意大利一只缺乏红细胞吞噬症并患有严重高铁血症的狗的前体靶向免疫介导贫血的首例病例报告：诊断、治疗和临床结果

摘要(中文译文)

前体靶向免疫介导性贫血（PIMA）是狗和猫持续性非再生性贫血的一种罕见且知之甚少的原因，其特征是红细胞生成无效，经常与骨髓样本中的红细胞吞噬症（RP）有关。尽管确切的发病机制尚不清楚，但怀疑存在针对红系前体的免疫介导机制。大多数受影响的动物对糖皮质激素有反应，而在难治性病例中需要额外的免疫抑制剂。一只8岁的绝育混血母狗被转诊到兽医教学医院（意大利瓦伦扎诺），患有进行性非再生性贫血70天。初步全血细胞计数显示中度、正常红细胞、正常色素性贫血，而血清生化显示丙氨酸氨基转移酶、血清总铁和C-反应蛋白轻度升高，没有溶血迹象。骨髓细胞学检查显示红系发育不全，成熟停滞，但无RP。流式细胞术检测证实了抗RBC抗体，支持PIMA的诊断。狗用泼尼松龙（2mg/kg/天）治疗，在3天内诱导快速再生反应。由于类固醇相关的不良反应，引入了霉酚酸酯，允许逐渐减少并最终停用皮质类固醇。免疫抑制治疗后高铁血症消失。一年后，该犬在单药霉酚酸酯治疗下保持临床稳定，血液学持续缓解。该病例突出了PIMA的诊断挑战，特别是在没有RP的情况下，并强调了将这种罕见疾病纳入持续性非再生性贫血犬的鉴别诊断中的重要性，即使临床和细胞学特征不典型。

Abstract

Precursor-targeted immune-mediated anaemia (PIMA) is an uncommon and poorly understood cause of persistent non-regenerative anaemia in dogs and cats, characterised by ineffective erythropoiesis and frequently associated with rubriphagocytosis (RP) in bone marrow samples. An immune-mediated mechanism directed against erythroid precursors is suspected, although the exact pathogenesis remains unclear. Most affected animals respond to glucocorticoids, while additional immunosuppressants are required in refractory cases. An 8-year-old spayed mixed-breed female dog was referred to the Veterinary Teaching Hospital (Valenzano, Italy) with a 70-day history of progressive non-regenerative anaemia. Initial complete blood count revealed moderate, normocytic, normochromic anaemia, while serum biochemistry showed mild increases in alanine aminotransferase, total serum iron, and C-reactive protein without signs of haemolysis. Bone marrow cytology demonstrated erythroid hypoplasia with maturation arrest but no RP. Flow cytometric testing confirmed anti-RBC antibodies, supporting a diagnosis of PIMA. The dog was treated with prednisolone (2 mg/kg/day), which induced a rapid regenerative response within 3 days. Due to steroid-related adverse effects, mycophenolate mofetil was introduced, allowing gradual tapering and eventual discontinuation of corticosteroids. Hyperferraemia resolved after immunosuppressive therapy. After one year, the dog remains clinically stable on mycophenolate monotherapy with sustained haematologic remission. This case highlights the diagnostic challenges of PIMA, particularly in the absence of RP, and emphasises the importance of including this rare condition in the differential diagnosis of dogs with persistent non-regenerative anaemia, even when clinical and cytological features are atypical.

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