Studies on thrombocytes in patients with rheumatoid arthritis Part 1. Platelet abnormalities in patients with rheumatoid arthritis and adjuvant arthritic rats.

The platelet count and platelet adhesiveness were examined and comparing with other parameters of inflammation in patients with rheumatoid arthritis (RA) and in adjuvant arthritic rats. The platelet count in 75 patients showed good correlation with the erythrocyte sedimentation rate (γ=0.41, p<0.01). The platelet adhesiveness of 40 RA patients tested by the glassbeads method showed a significantly increased retention rate compared with that of 16 normal controls (p 0.005). In RA patients, platelet adhesiveness was significantly greater in the strongly positive CRP group (CRP 5(+) or more) than in the weakly positive CRP group (CRP 1(+) and 2(+)) (p<0.005). In adjuvant arthritic rats, the platelet count and adhesiveness increased for 5 weeks after a one shot injection. Furthermore, good correlations were noted between the platelet count and platelet adhesiveness (γ=0.72, p<0.005), platelet count and paw size (γ=0.79, p<0.001), and platelet adhesiveness and paw size (γ=0.57, p<0.001). These data suggest that platelet count and adhesiveness would be one of the good parameters of inflammation in RA patients.