Intravenous Human Immunoglobulin for the Treatment of Immune-Mediated Hemolytic Anemia in 13 Dogs

Intravenous immunoglobulin (IVGG) was administered to 13 of 37 dogs with immune-mediated hemolytic anemia. All dogs received concurrent prednisone therapy, 14 dogs also received cyclophosphamide; and a single dog each received cyclosporine, azathioprines, and danazol. Dogs that responded to prednisone therapy without IVGG generally did so within 7 days (mean ± standard deviation = 5.6 ± 2.9 days). Intravenous immunoglobulin was administered after 10.4 ± 6.6 days of prednisone therapy as an intravenous infusion of 0.5 g/kg (range 0.25 to 0.73 g/kg). Eleven dogs received a single treatment, 2 dogs each received 2 treatments. No relevant adverse effects were noted. Eleven dogs had an increase in PCV of at least 4% 2.2 ±1.5 days after IVGG infusion. In 10 of these dogs, the PCV continued to increase until the time of hospital discharge. One responder died 1 hour after the increase in PCV, 1 dog was euthanized within 24 hours of IVGG administration, and 1 dog had no response over a period of 13 days. Results of this study suggest that IVGG therapy may be of value in dogs with immune-mediated hemolytic anemia that do not respond within 7 days of appropriate corticosteroid therapy.     

Immune-mediated hemolytic anemia: 70 cases (1988-1996).

Survival times and mortality rates in dogs with idiopathic immune-mediated hemolytic anemia (IMHA) have been infrequently reported in the literature. This study evaluates survival and mortality in a large group of dogs with IMHA. The association of age, sex, and breed with IMHA was evaluated by comparing affected dogs to control dogs admitted to the hospital during the same time period. Treatment regimens were reviewed to determine the effects of different agents upon survival of dogs with IMHA during hospitalization and after discharge. Median survival times for each treatment group were 57 days (prednisone), 28 days (prednisone, cyclophosphamide), 974 days (prednisone, azathioprine), 15 days (prednisone, cyclophosphamide, azathioprine), and one day (no treatment). Overall mortality rate in the population of dogs studied was 70%. Twenty-nine (41.4%) dogs either died or were euthanized while hospitalized. Forty-one (59%) dogs were discharged from the hospital. Of the dogs discharged, 10 died within the first month, another five died within three months, and another five died within a year of discharge due to assumed complications of therapy or relapses of IMHA.     

Immune-mediated hemolytic anemia in an eclectus parrot

CASE DESCRIPTION: A 2-year-old female Solomon Island eclectus parrot (Eclectus roratus) was evaluated by a veterinarian because of a 4-day history of progressive lethargy, weakness, poor appetite, and inactivity. The bird was referred to a veterinary teaching hospital for further examination. CLINICAL FINDINGS: Clinicopathologic analyses revealed that the parrot had marked regenerative anemia, autoagglutination, and biliverdinuria. Small, rounded RBCs (thought to be spherocytes) were detected in blood smears. The abnormal findings met the diagnostic criteria for dogs with primary immune-mediated hemolytic anemia. However, analyses of blood samples for lead and zinc concentrations and plasma bile acids concentrations; the use of PCR assays for Chlamydophila psittaci, psittacine circovirus 1 (causative agent of beak and feather disease), and polyomavirus; and microbial culture and Gram staining of feces did not reveal a cause for the hemolytic anemia. TREATMENT AND OUTCOME: Although administration of immunosuppressive doses of cyclosporine was initiated, there was a rapid progression of disease, which lead to death of the parrot before this treatment could be continued long-term. Lack of an identifiable underlying disease (confirmed by complete histologic examinations at necropsy) supported the diagnosis of primary immune-mediated hemolytic anemia. CLINICAL RELEVANCE: Primary immune-mediated hemolytic anemia has not been widely reported in psittacine birds. A comprehensive evaluation and complete histologic examination of tissues to rule out underlying disease processes are required to definitively establish a diagnosis of primary immune-mediated hemolytic anemia in parrots. Primary immune-me-diated hemolytic anemia should be considered as a differential diagnosis for regenerative anemia in a parrot.     

