ABSTRACT
OBJECTIVE: In rheumatoid arthritis(RA) patients, HLA-B27 has been mainly found with the same frequency as in the normal population. An increased frequency of HLA-B27 in RA has, however, repeatedly been found in northern Sweden and in Filand. The results concerning the association of HLA-B27 to the outcome of the disease have been contradictory in RA. In RA, the presence of I-ILA-B27 has shown to be a prognostic index for cervical spine subluxation. There has been no report regarding the association between RA and HLA-B27 in the Korean population. METHODS: 188 patients with RA were randomly selected from the patients who were diagnosed at Rheumatism Center of Hanyang University iHospital from October 1994 to June 1995 to establish the frequency of HLA-B27 in RA and to investigate the possible influence and prognostic significance on clinical outcome including atlantoaxial subluxations. RESULTS: The results were as follows: 1) HLA-B27 was present in 12.2% of the RA patients studied. The relative risk(RR) and etiologic fraction(EF) of HLA-B27 were 5.99 and 0. 1019 respectively. 2) The rheumatoid factor was positive in 79.8% of the total patients, 73.9% in HLA-B27 positive patients, and 80.6% in HLA-B27 negative patients. HLA-B27 was not associated with the presence of rheumatoid factor in this study. 3) HLA-B27 was not associated with the duration of morning stiffness, Ritchie index, extraarticular manifestations, the number of swollen joints, ARA functional class, ESR, C-reactive protein, or hemoglobin. HLA-B27 was not associated with the positivity of ANA and antiperinuclear factor. 4) HLA-B27 was not associated with the positive rate of erosion and Steinbrocker class in peripheral joints. 5) Atlantoaxial subluxation was present in 13% of HLA-B27 positive patients and 17% of HLA-B27 negative patients. The involvement of atlantoaxial joint including narrowing of lateral facet joints was 26.1% in HLA-B27 positive patients and 20.6% in HLA-B27 negative patients. Subaxial subluxation was presented in only 1 case in HLA-B27 negative group of total patients. HLA-B27 was not associated with the cervical changes in RA. CONCLUSIONS: An increased freuency of HLA-B27 in RA patients was significantly found in Korea(RR=5.99, EF=0.1019). However, patients with HLA-B27 had a similiar clinical profile to patients without HLA-B27 and HLA-B27 positivity did not further contribute to the severity with respect to clinical and laboratory variables or to radiological progression in peripheral joints or cervical spine.