Peripheral and intestinal T lymphocyte subsets in dogs with chronic inflammatory enteropathy

Abstract

Background: Dysregulated T lymphocyte response is thought to play a key role inchronic intestinal inflammation (CIE). Objectives: To evaluate the presence of changes in peripheral and intestinal T lym-phocyte subsets and to describe potential immune and inflammatory biomarkers indogs with CIE. Animals: Sixteen healthy dogs and 26 dogs were diagnosed with CIE. Methods: Prospective case-control study evaluating peripheral and intestinal T lym-phocytes using flow cytometry and inflammatory markers obtained from completeblood cell counts. Results: Dogs with CIE had higher peripheral activated T helper (Th) lymphocytes(87/μL [18-273] CIE, 44/μL [16-162] healthy control (HC,P=.013) and regulatory Tcells (Treg; 108/μL [2-257] CIE, 34/μL [1-114] HC,P=.004). In the intestinal epithe-lium, CIE dogs presented lower percentages of Th (4.55% [1.75-18.67] CIE, 8.77%[3.79-25.03] HC,P=.002), activated Th cells (0.16% [0.02-0.83] CIE, 0.33%[0.05-0.57] HC,P=.03) and CD4/CD8 ratio (0.08 [0.02-0.39] CIE, 0.21 [0.07-0.85]HC,P=.003). Conversely, higher percentage of activated T cytotoxic cells (20.24%[3.12-77.12] CIE, 12.32% [1.21-39.22] HC,P=.04) and interferon-gamma (IFN-γ)producing T lymphocytes (7.36% [0.63-55.83] CIE, 1.44% [0.00-10.56] HC,P=.01) within the epithelium was observed. In the lamina propria the percentage of Treglymphocytes was higher (6.02% [1.00-21.48] CIE, 3.52% [0.18-10.52] HC,P=.02). Conclusions and Clinical Importance: Systemic and intestinal immune alterationsoccur in dogs with CIE suggesting that blood IFN-γproducing T lymphocytes and the systemic immune-inflamation index (SII) could potentially serve as biomarkers for the disease.