Abstract

The cellular immune system was studied in patients with Crohn's disease (CD), not receiving corticosteroids, or azathioprine, by means of in vitro and in vivo methods. It was found, that the in vitro lymphocyte reactivity of 54 CD patients after stimulation with a cocktail of antigens (varidase, trichophyton, candida, mumps, and PPD) was significantly depressed when compared with the response of 20 simultaneously cultured healthy controls (p less than 0-001) or a group of 54 separately cultured healthy controls, matched for age and sex (p less than 0-001). The lymphocyte response of a control group of 18 patients with malnutrition or malabsorption without any evidence of inflammatory bowel disease, was higher than the response of an equal number of CD cases, although the difference failed to reach significance. Intradermally injection of the same five antigens, as used in the antigen cocktail, showed a failure to react to any antigen in 13 out of 48 CD patients, in comparison with three of 48 matched healthy controls (p less than 0-01). In both CD patients, as well as in healthy controls a significant correlation could be demonstrated between the number of positive skin tests, the area of skin induration, and the in vitro lymphocyte responsiveness after stimulation with the antigen cocktail. In the CD group no correlation was found between in vitro responsiveness and disease activity, as defined by a score of clinical and biochemical parameters. The depressed skin reactivity and the hyporesponsiveness in the lymphocyte transformation test after stimulation by an antigen cocktail suggest that depression of the anamnestic cellular immune response is a basic feature in patients with Crohn's disease.