Correlation of HLA B27 subtypes with clinical features of ankylosing spondylitis

Aim: The aim of the present study was to identify the B*27 subtypes associated with ankylosing spondylitis (AS) in our population and correlate them with clinical features of AS. Method: Whole blood samples were collected from 81 HLA-B27 positive AS patients and 29 controls (asymptomatic healthy unrelated individuals) positive for HLA-B27. Clinical details of the patients were recorded which included history of inflammatory back pain, sacroiliitis, spine involvement, enthesitis, peripheral arthritis and uveitis. HLA-B27 subtypes were detected using commercially available techniques. Fisher's exact test was used for statistical analysis. Results: The subtypes observed in AS patients were B*2705 (67.9%, 55/81), B*2704 (28.4%, 23/81), B*2707 (2/81) and B*2702 (1/81). Subtypes in the controls were B*2705 (62.07%, 18/29), B*2707 (27.59%, 8/29) and B*2704 (10.34%, 3/29). Uveitis was observed more in B*2704-positive AS patients (34.78%, 8/23) compared to B*2705-positive AS patients (16.36%, 9/55). However, the difference was not statistically significant (P = 0.130). No major differences were found between B*2705 and B*2704 for other clinical features. Conclusion: B*2705 was the main subtype observed in both patient and control groups. Frequency of B*2704 was more in AS patients compared to controls. Occurrence of AS-associated uveitis was more often in B*2704-positive AS patients compared to B*2705-positive ones.