Binet's Classification applied in Canine Chronic Lymphocytic Leukemia

Background: Chronic Lymphocytic Leukemia in dogs (cCLL) is characterized by the accumulation of mature lymphocytes in blood and lymphoid organs. The cCCL incidence is unknown and is commonly reported in asymptomatic older dogs. Diagnosis is based on persistent lymphocytosis, bone marrow infiltration, PCR clonality and immunophenotype analysis. Objective: The possibility of applying human Binet’s classification (subtyped in A-B-C stages) to the in cLLC has been evaluated. The type C has the worst prognosis. Staging and prognostic factors were evaluated too Methods: Thirteen cases of cCCL referred to the Veterinary Teaching Hospital “M. Modenato”, between June 2011-2016 were included. The clinical and clinico-pathological findings such as lymph node enlargement, hepatosplenomegaly, lymphocytosis, anemia and thrombocytopenia were used to apply the Binet’s human classification. Results: The cCCL incidence was 0.06% (compared to a control population of 22,527). Affected dogs were >10 years old without any significant gender predisposition. No statistical association between cCLL and breed was observed. T-cell phenotype was 65% of cases. Four dogs were assigned to stage A, five to B, and four to C of the Binet’s classification. Severity of lymphocytosis, anemia and/or thrombocytopenia and the T-cell phenotype were associated with a shorter life span. Increased serum Gamma-Glutamyl Transferase (sGGT) concentration correlated with the severity of cCCL. Conclusion: The veterinary literature classified almost all cCCL in the Binet’s stage C. We established that stages A and B could be identified.