Immunophenotype of Peripheral Blood Lymphocytes in Dogs with Inflammatory Bowel Disease.

Abstract

BackgroundInflammatory bowel disease (IBD) is common in dogs. Despite the known importance of intestinal lymphocytes in its pathogenesis, little is known about the role of peripheral blood lymphocytes (PBLs) in IBD.ObjectivesThe aims of this study were (1) comparison of PBLs analyzed by flow cytometry (FCM) in IBD dogs and healthy controls and (2) comparison of PBLs in IBD dogs at the time of diagnosis and in dogs in clinical remission.AnimalsWhole blood samples of 19 IBD dogs at the time of diagnosis and blood samples of 6 dogs in clinical remission were collected. Ten healthy dogs served as controls.MethodsIn this prospective observational study, PBLs were analyzed with multicolor FCM by staining with a panel of anticanine and cross‐reactive monoclonal antibodies against T‐ and B‐cell differentiation antigens, including CD45, CD3, CD4, CD8α, CD8β, TCRαβ, TCRγδ, CD79αcy, and CD21.ResultsThe IBD patients’ PBLs had significantly decreased percentages of TCRγδ+ T lymphocytes (median: healthy dogs, 3.32; IBD dogs, 0.97; P = 0.03) and CD21+ B cells (median: healthy dogs, 27.61; IBD dogs, 17.26; P = 0.04). There were no significant differences in PBLs between pretreatment and follow‐up samples.Conclusions and Clinical ImportanceThe differences between PBLs in healthy and IBD dogs analyzed by FCM indicate an imbalance of lymphocytes with different immunologic functions and emphasize the potential value of this technique in a larger cohort of dogs. The PBLs did not differ between IBD dogs before treatment and clinically well‐controlled dogs after treatment.