HLA-B27 Subtypes in Korean Patients with Ankylosing Spondylitis / 대한진단검사의학회지

BACKGROUND: HLA-B27 is strongly associated with ankylosing spondylitis (AS), and its subtypes differ in their ethnic distribution. Studies worldwide have shown that B*2701, B*2702, B*2704, B*2705, B*2707, B*2708, B*2714, B*2715, and B*2719 are AS-predisposing subtypes, whereas B*2706 and B*2709 are reported to be negatively associated with AS. The aim of this study was to investigate HLA-B27 polymorphism and clinical features according to subtypes in Korean patients with AS. METHODS: Two hundred thirty samples from patients with impression of AS were analyzed by polymerase chain reaction using a sequence-specific primers (PCR-SSP) method. Pel-Freez SSP Unitray HLA-B*27 kit (Dynal Biotech, USA) including 16 primers was used to define HLA-B27 subtypes from B*2701 to B*2735. RESULTS: Among 230 samples from patients with impression of AS, 171 were HLA-B27 positive, and among 160 patients diagnosed as AS, 154 (96.3%) were HLA-B27 positive, while 17 patients not diagnosed as AS were HLA-B27 positive. Among 154 HLA-B27 positive patients with AS, 142 (92.2%) were typed as B*2705 and 9 (5.8%) were typed as B*2704. Three cases (1.9%) could be interpreted only variously because of their HLA-B27 homogeneous alleles. Between B*2705 and B*2704, no specific HLA-B27 subtype appeared to contribute to AS susceptibility (P=0.60). Difference in clinical features between B*2705 and B*2704 could not be found in this study (P>0.05). CONCLUSIONS: This study verified that HLA-B27 (96.3%) is strongly associated with AS and identified that the major subtypes of HLA-B27 positive patients with AS in Korea are B*2705 (92.2%) and B*2704 (5.8%).

HLA-B27 Subtypes in Korean Patients with Ankylosing Spondylitis: by polymerase chain reaction-sequence specific primers (PCR-SSP) method / 대한임상병리학회지

BACKGROUND: The class I major histocompatibility complex (MHC) antigen, HLA-B27 appears to be the major genetic susceptibility factor for ankylosing spondylitis (AS), anterior uveitis, and reactive arthritis, but the mechanism underlying the association remains unknown. HLA-B27 consists of eleven closely related alleles (B*2701-B*2711) which differ in a restricted number of nucleotide substitutions. The aim of this study was to investigate the frequency and the contribution of the HLA-B27 subtypes to AS. METHODS: Forty-six patients (36 AS, 4 anterior uveitis, and 2 psoriatic arthritis, 2 reactive arthritis, 1 erythema nodosum, 1 rheumatic valvular disease) were analysed. The polymerase chain reaction with sequence-specific primers (PCR-SSP) method was used to define B27 allele subtypes. The primers were specifically designed for the discrimination of HLA-B*2701-B*2711. RESULTS: Thirty-two out of forty-six patients were typed. Among them, 27 AS patients were typed. Only two subtypes were identified : 88.9% (24 out of 27) were typed as B*2705 and 11.1% (3 out of 27) were typed as B*2704. Other 5 non-AS patients ( 4 anterior uveitis & 1 psoriatic arthritis) were also typed as B*2705. CONCLUSIONS: No difference in the distribution of HLA-B27 subtypes between patients and healthy controls could be found (Fisher's exact test : P= 0.867, P>0.05). Any specific B27 subtypes don't appear to contribute to AS susceptibility.