Macrophage and lymphocyte subpopulations in magnifying endoscopic lesions of Crohn's disease

Using dye staining and a magnifying colonoscope, small lesions in the rectum of patients with Crohn's disease (which had otherwise appeared normal on sigmoidoscopy) can be detected. Subpopulations of macrophages and lymphocytes in the abnormal and adjacent normal areas of the rectum were studied using a panel of monoclonal antibodies. There was a distinct increase in RFD9+ and 3G8+ macrophages in the abnormal areas compared with the normal. The CD4:CD8 ratio of lymphocytes in the two areas remained unchanged.