The acute phase response in canine autoimmune hemolytic anemia

This thesis is an investigation of primary autoimmune hemolytic anemia (AIHA) in 27 dogs admitted to the Ontario Veterinary College-Veterinary Teaching Hospital (OVCVTH). The hospital specific incidence of canine AIHA over the study period (January 2006 to January 2007) was 0.75%. Seasonal variation, vaccination and administration of antiparasitic products had no apparent influence on the development of AIHA. 74% (20/27) of dogs survived the acute illness and were discharged from hospital. Thromboembolic disease was a serious and frequent complication. The acute hemolytic crisis of canine AIHA was accompanied by an acute phase response (APR) characterized by increased serum C-reactive protein (CRP) and acid glycoprotein (AAG) concentrations and decreased serum albumin concentration. With treatment, resolution of the APR, as indicated by return of mean serum CRP, AAG and albumin concentrations to within the control range, occured within 7 to 9 days. Acute phase protein (APP) concentrations at initial evaluation were not predictive of acute mortality or disease severity and did not correlate with coagulation profile results (prothrombin time, partial thromboplastin time, fibrinogen concentration). Serum APP concentrations correlated with objective markers of disease control, namely hematocrit and white blood cell count. Dogs with AIHA, having survived their acute illness and achieved disease remission, had serum APP concentrations indistinguishable from control dogs. The overall 365-day survival rate was 51.8% (14/27) while the 365-day survival rate for dogs that survived to hospital discharge was 70% (14/20). Post-hospitalization mortality and the incidence of treatment related adverse effects were highest in the 2 months following hospital discharge. No dog experienced a relapse of acute hemolytic disease, however, additional autoimmune or hemolymphatic diseases developed in 3 dogs. Side effects of glucocorticoid therapy were frequent and serious complications potentially attributable to cyclosporine therapy were noted. Monitoring patients and tapering immunosuppressive agents according to a standard protocol maintained remission in all dogs and was easy for veterinarians and owners to follow. Medications were successfully discontinued in 47% of surviving patients within 180 days and in 93% of surviving patients within 365 days of discharge from hospital.