Vaccination has been incriminated as a trigger of immunemediated hemolytic anemia (IMHA) in dogs and in people, but evidence t o support this association is lacking. In a controlled retrospective study, idiopathic IMHA was identified in 58 dogs over a 27-month period. When compared with a randomly selected control group of 70 dogs (presented for reasons other than IMHA) over the same period, the distribution of cases versus time since vaccination was different ( P < .05). Fifteen of the dogs (26%) had been vaccinated within 1 month (mean, 13 days; median, 14 days; range, 1 t o 27 days) of developing IMHA ( P < .0001), whereas in the control group no marked increase in frequency of presentation was seen in the first month after vaccination. The dogs with IMHA were divided into 2 groups based on time since vaccination: the vaccine IMHA group included dogs vaccinated within 1 month of developing IMHA; the nonvaccine IMHA group included dogs that developed IMHA more than 1 month after vaccination. The recently vaccinated dogs with IMHA [vaccine IMHA group) had significantly lower platelet counts ( P < .05) and a trend towards increased prevalence Materials and MethodsDogs with IMHA were selected from medical records at the Veterinary Hospital of the University of Pennsylvania (VHUP) from December 1992 to March 1995. IMHA was diagnosed when there was anemia and evidence of hemolysis (as evidenced by hyperbilirubinemia, bilirubinuria, and/or hemoglobinuria) with a positive direct Coombs' test or persistent autoagglutination after saline washing of red blood cells (which precluded performing a Coombs' test). Dates, types, and brands of most recent vaccines were recorded. Seventy adult dogs with complete vaccination records that did not have IMHA, anemia, or other immune diseases were randomly selected throughout the same time period to act as a control group. To investigate the association between recent vaccination and IMHA, the time from last vaccination to presentation (control group) or onset of IMHA were compared for the dogs with idiopathic IMHA and the control dogs. Dogs with IMHA were then assigned to 1 of 2 groups depending on the time from last vaccination to the appearance of clinical signs of IMHA. The vaccine IMHA group included dogs that had been vaccinated within I month of developing IMHA. The nonvaccine IMHA group included dogs that had been vaccinated more that 1 month before developing IMHA. Dogs were excluded if another potential cause of IMHA such as drug or toxin exposure, infectious disease, or neoplasia was identified from clinical findings or the patient's history. Two dogs were excluded because vaccine histories were unavailable.Blood samples from all patients were evaluated for spherocytosis and microscopic autoagglutination. Autoagglutination was considered positive if it persisted through 3 washes with phosphate-buffered saline solution. The Coombs' test was performed within 24 hours of collection. EDTA-anticoagulated blood cells were washed 4 times and incubated as a 2% cell suspension a...

Cyclophosphamide is commonly used with prednisone in the initial treatment of severe idiopathic immune-mediated hemolytic anemia (IMHA) in dogs because retrospective reports suggest its benefit. This randomized controlled prospective clinicaltrial evaluated whether combined cyclophosphamide and prednisone therapy is more efficacious than prednisone therapy alone in the initial treatment of IMHA. Eighteen dogs with acute, severe idiopathic IMHA were randomly assigned to 1 of 2 treatment groups. The P group received prednisone therapy alone (1-2 mg/kg PO q12h), and the PC group received prednisone (1-2 mg/kg PO q12h) and cyclophosphamide (50 mg/m2 PO q24h for 4 consecutive days a week) for 4 weeks. The mortality rate in the P group was 20% (2 of 10), and in the PC group, the mortality rate was 38% (3 of 8). There was no difference in sequential CBC evaluations between the 2 groups. However, whereas dogs in the P group showed increases in reticulocyte count, reticulocytosis was suppressed in dogs in the PC group during the 1st week of therapy. Spherocytosis resolved more quickly in the P group (day 21) than in the PC group (day 28), but the time taken to achieve a negative Coombs' test result was comparable between groups. No difference was observed in the volume of packed red blood cells (pRBCs) given per transfusion between treatment groups, but more dogs in the PC group required a 2nd transfusion. The results of this limited study suggest that cyclophosphamide plus prednisone has no benefit over prednisone alone in the initial treatment of acute, severe idiopathic IMHA indogs.

A predicted mean corpuscular volume (PMCV) was calculated from the reticulocyte percentage and compared to the actual mean corpuscular volume for the purpose of determining bone marrow iron depletion in the dog. A difference of greater than 10 fl between the pMCV and the actual measured MCV accurately predicted the absence of stainable iron in bone marrow aspirates (sensitivity 86%, specificity 93%). The difference (Diff) between the predicted and actual measured MCV may also be a valuable method for following response to iron therapy in dogs with iron deficiency anemia without the necessity for repeated bone marrow examination. The predicted MCV may be useful in determining which patients are not at risk for canine iron deficiency.

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Cyclophosphamide is commonly used with prednisone in the initial treatment of severe idiopathic immune-mediated hemolytic anemia (IMHA) in dogs because retrospective reports suggest its benefit. This randomized controlled prospective clinical trial evaluated whether combined cyclophosphamide and prednisone therapy is more efficacious than prednisone therapy alone in the initial treatment of IMHA. Eighteen dogs with acute, severe idiopathic IMHA were randomly assigned to 1 of 2 treatment groups. The P group received prednisone therapy alone (1-2 mg/kg PO q12h), and the PC group received prednisone (1-2 mg/kg PO q12h) and cyclophosphamide (50 mg/m 2 PO q24h for 4 consecutive days a week) for 4 weeks. The mortality rate in the P group was 20% (2 of 10), and in the PC group, the mortality rate was 38% (3 of 8). There was no difference in sequential CBC evaluations between the 2 groups. However, whereas dogs in the P group showed increases in reticulocyte count, reticulocytosis was suppressed in dogs in the PC group during the 1st week of therapy. Spherocytosis resolved more quickly in the P group (day 21) than in the PC group (day 28), but the time taken to achieve a negative Coombs' test result was comparable between groups. No difference was observed in the volume of packed red blood cells (pRBCs) given per transfusion between treatment groups, but more dogs in the PC group required a 2nd transfusion. The results of this limited study suggest that cyclophosphamide plus prednisone has no benefit over prednisone alone in the initial treatment of acute, severe idiopathic IMHA in dogs.