Researching Immune Mediated Hemolytic Anemia in Dogs

Immune mediated hemolytic anemia (IMHA) is a disease of dogs where the immune system attacks and destroys red blood cells. These red blood cells deliver critical oxygen to tissues throughout the body, so after enough red blood cells are destroyed, the resulting anemia can have serious consequences. While infections, drugs, vaccines, and even cancer can trigger this immune system malfunction, in the majority of cases no specific cause is identified. These cases are called idiopathic or primary IMHA.

Idiopathic IMHA can be seen in all breeds of dogs and mixed breeds, although it seems more common in spaniel breeds and their mixes. Affected dogs can have mild, intermittent symptoms such as lethargy, weakness, and pale gums; or the anemia may be so severe that they experience an acute crisis of collapse and difficulty breathing. Treatment involves blood transfusions and supportive care during a crisis, and treatment with drugs like prednisone and others that suppress the immune system. Unfortunately, 20-70% of dogs with idiopathic IMHA do not survive. Those that do respond to treatment likely need to take immunosuppressive drugs, and deal with their side effects, long-term. Relapses can also occur.

The AKC Canine Health Foundation (CHF) and its donors are committed to funding research that can help prevent, treat and cure canine diseases such as IMHA. They have invested over $350,000 in studies exploring the underlying genetics and mechanisms of this disease, as well as improved diagnostic and treatment strategies.

Several CHF-funded studies have examined the mechanisms of IMHA, attempting to identify the specific proteins on the red blood cell surface that are targeted by the immune system and picking apart exactly which inflammatory molecules are the primary attackers involved in the abnormal immune response. Studies have also used improving genetic technologies to examine the genetic mutations and changes that may cause or occur in association with idiopathic IMHA. This includes CHF Grant 02348: Whole Blood Transcriptome Profiling of Dogs with Immune-Mediated Hemolytic Anemia (IMHA) which shows promise in identifying the genes that are turned on early in IMHA. Understanding which genes are activated and when, may help us identify dogs that are at risk for developing IMHA and pinpoint biochemical processes that we can target for treatment.

Additional CHF-funded studies have explored practical ways to improve the accuracy of diagnosing IMHA. Researchers at the University of Pennsylvania studied a new tool to identify increased clotting in dogs with IMHA. With funding from CHF Grant 02637-A: Reducing Misdiagnosis of Immune-Mediated Hemolytic Anemia, investigators are working to refine the accuracy of the commonly used slide agglutination test, which screens for the clumping of red blood cells that indicates immune-mediated destruction.

Finally, CHF-funded researchers have also studied the use of immunosuppressive drugs approved for humans in cases of canine IMHA. Additional studies to determine safe and effective dosing schedules are needed.

Idiopathic IMHA in dogs is a complex disease influenced by genetics, the immune system, the environment, and more. CHF-funded researchers are tackling this disease from all angles – developing more accurate diagnostic tests and exploring new treatment targets and medications. Thanks to the support of our donors, CHF is working to create a world where all dogs can live longer, healthier lives. Learn more about our research at akcchf.org/research.