Avaiação clínico-laboratorial de sangue, medula óssea e linfonodo de gatos assintomáticos infectados pelo vírus da leucemia felina

Abstract

The feline leukemia virus (FeLV) is the most pathogenic retrovirus for the domestic cat, related to the development of genetic abnormalities, neoplasms and immunosuppression. After infection, patients can evolve to the abortive, atypical, regressive or progressive form of the disease. Cats in the progressive form have persistent antigenaemia and are more susceptible to the development of clinical changes related to FeLV. Despite the better understanding of the pathogenesis of FeLV, there are still concerns about the laboratory abnormalities induced by the virus in patients with progressive or regressive infection. The present study aims to evaluate clinical and laboratory abnormalities in cats according to the FeLV status, determined by antigenic the test and PCR. The prevalence of FeLV in the population was 20.4% (10/49), with 40% (4/10) in the regressive form and 60% (6/10) in the progressive form of the disease. Animals considered positive for FeLV (regressive and progressive infection) had a lower mean and higher median than FeLV-negative cats for CHCM (33.29 vs. 35.96; student “t”, p = 0.00192) and MCV (35.60 vs. 31.81; MannWhitney, p = 0.0046), respectively. There was no difference in the concentration of lymphocytes in the bone marrow of cats according to the infection status. However, there was a reduction in the myeloid:erythroid ratio and an increase in the blast count, with a moderate correlation between the increase in rubriblasts and myeloblasts, in relation to the current literature, even in healthy cats, negative for FeLV. The CD4+/CD8+ lymphocyte ratio median was 2.096 for animals negative for the infection, and 2.044 for positive ones (2.237 for regressors and 1.871 for progressives), with p = 0.7438 (Kruskall-Wallis ad-hoc Dunns). From the flow cytometry, a higher concentration of monocytes in the blood was observed in cats with persistent antigeneamia for FeLV (2.48%) compared to those in the regressive form of the disease (0.69%) or negative (0.73% ), with p = 0.0204 (Ad-h