Rheumatology 2001; 40: 1365-1369
© 2001 British Society for Rheumatology
Original Papers |
Soluble HLA class I antigens in serum and synovial fluid from patients with rheumatoid arthritis and other arthropathies
Rheumatology and
1 Immunology Units, Hospital Universitario La Paz, Universidad Autónoma de Madrid, Madrid, Spain
Objectives. To investigate the presence of soluble HLA class I (s-HLA) antigens in serum and synovial fluid (SF) from a large cohort of rheumatic patients.
Methods. We studied clinical and analytical data and serum samples from 300 patients [122 patients with rheumatoid arthritis (RA), 38 with osteoarthritis or osteoporosis, 29 with seronegative spondyloarthropathies, 45 patients with other rheumatic diseases] and 66 healthy controls. In addition, we studied 25 paired samples of serum and SF from these groups of subjects. In RA patients, we examined whether the levels of s-HLA in serum and SF were related to the activity of the disease.
Results. The mean concentrations of s-HLA molecules in serum were slightly higher in RA patients (1.2 µg/ml) than in the other four groups (1.08, 1.01, 1.09 and 0.94 µg/ml respectively). We found no correlation between serum s-HLA levels and any variable of inflammatory disease activity in RA patients. s-HLA molecules were found in SF and at levels that correlated with those found in serum (P=0.04; r=0.4). Furthermore, s-HLA levels were higher in SF from patients with RA (1.3 µg/ml) or crystal-induced arthritis (0.98 µg/ml) than in SF from those with osteoarthritis (0.38 µg/ml) (P<0.05 and P<0.005 respectively), and these levels were correlated inversely and significantly with the score on the visual analogue scale of pain (P=0.02), the number of painful joints (P=0.05) and the level of C-reactive protein (P=0.03) in RA patients.
Conclusions. This is the first report to demonstrate the presence of s-HLA molecules in SF at levels that correlate with serum levels. The mean levels of s-HLA molecules were significantly higher in SF from patients with RA and crystal-induced arthritis than in SF from cases of osteoarthritis, and correlated inversely with certain variables of disease activity in RA patients.
KEY WORDS: s-HLA, Arthritis, Rheumatoid arthritis.
Correspondence to: S. Muñoz Fernández, Servicio de Reumatología, Hospital Universitario La Paz, Paseo de la Castellana 261, 28046 Madrid, Spain.