Use of therapeutic plasmapheresis in a case of canine immune-mediated hemolytic anemia

Objective – To investigate the clinical application and potential utility of plasmapheresis in canine immune-mediated hemolytic anemia.
Case Summary – A 7-year-old spayed female Maltese diagnosed with immune-mediated hemolytic anemia was initially treated with prednisone, cyclosporine, and received multiple transfusions of packed RBC. Because of the progression of clinical signs despite traditional medical therapy, plasmapheresis was initiated. Plasma immunoglobulin G and immunoglobulin M levels were measured before, during, and after treatment to help determine if there had been a significant decrease in immunoglobulin levels with plasmapheresis. Plasmapheresis was successfully performed over a 2.5-hour period in this dog with minimal complications. Hypocalcemia was identified as a known complication of circuit anticoagulation, and was corrected through calcium supplementation. Post-plasmapheresis there was a decrease in immunoglobulin G and immunoglobulin M levels, and the patient showed clinical improvement. Following discharge the dog had no known complications of therapy, and had complete resolution of the anemia.
New or Unique Information Provided – Plasmapheresis was performed successfully with minimal complications. Because transfusion requirements appeared to be reduced, and the procedure was well tolerated, there may be a place for this modality in severe cases to act as a bridge until medical therapy takes full effect. Because of the cost of performing this therapy, and the potential requirement for multiple treatments, it should be reserved for selected patients.     

Evaluation of prognostic factors, survival rates, and treatment protocols for immune-mediated hemolytic anemia in dogs: 151 cases (1993-2002)

OBJECTIVE: To evaluate prognostic factors, survival, and treatment protocols for immune-mediated hemolytic anemia (IMHA) in dogs. DESIGN: Retrospective study. ANIMALS: 151 dogs with IMHA not associated with underlying infectious or neoplastic disease. PROCEDURE: lnformation recorded from review of medical records included signalment at the time of initial evaluation; vaccination history; 30-, 60-, and 365-day follow-up outcomes; laboratory data; results of imaging studies; and necropsy findings. Dogs were grouped according to the presence of spherocytes, autoagglutination, a regenerative erythrocyte response, and treatments received (azathioprine, azathioprine plus ultralow-dose aspirin, azathioprine plus mixed-molecular-weight heparin [mHEP], or azathioprine plus ultralow-dose aspirin plus mHEP) for comparisons. All dogs received glucocorticoids. RESULTS: Cocker Spaniels, Miniature Schnauzers, neutered dogs, and female dogs were overrepresented. Alterations in certain clinicopathologic variables were associated with increased mortality rate. Rates of survival following treatment with azathioprine, azathioprine plus ultralow-dose aspirin, azathioprine plus mHEP, and azathioprine plus ultralow-dose aspirin plus mHEP were 74%, 88%, 23%, and 70%, respectively, at hospital discharge; 57%, 82%, 17%, and 67%, respectively, at 30 days; and 45%, 69%, 17%, and 64%, respectively, at 1 year. In comparison, mean survival rates at discharge and at 30 days and 1 year after evaluation collated from 7 published reviews of canine IMHA were 57%, 58%, and 34%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Treatment with a combination of glucocorticoids, azathioprine, and ultralow-dose aspirin significantly improved short- and long-term survival in dogs with IMHA.     

Immunomodulatory drugs and their application to the management of canine immune-mediated disease

This review summarises the current understanding of immune response and T cell subsets in the context of development of autoimmunity in the dog. Mode of action and rational usage in immune-mediated disease in the dog are discussed for the following drugs: glucocorticoids, azathioprine, cyclophosphamide, ciclosporin, tacrolimus, human intravenous immunoglobulin, vincristine, danazol, leflunomide, mycophenolate mofetil and liposome-encapsulated clodronate. Disease mechanisms are discussed and published evidence for drug efficacy is scrutinised for five important immune-mediated diseases: immune-mediated haemolytic anaemia, immune-mediated thrombocytopenia, myasthenia gravis, glomerulonephritis and inflammatory bowel disease. Future strategies for more refined manipulation of adverse immune responses are presented.     

Immune-mediated Hemolytic Anemia and Thrombocytopenia in the Dog: A retrospective study of 55 cases diagnosed from 1979 through 1983 at the Western College of Veterinary Medicine

