Fig. 2

Representative endoscopic and histologic findings before and after vedolizumab treatment in patients who failed treatment. (a, b) Endoscopic presentation before vedolizumab therapy showing diffuse erythema, edema and mucosal ulcerations. (c, d) Endoscopic presentation from the same patients after vedolizumab therapy showing persistence of mucosal ulceration and erythema. (e) Before vedolizumab therapy, chronic active colitis with basal plasmacytosis and expansion of lamina propria by lymphohistiocytes. In the top right corner, there are focal areas of neutrophil infiltration in the crypt lumen forming cryptitis and crypt abscess. (f) After vedolizumab therapy, chronic active colitis with basal plasmacytosis and Paneth cell metaplasia. In the top right corner, there are focal areas of active colitis with focal ulceration and granulation tissue