INTESTINAL PLASMACYTOSIS IN RABBITS - A HISTOLOGIC AND ULTRASTRUCTURAL-STUDY

A retrospective study revealed intestinal plasmacytosis in 53 of 102 r abbits used in various experimental studies and as controls. The breed s affected included New Zealand white (n = 46), Dutch-belted (n = 6), and Watanabe (n = 1) rabbits. Sex predisposition was not found in any breed. The mean (+/- SD) ages were 3.1 +/- 1.4 years for New Zealand w hite rabbits, 1.3 +/- 1.1 for Dutch-belted rabbits, and 2 years for th e Watanabe rabbit. The severity increased with animal age. The inciden ce was higher (P < 0.05) in rabbits used in antibody production and ch olesterol studies. The lesions were characterized by multifocal to dif fuse infiltration of well-differentiated plasma cells in the intestina l mucosa. Electron microscopic examination revealed typical plasma cel l morphology of the infiltrating cells. Small intestine and cecum were the major sites affected. In severe cases, colon, rectum, trachea, es ophagus, mesenteric lymph node, and spleen were also involved.