IL34 and inflammatory bowel disease: The aims of the present study were, (i) to assess the intestinal expression of PTPRZ1 in non-IBD subjects and in patients with IBD, (ii) to assess the cellular CSF-1R and PTPRZ1 expression, and, (iii) to evaluate the cytokine- and chemokine responses following IL-34 and CSF-1 stimulation of intestinal epithelial cells, PBMCs, monocytes, and macrophages.