THE CIRCULATING COMMON GAMMA-CHAIN (CD132) IN INFLAMMATORY BOWEL-DISEASE

Objective: Inflammatory bowel disease (IBD) is characterized by T cell activation. Activated T cells shed interleukin-2 receptors (IL-2R) in a soluble form. A positive correlation between sUL-2R alpha (CD25) an d disease activity is well documented in IBD, whereas IL-2R gamma (CD1 32) has not been investigated in this respect. Sera from 42 patients w ith ulcerative colitis (UC), 34 with Crohn's disease (CD), 31 healthy volunteers, and 12 patients with infectious enterocolitis were obtaine d. Methods: Disease activity was scored according to a semiquantitativ e score for UC and CD, sIL-2R alpha chain and gamma chain were assesse d by sandwich ELISA techniques using monoclonal antibodies specific fo r CD25 and CD132, respectively. Results: The concentration of IL-2R al pha chain (CD25) was found to be median 3.8 ng/ml in healthy volunteer s versus 7.0 ng/ml in UC patients (p < 0.001), and 9.6 ng/ml in CD pat ients (p < 0.001), With respect to IL-2R gamma (CD132), significantly higher amounts were found in CD patients: 6.6 ng/ml as compared with h ealthy controls <1.0 ng/ml (p < 0,004), A Kruskal-Wallis test revealed a significant correlation between alpha chain and disease activity in CD (p < 0.001), and further significantly higher gamma chain levels w ere found in active CD (p = 0,03), For UC patients, a statistically si gnificant increase of the a chain with increasing disease activity (p < 0.01) was observed, whereas no significant changes of the gamma chai n levels were found (p > 0.05), A difference of gamma chain levels wer e found between CD and UC in moderate and severe disease activity (p < 0.05), Further analyses revealed that mesalazine did not influence th e IL-2R alpha or gamma concentration either in UC or in CD patients. C onclusion: An increased circulating level of the soluble common gamma chain (CD132) seems to be found in CD, and an overlap exists between C D and UC. (C) 1998 by Am. Coll. of Gastroenterology.