All recognized cases (n = 55) of immune-mediated hemolytic anemia and immune-mediated thrombocytopenia in dogs presented to the Western College of Veterinary Medicine from 1969 through 1983 were reviewed. Specific areas of concern were: association with other conditions, therapeutic response, prognosis, relapse rate and final outcome. Of these 55 cases, 19 were immune-mediated hemolytic anemia, 26 were immune-mediated thrombocytopenia and 10 were both immune-mediated hemolytic anemia and thrombocytopenia. Females were slightly over-represented and the mean age was 6.4 years. Therapy consisted of various combinations of immuno-suppressive drugs and in some cases, whole blood transfusion and splenectomy. No firm conclusions could be made regarding therapeutic efficacy, as a result of variation in treatment protocol and the occasional unavailability of follow-up data. Well over half of all cases were diagnosed as idiopathic. Precipitating factors or diseases most frequently implicated in secondary immune-mediated thrombocytopenia or hemolytic anemia were: recent vaccination, drug therapy, obstetrical complications, stress, recent viral infection and neoplasia. Twice as many cases of immune-mediated hemolytic anemia were seen in the cooler months (October to March), although this could not be related to antibody class or thermal reactivity. Immune-mediated thrombocytopenia both as a single disease and combined with immune-mediated hemolytic anemia had no seasonal incidence. History, clinical findings and hematological and clinical chemistry findings were consistent with data previously reported, with the exception of icterus, which appeared to be of higher incidence than most reports, being present in almost 50% of immune-mediated hemolytic anemia cases. Just over half of all dogs survived, although the survival rate was highest for immune-mediated hemolytic anemia, followed closely by immune-mediated thrombocytopenia and lowest for the combined disease. Immune-mediated thrombocytopenia most frequently ran a relapsing course requiring long-term or intermittent therapy.     

Immune-mediated hemolytic anemia in a horse

An 18-year-old Quarter Horse gelding was determined to have immune-mediated hemolytic anemia after detection of autoagglutination of RBC spherocytosis as well as a positive direct Coombs test result. A lack of response to treatment with corticosteroids necessiated the administration of cyclophosphamide and azathioprine. The anemia resolved after treatment with chemotherapeutic drugs.     

Idiopathic immune-mediated hemolytic anemia: treatment outcome and prognostic factors in 149 dogs

BACKGROUND: Canine idiopathic immune-mediated hemolytic anemia (IMHA) is associated with a high mortality, especially in the 1st 2 weeks after diagnosis despite treatment. OBJECTIVES: To determine treatment outcome and identify prognostic variables in order to define areas of future research. ANIMALS: One hundred forty-nine dogs with hematocrit <30% and either a positive Coombs' test or spherocytosis and with no evidence of disease that can trigger IMHA were included. METHODS: Retrospective cohort study. All dogs were treated with prednisolone and azathioprine according to a standard protocol. Survival analysis was performed by the Kaplan-Meier method. Variables recorded at the time of diagnosis were tested as possible prognostic variables in a univariate and multivariate Cox proportional hazard model. RESULTS: The main predictors for mortality in dogs with idiopathic IMHA are the presence of increased plasma urea concentration, bands, thrombocytopenia, and petechiae at the time of diagnosis. The estimated Kaplan-Meier half-year survival was 72.6% (95% confidence interval [CI]: 64.9-81.3%). Mortality occurred mostly within the 1st 2 weeks. Cox proportional hazards analysis indicated that increased plasma urea concentration, icterus, and petechiae were the major independent predictors of mortality in the 1st 2 weeks. In most dogs that survived IMHA, a 3-month protocol of azathioprine with prednisolone maintained clinical remission. The estimated half-year survival for dogs that survived the 1st 2 weeks was 92.5% (95% CI: 86-99.3%). CONCLUSIONS AND CLINICAL IMPORTANCE: If the dogs survived IMHA, a 3-month protocol of prednisolone and azathioprine was effective with regard to survival and clinical outcome. Future research should be directed at identifying whether thrombotic tendency in dogs with IMHA is the main contributor to the development of increased plasma urea concentration, icterus, thrombocytopenia, and petechiae.     

Treatment of presumptive idiopathic immune-mediated anemia in a Holstein heifer, using blood transfusions and corticotherapy

An idiopathic immune-mediated anemia was diagnosed in a 1-year-old Holstein heifer. The diagnostic procedures, blood transfusions, use of an immunosuppressive dosage of dexamethasone, and favorable outcome are described, and idiopathic immune-mediated anemia in mammals is briefly reviewed.     

A prospective study of clopidogrel therapy in dogs with primary immune-mediated hemolytic anemia

Background: A major cause of death in dogs with primary immune‐mediated hemolytic anemia (pIMHA) is thrombotic disease. Ultralow‐dose aspirin (ULDA) is commonly used to prevent thrombosis in dogs with pIMHA; however, the efficacy of antiplatelet agents in dogs with pIMHA is unknown. Hypothesis: The use of clopidogrel (CL), alone or in combination with ULDA, would improve survival to discharge and at 90 days without important adverse effects compared with ULDA alone in dogs with pIMHA treated with standard immunosuppressive therapy. Animals: Twenty‐four client‐owned dogs with pIMHA. Methods: Prospective, positive‐controlled, unmasked clinical trial with dogs randomized in 3 treatment groups to receive PO ULDA or CL or both. Results: There was no identifiable adverse reaction, evidence of hemorrhage, or increase in transfusion requirements associated with CL therapy, either alone or combined with ULDA, compared with ULDA alone. There was no significant difference between treatment groups with respect to survival to discharge and at 90 days. Conclusions and Clinical Importance: This study suggests that CL therapy, alone or in combination with ULDA, was safe and had similar short‐term survival compared with ULDA alone in a small group of dogs with pIMHA able to tolerate oral medications and treated with standard immunosuppressive treatment.     

