Histologic evidence of resolved eosinophilic esophagitis and duodenitis after dexpramipexole treatment. (A-D) Representative photomicrographs of the proximal esophagus (A-B) and duodenum (C-D), before treatment and at week 20 on dexpramipexole. (A) Squamous mucosa with active esophagitis and increased eosinophils (up to 20 per high-power field). (C) Duodenal mucosa with focally increased numbers of eosinophils (up to 100 per high-power field) and mild duodenitis. (B,D) At week 20 (on dexpramipexole), the squamous esophageal mucosa and the duodenal specimen demonstrate absence of eosinophilic infiltrates and normalization of tissue architecture. Esophageal mucosa at original magnification ×40 (B, inset) also shows lack of eosinophilic infiltrates. Images were acquired with a Nikon Eclipse 50i microscope equipped with an Olympus DP71 camera and software. Final image preparation was performed with Adobe Photoshop CS3 extended Version 10.0.1. Original magnifications: panel A, ×20/0.2 numerical aperture (NA); panel B, ×20/0.95 NA (inset, ×40); panel C, ×40/0.45 NA; panel D, ×40/1.40 NA. All panels, hematoxylin and eosin stain.