後天性赤芽球癆

Pure red cell aplasia (PRCA) is a rare hematologic disorder characterized by a marked decrease in reticulocytes and erythroid cells. For a long time up until today, PRCA has been clinically divided into idiopathic, thymoma-associated, and T-large granular lymphocytic leukemia (T-LGLL)-associated acquired PRCA (aPRCA). We herein report the case of a 90-year-old woman diagnosed with aPRCA secondary to an indolent mature T-cell malignancy atypical for T-LGLL. No apparent large granular lymphocytes were detected, tests for cytotoxic antigens, including granzyme B and perforin, were negative, and no STAT3 mutations were detected. Therefore, a careful evaluation of the underlying disease accompanied by aPRCA is required.

BACKGROUND: Cyclosporine A (CsA) is the standard first-line treatment for acquired pure red cell aplasia (PRCA), but outcomes vary. Effective salvage strategies for CsA-refractory patients, particularly those with complex secondary subtypes, remain inadequately defined. Additionally, the clinical utility of STAT3/5b mutations in guiding treatment selection remains unclear. OBJECTIVES: To evaluate the efficacy of second-line sirolimus for the treatment of PRCA and explore the possible genetic predictors for the response. DESIGN: This study was a retrospective, single center, comparative study. METHODS: Patients with acquired PRCA treated between 2021 and 2025, including 36 patients who received first-line CsA and 22 patients who switched to sirolimus due to lack of response or intolerance. Clinical outcomes, including overall response rate (ORR) and time to response (TTR), were compared between primary and secondary PRCA. STAT3/5b mutation status was also analyzed to assess its predictive value for treatment response. RESULTS: The ORR for first-line CsA was 25.0% (9/36), with significantly higher efficacy observed in primary cases (42.1%, 8/19) than in secondary cases (5.9%, 1/17; p = 0.015). In the salvage sirolimus group, the ORR was 54.5%, demonstrating efficacy in both primary (37.5%, 3/8) and secondary cases (64.3%, 9/14). The median TTR did not differ significantly between sirolimus and CsA (3.0 vs. 1.5 months, p = 0.150), and both agents achieved sustained remission in responders. Regarding genetic predictors, no responses to CsA were observed in patients harboring STAT3/5b mutations (0/6). In contrast, sirolimus elicited responses in both mutated (3/6) and wild-type (4/5) patients, indicating efficacy irrespective of STAT3/5b status. CONCLUSIONS: CsA is effective in primary PRCA, whereas sirolimus demonstrates efficacy in both primary and secondary cases regardless of STAT3/5b status. Early genetic profiling may facilitate the identification of patients who may not fully response to CsA and potentially earlier transition to sirolimus salvage therapy.

The use of immune checkpoint inhibitors (ICIs) have transformed oncological care. In this 'nutshell review', we summarize the most common haematological immune-related adverse events (irAEs) associated with checkpoint inhibitors. We also outline management strategies and address current evidence regarding ICI rechallenge.

Anemia is a nearly universal complication of chronic kidney disease (CKD). While erythropoiesis-stimulating agents (ESAs) are the standard of care, they rarely induce acquired pure red cell aplasia (PRCA) via neutralizing anti-erythropoietin (anti-EPO) antibodies. Diagnosis is often delayed as clinical focus frequently shifts toward more common causes of acute anemia, such as hemorrhage. An 88-year-old male on maintenance hemodialysis presented with a precipitous hemoglobin drop to 6.8 g/dL. Investigation revealed replete hematinics but profound reticulocytopenia. After excluding occult gastrointestinal bleeding, hemolysis, and nutritional deficiencies, a bone marrow biopsy demonstrated isolated erythroid aplasia with preserved myeloid and megakaryocytic lineages, leading to a diagnosis of PRCA. Anti-EPO antibody testing was not performed, which limits definitive etiological confirmation. Due to the high risk of immunosuppression in an elderly patient and the limited accessibility of hypoxia-inducible factor-prolyl hydroxylase inhibitors (HIF-PHIs), management was restricted to ESA cessation and supportive transfusions. This case highlights the diagnostic approach for severe anemia and the significance of profound reticulocytopenia in PRCA. The definitive hallmark remains the detection of circulating anti-EPO antibodies paired with a bone marrow study demonstrating near-total depletion of erythroid precursors, but preserved myeloid and megakaryocyte lineages. Management includes the permanent cessation of ESAs, immunosuppression to reduce circulating antibodies, and supportive blood transfusions. In chronic hemodialysis patients, early recognition of iatrogenic PRCA is essential to prevent the continued administration of potentially harmful ESAs and to facilitate a transition toward alternative therapies, such as HIF-PHIs.

We describe a patient with long-standing rheumatoid arthritis (RA) who developed severe refractory transfusion-dependent anaemia lasting several months following treatment with a JAK1 inhibitor (Filgotinib). The patient proceeded with extensive investigations, including bone marrow assessment, and was initially diagnosed with Filgotinib-associated anaemia. However, despite stopping this agent, the anaemia persisted with fluctuating reticulocyte count resulting in multiple hospital admissions. Although the anaemia was initially attributed to Filgotinib, its persistence alongside delayed reticulocytopenia, ultimately led to a diagnosis of acquired Pure Red Cell Aplasia more than 12 months later. Complete remission was achieved with prednisolone + ciclosporin A. This case underscores the need to consider PRCA in RA patients on JAK inhibitors even with initially normal reticulocyte counts, as these agents may transiently mask underlying aplasia.