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%).
Adult ; Alleles ; Female ; Gene Frequency ; Genotype ; HLA-B27 Antigen/blood/*genetics ; Humans ; Korea/epidemiology ; Male ; Polymerase Chain Reaction ; Polymorphism, Genetic ; Reagent Kits, Diagnostic ; Spondylitis, Ankylosing/*diagnosis/epidemiology

BACKGROUND: Commercial kits of PCR method are widely used in HLA-B27 typing; however, their cost is relatively high. In this study, we evaluated the utility of an in-house PCR method by comparing it with that of a commercial kit. METHODS: HLA-B27 typing was done in 188 patients by using two PCR methods, Absolute(TM) HLAB27 PCR kit (Biosewoom, Korea) and an in-house PCR method. The primers used in the in-house method were prepared by Bioneer (Korea). Both PCR tests were done by Gene Amp PCR System 9600 (Perkin-Elmer Centus Corp., USA). RESULTS: The commercial kit and in-house PCR showed 100% concordance rate with each other in HLA-B27 typing. Of 188 patients tested 72 (38.3%) were positive and 116 (61.7%) were negative by the both tests. Of 62 patients with ankylosing spondylitis, 50 were positive (80.7%). CONCLUSIONS: The in-house PCR is a reliable and cost-effective method and can replace or supplement commercial kits for HLA-B27 typing.
Adult ; Female ; HLA-B27 Antigen/blood/*genetics ; Histocompatibility Testing/*methods ; Humans ; Male ; Polymerase Chain Reaction/*methods ; Reagent Kits, Diagnostic ; Sensitivity and Specificity