Functional suppressor T cell activity in Crohn's disease and the effects of sulphasalazine.

Suppressor T cell activity was measured in 18 patients with Crohn's disease and 20 controls, using two different functional assays. The effects of sulphasalazine and its metabolites on in vitro suppressor cell activity were also studied. The activity of a Con A-induced suppressor cell system in patients with Crohn's disease did not differ from that of controls, suggesting that the previously reported abnormalities are a secondary phenomenon. Furthermore, the activity of a non-induced suppressor T cell system was also normal in these patients. There was no evidence either in vivo or in vitro to suggest that sulphasalazine exerts its beneficial action by an effect on this aspect of immunoregulation.