Association of HLA-B39 with HLA-B27-negative ankylosing spondylitis and pauciarticular juvenile rheumatoid arthritis in Japanese patients. Evidence for a role of the peptide-anchoring B pocket.
OBJECTIVE
To investigate the characteristics of HLA-B27 that render susceptibility to seronegative spondylarthropathies.


METHODS
Serologic HLA class I typing of Japanese patients with ankylosing spondylitis (AS), juvenile rheumatoid arthritis (JRA), and healthy controls, was performed. HLA-B39 subtypes were determined by polymerase chain reaction-sequence-specific oligohybridization.


RESULTS
HLA-B27 was present in 40 of 48 patients with AS (83%), and in only 1 of 210 healthy controls (0.5%). Three of 8 patients (37.5%) who were negative for HLA-B27 were positive for HLA-B39, which was significantly higher compared with the HLA-B27-negative controls (6.2%; P = 0.01). Significant association with HLA-B39 was also noted in the JRA patients (16.7%; P < 0.01), especially in those patients with pauciarticular-onset disease (33.3%; P < 0.01). Ten of 13 HLA-B39-positive patients had subtype B*3901 and 3 had B*3902.


CONCLUSIONS
Because HLA-B27 and HLA-B39 share Glu at position 45 and Cys at position 67, both of which constitute components of the peptide-anchoring B pocket, and because they possess similar peptide-ligand motifs, our results may support either the role of the peptides presented by class I antigens or the importance of Cys at position 67, in the development of spondylarthropathies and pauciarticular-onset JRA.
D001171:Arthritis, Juvenile / Q000097:blood / Q000453:epidemiology* / Q000276:immunology*; D001483:Base Sequence; D015235:HLA-B Antigens / Q000032:analysis*; D015796:HLA-B27 Antigen / Q000032:analysis*; D059946:HLA-B39 Antigen; D015395:Histocompatibility Antigens Class I / Q000032:analysis; D006650:Histocompatibility Testing; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008969:Molecular Sequence Data; D013167:Spondylitis, Ankylosing / Q000097:blood / Q000453:epidemiology* / Q000276:immunology*
D015235:HLA-B Antigens; D015796:HLA-B27 Antigen; D059946:HLA-B39 Antigen; D015395:Histocompatibility Antigens Class I