Immune status in Crohn's disease. 2. Originally unimpaired primary cell mediated immunity in vitro.

One-way mixed lymphocyte cultures (MLC) were performed with peripheral blood lymphocytes of 21 patients with Crohn's disease (CD) not receiving salizylazosulphapyridine, steroids or azathioprine, seven patients with inflammatory bowel disease other than CD and ulcerative colitis, and 46 age- and sex-matched normal control subjects. The group of CD patients consisted of 11 patients with newly diagnosed, short-standing and so far untreated CD (group CD 1) and 10 patients previously treated with drugs and with mostly long-standing CD (group CD 2). Results showed that the MLC responsiveness was similar in all Crohn's disease groups, normal subjects and diseased controls. While there was no correlation between MLC responsiveness and either disease activity or disease duration when compared singly, those CD 2 patients who had highly active and/or very long-standing disease did exhibit a depressed MLC responsiveness as compared with that of normal subjects (p less than 0.001), CD 1 patients who had both inactive and short-standing disease (P less than 0.05), and diseased controls (0.1 greater than or equal to P greater than 0.05). The stimulatory capacity did not differ significantly between the CD groups and normal subjects or diseased controls; the latter, however, stimulated poorly compared with normal subjects (P less than 0.05). In accordance, an inverse relationship between the magnitude of the stimulatory capacity and the disease activity was found in the CD patients as a whole. These data suggest that there is no depression of the in vitro primary cell mediated immune response as a predisposing factor for CD or as an early event associated with the pathogenesis of CD.