Clinical features of precursor-targeted immune-mediated anemia in dogs: 66 cases (2004–2013)

Abstract

OBJECTIVE To characterize the clinical features of dogs with precursor-targeted immune-mediated anemia (PIMA). ANIMALS 66 dogs with PIMA. PROCEDURES Electronic record databases of a teaching hospital were searched to identify dogs with a diagnosis of nonregenerative anemia between 2004 and 2013. Inclusion criteria included persistent nonregenerative anemia (Hct ≤ 30% and reticulocyte count < 76,000 reticulocytes/μL), cytologic findings supportive of ineffective bone marrow erythropoiesis, and absence of underlying disease. Information regarding clinical signs, clinicopathologic findings, treatment, and outcome was extracted from records of eligible dogs. A regenerative response was defined as a reticulocyte count > 76,000 reticulocytes/μL or sustained increase in Hct of > 5%. Remission was defined as a stable Hct ≥ 35%. RESULTS The median Hct was 13%, and reticulocyte count was 17,900 reticulocytes/μL. Rubriphagocytosis was identified in bone marrow aspirate samples from 61 of 66 dogs. Collagen myelofibrosis was detected in bone marrow biopsy specimens obtained from 31 of 63 dogs. Immune-mediated targeting of mature erythrocytes was uncommon. All dogs received immunosuppressive therapy. Fifty-five dogs developed a regenerative response at a median of 29 days, and 40 of those dogs went into remission at a median of 59 days after PIMA diagnosis. Thromboembolic events were confirmed for 9 dogs and were associated with a decreased survival time. Median survival time was 913 days for all dogs. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that most dogs with PIMA responded to prolonged immunosuppressive therapy. Studies to determine optimal immunosuppressive and thromboprophylactic protocols for dogs with PIMA are warranted.

Breed predispositions, clinical findings, and prognostic factors for death in dogs with nonregenerative immune‐mediated anemia

“…The diagnosis of immune‐mediated hemolytic anemia (IMHA) can be made confidently in dogs that fulfill the criteria outlined recently in the American College of Veterinary Internal Medicine (ACVIM) consensus statement 1 . Within 5 days of becoming anemic, dogs with IMHA typically develop erythroid regeneration 2 ; however, 30% to 55% remain nonregenerative with a corrected reticulocyte percentage (CR%) ≤1.0, which has been ascribed to destruction of erythroid progenitors by phagocytes in the bone marrow (BM) (rubriphagocytosis) 1,3‐7 . Similar rubriphagocytosis occurs also in dogs with nonregenerative anemia that lack evidence of peripheral immune‐mediated erythroid destruction or hemolysis, recently described as precursor‐targeted immune‐mediated anemia (PIMA) 3,8 .…”

Clinical and clinicopathological features and outcomes of Miniature Dachshunds with bone marrow disorders

“…On signalment, spayed females were significantly overrepresented in MDs. In previous studies, spayed females were also significantly predisposed to be diagnosed with NRIMA, PRCA, and PIMA [2,17,22], but the underlying causes have been unknown.…”

“…As a result, MD was identified as a predisposed breed of non-neoplastic bone marrow disorders in Japan. In the United States, Miniature Dachshunds were reported as a predisposed breeds for PIMA [2]. It was reported that MD was a breed commonly predisposed to inflammatory colorectal polyps and sterile panniculitis, which were rare in other breeds [16,23].…”

“…It has been previously reported in the United States that Labrador Retrievers and Miniature Dachshunds are predisposed to NRIMA and PIMA, respectively [2,17].…”

“…[2][3][4][5][6][7][8][9][10][11][12][13][14], and the median blast cell ratio was 1% (range: 0.2-2.6%). Erythroid cells were hypercellular in 6 dogs, normocellular in 5 dogs, and hypocellular in 6 dogs.…”