Circulating P- and L-selectin and T-lymphocyte activation in patients withautoimmune rheumatic diseases

Circulating levels of P- and L-selectins and the degree of T-lymphocyte act ivation were assessed by enzyme-linked immunosorbent assays in 75 selected patients with rheumatoid arthritis (RA), systemic sclerosis (SSc) and syste mic lupus erythematosus (SLE) at various clinical stages, and in 40 healthy blood donors matched for age and gender. Mean levels of P-selectin were si gnificantly higher than normal in RA (lower in patients with clinical remis sion) and SSc (higher in patients with early-onset diffuse disease), but no t in SLE. In contrast, mean L-selectin levels were significantly higher tha n normal in SLE (no correlation to the degree of disease activity), but not in RA or SSc. Mean levels of soluble interleukin-2 receptors (sIL-2R), ref lecting mainly T-lymphocyte activation, in patients with active RA, SSc and SLE were almost double the normal level; however, correlations between ind ividual levels of circulating P- or L-selectins and sIL-2R within groups re vealed a strong positive correlation only between L-selectin and sIL-2R (r = 0.66, p < 0.001), and only in patients with SLE. Given the different expr ession of P- and L-selectins, these findings indicate a distinct pattern of immune cell activation in chronic diseases that share an overactivation of T-lymphocytes. The possible clinical value of quantitation of circulating P-selectin in patients with RA and SSc on the one hand, and L-selectin in p atients with SLE on the other, should be investigated by prospective studie s.