. Currently, there are only limited data on association of severe AA and HLA-DRB1 alleles in Southern Chinese Han.ObjectiveThis study was to investigate the association between severe alopecia areata and HLA-DRB1 alleles in Southern Chinese Han.MethodsA total of 72 patients with severe alopecia areata and 40 patients with mild alopecia areata were recruited from the same ethnic group (Han nationality) and different parts of Southern Chinese and related laboratory tests HLA typing (HLA-DRB1) was performed by polymerase chain reaction (PCR) using sequence based typing (SBT). Their HLA typing results were compared with control population of the same ethnic group and the same area (published data). The frequency of DRB1 alleles from patients and controls were compared using chi square analysis of 2 x 2 tables and strength of associations was estimated by odd ratio (OR).ResultsThere was significant statistical between mild AA group and control group in the frequency of HLA-DRB1*03, whereas, the frequency of HLA-DRB1*03 in severe AA group show no significantly difference as compared with control group.The frequency of HLA-DRB1*04 in mild AA group was no difference, whereas, there was significantly statistical difference betwwen severe AA group and control group in the frequency of HLA-DRB1*04.The frequency of HLA-DRB1*07 decreased in severe AA, appearing a statistical difference between severe AA and control (χ2=5.033, P=0.025, OR=0.143), wheras between mild AA and control, there was no difference.The frequency of HLA-DRB1*09 decreased in severe AA, showing a considerable difference between severe AA and control group (χ2=4.114, P=0.043, OR=0.558), between mild AA and control, there was no difference.No significant association was found between HLA-DRB1*01, 05, 08, 11, 12, 13, 14, 15, 16.ConclusionThere was a relationship between severity of disease and HLA-DRB1*03, 04, 07, 09 in Southern Chiense Han alopecia areata. The frequency of HLA-DRB1*07, 09 were decreased in severe AA. Wheras, the frequency of HLA-DRB1*04 were increased in severe AA. These results suggested that HLA-DRB1*04 may be high risk genes for severe AA. HLA-DRB1*07, 09 may be protective genes for severe AA. The frequency of HLA-DRB1*03 was increased in mild alopecia areata.