Treatment of immune-mediated hemolytic anemia in dogs with cyclophosphamide

A review of 60 cases of immune-mediated hemolytic anemia (IMHA) in the dog was performed in order to characterize the disease and to identify potential prognostic indicators. Dogs ranged in age from 1 to 13 years, with a mean age of 6.5 years. The 2 most commonly affected breeds were Cocker Spaniels and Labrador Retrievers. Fifty-two of the 60 dogs tested (87%) were autoagglutination positive and spherocytes were present in 45 (75%). Forty-one (89%) of 46 patients tested positive for the presence of immunoglobulin on the red blood cell surface (Coombs assay). The most common clinical signs at presentation were lethargy, weakness, pale mucous membranes, icterus, hemoglobinuria, and anorexia. PCV less than 25% was present in 59 (98%) dogs. At the time of presentation, 35 dogs (58%) had a nonregenerative anemia, whereas 25 patients (42%) had a regenerative response. Thrombocytopenia was seen in 41 (68%) dogs. Nine of 34 dogs (26%) had a prolonged prothrombin time, 19 of 34 (56%) had a prolonged activated partial thromboplastin clotting time, and 12 of 34 (35%) had abnormal fibrinogen concentrations. All dogs received prednisone at immunosuppressive doses (2.2-4.4 mg/kg PO as a single or divided dose every 24 hours) and cyclophosphamide as primary therapy. Forty-one dogs (63%) received cyclophosphamide at 50 mg/m2 q24h for 4 days, whereas 9 dogs (15%) received an initial high dose (200 mg/m2) followed by 3 days of a lower dose (50 mg/m2 q24h). No statistical difference in survival times was found for either protocol. Thirteen dogs were treated with azathioprine in addition to cyclophosphamide and prednisone. The median survival time of dogs that received all 3 drugs was 370 days as compared to 9 days for those dogs that were treated with cyclophosphamide and prednisone alone. Thirty-one (52%) dogs died from the disease, 13 (22%) dogs were alive, and 15 (25%) dogs were lost to follow-up. The median length of survival for all dogs was 21 days. Eight dogs that were discharged from the hospital suffered a relapse (PCV < 25%).     

Cyclophosphamide exerts no beneficial effect over prednisone alone in the initial treatment of acute immune-mediated hemolytic anemia in dogs: a randomized controlled clinical trial

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.     

Use of a direct enzyme-linked antiglobulin test for laboratory diagnosis of immune-mediated hemolytic anemia in dogs.

Detection of autoantibody, complement, or both bound to RBC is an essential requirement for unequivocal diagnosis of immune-mediated hemolytic anemia in dogs. An enzyme-linked antiglobulin test was adapted for laboratory diagnosis of this disease. The refinement and routine use of this assay have allowed further observation of the pathogenesis of the disease process. In particular, degree of hemolysis can be related to the degree of RBC sensitization associated with primary immune-mediated hemolytic anemia, and this correlation is highest for IgG autoantibody. Results indicate that autoantibody isotype might have an important role in the hemolytic process.     

A retrospective study of 19 cases of canine myelofibrosis

Nineteen cases of myelofibrosis were identified among 456 canine bone marrow specimens submitted for analysis. Myelofibrosis was classified as primary in I dog and as secondary in 18 dogs. Clinical conditions associated with secondary myelofibrosis included immune-mediated hemolytic anemia (n = 5), neoplasia (n = 4), and long-term drug treatment (n = 4). Drugs administered included phenobarbital, phenytoin, phenylbutazone, and colchicine. Bone marrow necrosis was observed in 5 dogs. Eight dogs were treated with immunosuppressive doses of prednisolone, and 3 were treated with erythropoietin. Half of the dogs with secondary myelofibrosis recovered from their cytopenias and were alive from 4 months to 5 years after diagnosis.     

