The investigation of the prevalence of immune-mediated hemolytic anemia (IMHA) in anemic dogs referred to the Veterinary Teaching Hospital of the University of Tehran

Abstract

Immune-mediated hemolytic anemia (IMHA) is one of the most common immunohematologic disorders in dogs. It is characterized by the destruction of erythrocytes (or sometimes called bone marrow erythroid precursors) mediated by immunoglobulins (IgG, IgM), with or without complement (C3). IMHA can be classified as primary (idiopathic) or secondary (underlying diseases). In this study, the anemic dogs [packed cell volume (PCV)<30%] referred to the Veterinary Teaching Hospital of the University of Tehran during a 1-year period were evaluated to find out if they had IMHA. Immunizing a rabbit with canine immunoglobulins produced the polyvalent rabbit antidog immunoglobulin for direct Coombs’ test. Of 40 anemic cases, direct Coombs’ test results were positive in 14 cases (35%). The mean age of the dogs with IMHA was 3.7 years. The most frequent breeds were Terriers (four cases) and German shepherds (three cases). The prevalence of IMHA in female dogs was more than in males. The hematologic and biochemical findings of the test include: the mean PCV (21.4±1.4%); anisocytosis in eight dogs (61%); spherocytosis in seven dogs (54%); polychromasia in five dogs (38.5%); thrombocytopenia in seven dogs (54%); hyperbilirubinemia in eight dogs (80%) out of the ten evaluated dogs; increased activity of ALT and ALP in six (46.2%) and eight (61.5%) out of thirteen evaluated dogs, respectively. In our study, the main causes of IMHA were infectious diseases (e.g., pyometra) and drug therapy (e.g., cotrimoxazole). Four of the dogs were under 2 months olds and had IMHA supposedly due to alloantibodies, blood group antigens and factors which have induced changes in RBC antigens.