Lymphocyte immunophenotyping in dogs with lymphopenia of common causes.

Lymphocyte immunophenotyping can be useful for evaluating immune competence and predicting the disease prognosis. It is essential to gain knowledge about canine lymphocyte immunophenotypes in various conditions. The study deals with the characteristics of lymphopenia in dogs, with an emphasis on lymphocyte immunophenotyping by flow cytometry. Blood samples from 44 dogs with lymphopenia were included in the study. All lymphopenias sent from veterinary clinics to the diagnostic laboratory were analyzed. The hematological and biochemical abnormalities were investigated, as well as the effect of the age. Lymphopenias were classified according to the level of C-reactive protein (CRP). The percentage of T cells, B cells, Th cells and Tc cells, and T/B and Th/Tc ratios were determined by flow cytometry. Lymphopenias often occurred in dogs over 7 years of age (79.5 %). The most common were postoperative lymphopenia (31.8 %) and inflammatory diseases (29.5 %), most commonly affecting the gastrointestinal tract. Frequent abnormalities were monocytosis (56.8 %), increased CRP (72.7 %) and decreased albumin/globulin ratio (50.0 %). The percentage of Th lymphocytes was significantly lower in the group with elevated CRP than in the group with basal CRP (P = 0.0329). A negative correlation was found between the level of CRP and the percentage of Th lymphocytes (r = -0.3278, P = 0.0390). This study provided new insights into the appearance, incidence and classification of canine lymphopenia.