Effect of a single plasma transfusion on thromboembolism in 13 dogs with primary immune-mediated hemolytic anemia

Thirteen dogs with primary immune-mediated hemolytic anemia received fresh-frozen plasma within 12 hours of admission, in addition to unfractionated heparin and other therapies, such as prednisone, azathioprine, and packed red blood cell transfusion. Antithrombin activity was quantified prior to transfusion and at 30 minutes and 48 hours after transfusion. Plasma antithrombin activity did not change significantly after a single plasma transfusion. There were no deaths in the first 48 hours of treatment. Thromboembolism was identified at necropsy in six of 10 dogs that died within 12 months of admission. There was no significant difference in the incidence of thromboembolism between the current treatment group and a historical control group.     

Short-term effect of cyclophosphamide and azathioprine on selected aspects of the canine blastogenic response

The short-term, in vitro responses of canine peripheral blood lymphocytes to mitogenic stimulation and serum immunoglobulin concentrations were evaluated following treatment with currently recommended doses of cyclophosphamide and azathioprine. Cyclophosphamide had no significant effect on either the serum immunoglobulin concentrations or the blastogenic response of lymphocytes to mitogenic stimulation. Serum immunoglobulin concentrations remained unchanged following azathioprine treatment. The blastogenic response was significantly suppressed following one week of azathioprine therapy and returned to baseline values one week following cessation of treatment. The response to phytohemagglutinin was most suppressed, followed, in order, by the response to concanavalin A, and to pokeweed mitogen. These results suggest that the short-term use of azathioprine, but not cyclophosphamide, in clinically used dosages, does suppress selective aspects of the canine immune system, and the T cells appear to be more susceptible than B cells to the immunosuppressive effect of this drug.     

Gingival overgrowth in a dog that received long-term cyclosporine for immune-mediated hemolytic anemia

Gingival mass lesions developed when cyclosporine was administered for 600 days to a female, 7-year-old, longhaired dachshund diagnosed with intractable immune-mediated hemolytic anemia (IMHA). Histopathology indicated hyperplastic suppurative gingivitis. As the anemia improved, the dosage of cyclosporine A (CsA) was markedly decreased, and the mass lesions decreased in size and disappeared, thus suggesting that the mass lesions were an adverse reaction to CsA.     

Anti-erythrocyte antibodies and disease associations in anemic and nonanemic dogs

BACKGROUND: Flow cytometry has been used to detect anti-red blood cell (RBC) antibodies in dogs with immune-mediated hemolytic anemia (IMHA), but the prevalence of anti-RBC antibodies in anemic and nonanemic dogs with a variety of different diseases has not been assessed previously. HYPOTHESIS: We hypothesized that anti-RBC antibodies would be more common in anemic dogs and in dogs with immune-mediated disorders and cancer. ANIMALS: Blood samples from 292 dogs were analyzed prospectively by flow cytometry for anti-RBC antibodies. METHODS: Blood samples from 147 anemic and 145 nonanemic dogs were evaluated by flow cytometry to detect surface-bound immunoglobulin (Ig) G and IgM antibodies on RBC. Disease associations with RBC antibodies were determined, as was the correlation between disease status and the percentage of Ig(+) RBC. The specificity and sensitivity of flow cytometry and clinical variables for the diagnosis of IMHA were compared by Bayesian analysis. RESULTS: Anemic dogs were significantly more likely to be positive for anti-RBC antibodies (IgG, IgM, or both) than nonanemic dogs. Anemic dogs also had significantly higher percentages of Ig(+) RBC than nonanemic dogs, whereas dogs with IMHA had significantly higher percentages of Ig(+) RBC than dogs with all other diseases. Dogs with IMHA, infectious diseases, and immune-mediated thrombocytopenia were significantly more likely to have anti-RBC antibodies than dogs with other medical or surgical diseases. CONCLUSIONS: Anemic dogs with immune-mediated diseases and infectious diseases were at the highest risk for the development of anti-RBC antibodies, and flow cytometry for the detection of IgG on RBC was highly sensitive and specific for the diagnosis of IMHA.     

Eltrombopag treatment of a dog with idiopathic aplastic pancytopenia

Idiopathic aplastic pancytopenia is an uncommon disease in dogs which results in pancytopenia and for which an immune-mediated etiology is suspected. A small number of affected dogs reported in the veterinary literature have responded to immunosuppressive medication but the prognosis generally is considered poor with a reported mortality rate of 80%. Reported response rates to immunosuppression alone in affected people are low with overall and complete responses of 65 and 10%, respectively. With the addition of eltrombopag, an orally available thrombopoietin receptor agonist, reported overall and complete response rates in people increase to 94 and 58%, respectively. Herein, we report the use of eltrombopag in a dog with idiopathic aplastic pancytopenia. Eltrombopag was started after no response was seen to treatment with prednisolone and cyclosporine. Complete remission was achieved after the addition of eltrombopag and was sustained after stopping the medication.