Background HLA-B27 is closely associated with ankylosing spondylitis (AS), but its high polymorphism made it necessary to identify the exact correlation between HLA-B27 subtypes and AS manifestation. Several studies have attempted to establish correlations between clinical features and HLA-B27 polymorphism, sometimes with inconsistent results.

Objectives The study is to investigate the correlation between clinical features of AS and HLA-B27 polymorphism in the Chinese population.

Methods The study included 846 unrelated AS patients and 959 unrelated healthy controls. Direct HLA-B sequencing procedure was applied to identify the HLA-B27 genotype. Clinical parameters including age, age of onset, family history, low back pain, peripheral arthritis, hip joint involvement, dactylitis, uveitis and sex ratio were compared among patients with different HLA-B27 subtypes. Statistical comparisons between groups were made using the Mann-Whitney Test, chi-squared test or Fisher’s exact test where applicable. Binary logistic regression model was adjusted for age, age of onset, dactylitis, and uveitis to evaluate their independent effects on clinical presentations.

Results Six hunderd and fifty-two (87.6%) AS patients are HLA-B27 positive, 39 (4.0%) healthy subjects are HLA-B27 positive. The main subtypes of HLA-B27 were HLA-B*2704 (88%) and HLA-B*2705 (10.1%) in the Chinese population. Compared to HLA-B*2704 patients, there was a significant increase of uveitis (16% vs 6.13%, p=0.002) and dactylitis (9.3% vs 3.8%, p=0.028) and the age of onset (23.0±8.0 vs 20.7±6.7, p=0.028) among HLA-B*2705 patients. Binary logistic regression analysis revealed that uveitis was significantly associated with HLA-B*2705 (P=0.008, OR: 2.63; 95% CI; 1.283-5.393). There was no significant difference in family history, low back pain, peripheral arthritis or hip joint involvement among different HLA-B27 subtypes.

Conclusions AS Patients with different HLA-B27 subtypes had different clinical features in the Chinese population. AS patients with HLA-B*2705 have higher risk of uveitis and dactylitis while those with HLA-B*2704 have an early age of onset.

References

1. Brewerton DA, Hart FD, Nicholls A, Caffrey M, James DC, Sturrock RD. Ankylosing spondylitis and HL-A 27. Lancet 1973; 1(7809): 904-7.

2. Wu Z, Lin ZM, Wei QJ, Gu J. Clinical features of ankylosing spondylitis may correlate with HLA-B27 polymorphism. Rheumatology International 2009; 29(4): 389-92.

3. Chavan H, Samant R, Deshpande A, Mankeshwar R. Correlation of HLA B27 subtypes with clinical features of ankylosing spondylitis. Int J Rheum Dis 2011; 14(4): 369-74.

4. Park KS, Kang SY, Lee WI. HLA-B27 subtypes in Korean patients with ankylosing spondylitis. Korean J Lab Med 2008; 28(1): 46-52.

Acknowledgements We are deeply indebted to all the members of the subjects for assistance in this research. And we thank the financial support from Natural Science Foundation of China Grant (31070806/C0802) and 5010 Subject of Sun Yat-sen University (2007023).

Disclosure of Interest None Declared