CD68 expression is markedly different in Crohnʼs disease and the colitis associated with chronic granulomatous disease

Chronic granulomatous disease (CGD) is a rare inherited immunodeficiency disorder characterized by inability of phagocytes to kill certain bacteria and fungi. Histology from colon biopsies of CGD patients have shown the presence of inflammation and granulomas, almost indistinguishable from the findings seen in Crohn's disease. We sought to determine if there were any differences in the cell types that comprise the inflammatory infiltrates in inflamed colon specimens between the 2 diseases. The objective was to determine whether the pattern of inflammatory cell composition could be used to distinguish CGD-associated colitis from Crohn's colitis.Biopsies from 6 patients with Crohn's disease, 6 patients with CGD, and 6 control patients were stained with antibodies to CD3, CD4, CD8, CD68, CD79, CD163, and Foxp3. Positively staining cells per mm(2) of lamina propria were calculated for each antibody, with the exception of CD163, in which a percent area of lamina propria stained was calculated.There was a marked difference in the average CD68+ cells per mm(2) of lamina propria between the 2 groups (Crohn's: 1104.2 cells/mm(2); CGD: 242.3 cells/mm(2), P < 0.0004) and a significant difference between the CGD group and control group (Control: 565.4 cells/mm(2), CGD: 242.3 cells/mm(2), P = 0.0072). There were no significant differences between Crohn's and CGD biopsies in the other cell types.This phenomenon provides physicians with a simple and valuable tool to identify CGD in patients with colonic inflammation.