[Mononuclear cell activation in Crohn's disease. Evaluation using serum assay of neopterin and interleukin-2 soluble receptors].

To determine the degree of mononuclear blood cell activation in Crohn's disease (CD), 65 patients were prospectively investigated (22 with mild, 26 with moderate and 17 with severe disease). Serum levels of soluble receptors for interleukin-2 (SR-IL-2) were measured by ELISA. In CD patients SR-IL-2 levels were significantly higher (m = 707 +/- 326 U/ml) than in three other groups: 70 controls (m = 258 +/- 87 U/ml, p less than 0.0001); 8 patients with acute infectious colitis (m = 405 +/- 216 U/ml, p less than 0.0001); 101 HIV seropositive subjects (m = 564 +/- 216 U/ml, p less than 0.002). There was a positive correlation between SR-IL-2 level and the Van Hees activity index (r = 0.595, p less than 0.0001). On the other hand, the numbers of activated T cells (CD 3+, HLA DR+), CD 4+, CD 8+ and NK cells did not differ according to the CD activity groups. Furthermore, CD patients treated with steroids (n = 39) did not differ from those without any medication. As a marker of monocyte activation, serum neopterin level was determined by RIA. All CD patients considered as a group, serum neopterin level was 2.89 +/- 1.44 ng/l (n less than 2.5 ng/l). Neopterin level increased with disease activity (1.97 +/- 0.92 vs 3.10 +/- 1.46 vs 3.74 +/- 1.36, p less than 0.01), and was positively correlated with SR-IL-2 (r = 0.609, p less than 0.0001). These results suggest a monocyte-macrophage activation in CD, which parallels disease activity.(ABSTRACT TRUNCATED AT 250 WORDS)