Expression of macrophage-colony stimulating factor in normal and inflammatory bowel disease intestine

Mucosal macrophages have been implicated in the pathogenesis of inflammator y bowel disease (IBD). Macrophage-colony stimulating factor (NI-CSF) influe nces monocyte/macrophage proliferation, differentiation, and activation. Se rum levels are increased in active IBD, but little is known about its role in mucosal inflammation. This study, was undertaken to determine the distri bution, frequency, and level of M-CSF expression in normal and IBD-affected intestine. RNA and tissue were studied from patients with Crohn's disease (CD) and ulcerative colitis (UC) as well as from histologically normal colo n. Tissue from intestinal tuberculosis and ischaemic colitis patients serve d as controls. M-CSF mRNA and protein were examined by semiquantitative rev erse transcriptase-polymerase chain reaction (RT-PCR), in situ hybridisatio n, and immunohistochemistry, respectively. M-CSF mRNA and protein were dete cted in histologically normal intestine, but their expression was largely c onfined to the mucosa. In active IBD, the frequency of M-CSF-expressing cel ls was significantly increased and their distribution markedly altered, alt hough no increase in mucosal M-CSF mRNA levels in intestinal tissue was obs erved. The changes were not specific to IBD, as there were similar findings in intestinal tuberculosis and ischaemic colitis. The marked alteration ob served in M-CSF expression in IBD and the importance of this cytokine in st imulating macrophage functions suggest that M-CSF may contribute to the pat hogenesis of the IBD lesion. Copyright (C) 2001 John Wiley & Sons, Ltd.