TY - JOUR T1 - Increased macrophage subset in inflammatory bowel disease: apparent recruitment from peripheral blood monocytes. JF - Gut JO - Gut SP - 669 LP - 674 DO - 10.1136/gut.35.5.669 VL - 35 IS - 5 AU - J Rugtveit AU - P Brandtzaeg AU - T S Halstensen AU - O Fausa AU - H Scott Y1 - 1994/05/01 UR - http://gut.bmj.com/content/35/5/669.abstract N2 - Mucosal specimens from active Crohn's disease (ileum, n = 6; colon, n = 6), active ulcerative colitis (n = 9), normal ileum (n = 6), and normal colon (n = 6) were subjected to paired immunofluorescence staining for characterisation of macrophage subsets in situ. In the normal state, only few CD68+ macrophages (< 10%) expressing the myelomonocytic L1 antigen (calprotectin) were seen. In inflamed mucosa, especially near small vessels, the CD68+L1+ fraction increased with the degree of inflammation, near ulcers to median 65% (range 35-91%). Cells reactive with the monoclonal antibody RFD7 were also increased in inflammation but less than 5% of them costained for L1 antigen. It is concluded that L1 producing macrophages are distinct from the RFD7+ subset and probably recently recruited from peripheral blood monocytes. Like granulocytes, L1+ macrophages may be important in non-specific defence, providing calprotectin with putative anti-microbial and anti-proliferative properties. ER -