Inhibition of leucocyte motility and prevention of immune-complex experimental colitis by hydroxychloroquine.

The inhibitory effects of hydroxychloroquine on leucocyte motility have been compared with those of prednisolone. It has been shown to have similar potency to prednisolone as an inhibitor of human neutrophil and monocyte motility. Hydroxychloroquine has then been compared with placebo in the prevention of an immune-complex experimental colitis in rabbits. Rectal biopsies were taken from rabbits 24 hours after initiation of colitis, coded, and graded histologically. The summated gradings for acute inflammation and goblet cell depletion had worsened more in the control rabbits (mean grade +6.7) than in the treated rabbits (mean grade +1.8) P less than 0.05. There was no difference in the mononuclear cell infiltrate between the two groups. Hydroxychloroquine, which is a potent inhibitor of leucocyte motility, effectively prevents the acute inflammatory infiltrate in this experimental colitis model and therefore merits trial in human ulcerative colitis.