SOLUBLE INTERLEUKIN-2 RECEPTORS IN ULCERATIVE-COLITIS

T-CELL activation results in the release or shedding of a soluble form (45 kDa) of the cellular (55 kDa) low-affinity interleukin-2 receptor (alpha-chain) (sIL-2R). The present study was performed to investigat e if the serum concentration of sIL-2R is a marker of disease activity in patients with ulcerative colitis (UC), a chronic inflammatory bowe l disease. Twenty-seven UC patients (about half of them in remission) and 13 healthy volunteers were studied. sIL-2R concentrations were mea sured by an enzyme-linked immunosorbent assay, and significantly eleva ted median sIL-2R values were found in clinically active UC (150 pg/ml ; range 100-420), compared to inactive UC (145 pg/ml; range 110-255), and healthy controls (110 pg/ml; range 80-165) (p < 0.01). There was n o correlation between sIL-2R concentrations and extent of the disease. Due to the overlap of serum sIL-2R concentrations between different d isease stages and controls, the general diagnostic value seems to be l imited. However, since sIL-2R release is an IL-2 dependent phenomenon, we conclude that the demonstration of increased serum sIL-2R concentr ations in UC suggests the existence of an enhanced T-cell activation i n vivo in this disease. Further longitudinal studies are required to e lucidate if repeated measurements of sIL-2R levels provide an addition al way of monitoring UC disease activity in individual patients.