P-SELECTIN AS A CIRCULATING MOLECULAR MARKER IN RHEUMATOID-ARTHRITIS WITH THROMBOCYTOSIS

Objective. To compare plasma concentrations of soluble P-selectin (sP- selectin) in patients with rheumatoid arthritis (RA) and thrombocytosi s with those with RA with normal platelet counts and healthy controls, and to explore the relationship between clinical and serological meas ures of disease activity. Methods. Nineteen patients with RA with mark ed thrombocytosis, 20 with normal platelet counts, and 24 controls wer e enrolled. Ritchie articular index and morning stiffness were recorde d as clinical markers of disease activity. Blood samples were collecte d for platelet count, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and plasma sP-selectin determinations. Correlations be tween sP-selectin and clinical and serological markers of disease acti vity were noted. Results. Patients with RA and thrombocytosis compared to patients with normal platelet counts showed evidence of more activ e disease when ESR, CRP, morning stiffness, and Ritchie articular inde x were considered. The thrombocyte count in patients with RA with mark ed thrombocytosis revealed a positive correlation with CRP and Ritchie articular score. Plasma sP-selectin levels were found to be significa ntly higher in patients with RA compared to controls. sP-selectin leve ls were significantly higher in patients with RA with thrombocytosis c ompared to those with normal platelet counts, and positive correlation s were observed between plasma sP-selectin levels and Ritchie index, m orning stiffness, and thrombocyte counts in those patients. Conclusion . Elevated plasma sP-selectin levels in RA could indicate the presence of a continuous underlying inflammatory stimulus. In addition, the au gmented increase in patients with RA and thrombocytosis and its correl ation with clinical activity may imply the cytokine-adhesion molecule interaction mediates the chronic inflammation of RA.