BLOOD LYMPHOCYTE SUBSET POPULATIONS IN HEALTHY BOXERS AND IN BOXERS AFFECTED BY CANINE LEISHMANIOSIS (L. INFANTUM)

Introduction: Leishmania infantum infects dogs in several Mediterranean countries, including Italy. It is known, however, that many infected dogs will not develop clinical manifestations of canine leishmaniosis (CL). Several studies have been aimed at identifying possible breed predisposition to disease and the Boxer breed, among others, has been reported to be more predisposed. The aim of the present study was to analyze peripheral blood lymphocyte subset populations in healthy boxers and in boxers affected by leishmaniosis. Materials and Methods: Nine healthy, L. infantum-negative boxers and 6 boxers with CL were studied. Infection status was determined by antibody titre and PCR. Peripheral blood mononuclear cells (PBMC) were isolated by density gradient and analyzed in flow cytometry for the expression of: CD3, CD4,CD8, CD21, CD11a/CD18, CD25 and Foxp3. Double staining was carried out for CD4/CD8 and CD4/FoxP3, while triple staining was carried out for CD4/CD25/FoxP3. Results were analyzed with the Kolmogorov-Smirnov test, with significant differences between healthy and sick dogs for each subset at p ≤ 0.05. Results: No significant differences were observed between sick dogs and healthy dogs for CD3+, CD4+CD8- or CD4+/Foxp3+ cells; levels of CD4-/CD8+ and CD4+/CD8+ lymphocytes tended to be higher in dogs with CL, even though this was not significant. The levels of CD4+/CD25+/FoxP3+ were extremely low in both groups. Conclusions: Further studies with a larger population of animals are necessary to confirm or exclude a role for lymphocyte subset variation in the development of CL in predisposed breeds.