Elevated/activated myeloid leucocytes, like the CD14(+)CD16(+) monocytes are sources of TNF-⍺, and therefore, selective depletion of these cells by granulocyte/monocyte (GM) adsorption (GMA) should promote remission or enhance drug efficacy. However, studies in ulcerative colitis (UC) reported contrasting efficacy, from an 85% to statistically insignificant level. We investigated patients’ demography in responders and non-responders.

In 120 UC patients, 61 steroid naive and 59 steroid dependent, we looked for entry clinical or endoscopic features to identify responders (or non-responders) to GMA. Patients received up to an 11 Adacolumn GMA sessions over 12 weeks. Patients were clinically and endoscopically evaluated, allowing each patient to serve as her/his own control. Immunohistochemistry on colonic biopsies was to reveal the impact of GMA on leucocyte infiltration of the mucosa.

Entry average clinical activity index (CAI) was 12.6, 10–16. An 80 of 120 patients responded (CAI≤4); 45 steroid naïve (73.8%) and 35 steroid dependent (59.3%). Over 900 biopsies were processed. Infiltrating leucocytes were overwhelmingly polymorphonuclear and macrophages around and within crypt abscesses. There was a marked reduction of infiltrating leucocytes in responders. Most non-responders had extensive colonic lesions with virtually no mucosal tissue left at the lesions.

Steroid naïve patients with short duration of UC were the best responders, while patients with deep colonic lesions and extensive loss of the mucosal tissue were non-responders.