Hematologic manifestations of feline immunodeficiency virus infection

Studies were done on 53 cats with community-acquired infection with the feline immunodeficiency virus (FIV) to determine if hematologic abnormalities were comparable with those observed in patients seropositive for the human immunodeficiency virus (HIV). Nine cats were asymptomatic, 24 had clinical symptoms equivalent to AIDS-related complex (ARC), and 20 had AIDS-like disease. Hematologic abnormalities were detected in 75% (40 of 53) of FIV-seropositive cats, and multiple concurrent cytopenias were common. Anemia, lymphopenia, neutropenia, and thrombocytopenia occurred in 36%, 53%, 34%, and 8% of FIV-seropositive cats, respectively. Cytopenias were seen only in symptomatic (ARC or AIDS) cats. The occurrence of cytopenias and the distribution of clinical stages were similar in cats with concurrent feline leukemia virus (FeLV) infection and those with FIV alone, suggesting that these abnormalities were a direct consequence of FIV infection. In addition, abnormalities were noted in 72% of marrows from symptomatic cats and included hyperplasia of individual cell lineages and dysmorphic features. Our results demonstrate that the hematologic manifestations of FIV infection are strikingly similar to those reported in HIV-seropositive patients. Thus, FIV infection in cats is an excellent animal model to study the pathogenesis of blood and marrow abnormalities in AIDS, as well as to evaluate the hematologic toxicities of drug therapies.