Independent Associations of the HLA-B27 Antigen and the Complement Haplotype SC21 in Chronic Anterior Uveitis.

There is evidence of an association between major histocompatibility complex (MHC) genes and acute anterior uveitis; here the authors report the frequency of class I and class III MHC phenotypes in 32 Mexican mestizo patients with chronic anterior uveitis and compared them to those present in 100 ethnically matched healthy controls. Results showed in patients statistically significant increased frequencies of HLA-B27 antigen (pC=0.02, OR=6.33, 95+ CI:1.63-26.47) and the complotype SC21 (pC=0.04, OR=4.5, 95+ CI:1.40-14.67); the authors found a decreased frequency of HLA-B35 (p=0.006, OR=0.10, 95+ CI: 0.00-0.65) as compared to normal controls. None of the individuals bearing the SC21 complotype were positive for HLA-B27, suggesting independent roles of the class I and class III antigens in the genetic susceptibility to chronic anterior uveitis.