Pure red cell aplasia (PRCA) is characterised by normocytic normochromic anaemia, reticulocytopenia and reduced erythroid precursors in bone marrow. PRCA as an immune-related adverse event secondary to immune checkpoint inhibitor (ICI) therapy is rare. Steroids are usually used first line to treat ICI-induced PRCA. Here, we report a case of ICI-induced PRCA with no response to steroids but where intravenous (IV) immunoglobulin was successfully used second line. ICI therapy was reinitiated following PRCA resolution. PRCA recurrence did not occur.

Monoclonal gammopathy-associated pure red cell aplasia (MG-PRCA) is characterized by the absence or pronounced hypoplasia of erythroid precursors in the bone marrow, causing reticulocytopenia and a normocytic, normochromic anaemia in a patient with a monoclonal plasma cell dyscrasia. We report here on the successful treatment of MG-PRCA with isatuximab, pomalidomide, and dexamethasone after multiple lines of immunosuppressive and anti-plasma cell-directed treatments.

Good syndrome (GS) is a rare condition characterized by thymoma and immune deficiency with a poorly understood mechanism in which patients have reduced immunoglobulin levels and circulating B-cells along with impaired T-cell function. GS is often accompanied by autoimmune and inflammatory conditions, and in this report, we present a case of refractory oral lichen planus (OLP) preceding the diagnosis of GS. In this case, a patient with a history of OLP was diagnosed with GS and common variable immunodeficiency (CVID) following thymectomy and was treated with intravenous immunoglobin (IVIG). Additionally, he was found to have pure red cell aplasia managed with cyclosporine. His oral symptoms worsened, and he presented to dermatology. Treatment was initiated with topical clobetasol and tacrolimus for his OLP, and fluconazole was started for concomitant oral candidiasis. His OLP has remained under satisfactory control with this regimen; however, he requires close surveillance for malignancy given his increased risk of oral squamous cell carcinoma (OSCC) with immunosuppression and active OLP. Although rare, clinicians should be aware of GS and its association with erosive OLP along with the heightened risk of infection in these patients.

Adenosine deaminase 2 (ADA2) deficiency is an autosomal recessively inherited autoinflammatory disorder caused by loss-of-function mutations in the ADA2 gene. Although the pathogenesis involves the triggering of a proinflammatory cascade due to increased production of inflammatory cytokines such as tumor necrosis factor (TNF)-α and dysregulation of neutrophil extracellular trap formation resulting from an excess accumulation of extracellular adenosine, the pathogenetic mechanism still needs further clarification due to the broad clinical spectrum. In addition to the initially described vasculitis-related symptoms, hematological, immunological, and autoinflammatory symptoms are now well recognized. The diagnosis is made by demonstration of pathogenic variants of ADA2 with biallelic loss of function and identification of low plasma ADA2 catalytic activity. Currently, TNF-α inhibitors are the treatment of choice for controlling vasculitis manifestations and preventing strokes. However, in patients presenting with severe hematologic findings, TNF-α inhibitors are not the treatment of choice and hematopoietic stem cell transplantation has been shown to be successful in selected cases. Recombinant ADA2 protein and gene therapy are promising treatment modalities for the future. In conclusion, ADA2 deficiency has a broad phenotype and should be considered in the differential diagnosis of different clinical situations. In this review, we summarize the disease manifestations of ADA2 deficiency and available treatment options.
Adenozin deaminaz 2 (ADA2) eksikliği, ADA2 genindeki işlev kaybı mutasyonlarının neden olduğu otozomal resesif geçişli otoenflamatuvar bir hastalıktır. Patogenez, tümör nekroz faktörü (TNF)-alfa gibi enflamatuvar sitokinlerin üretiminin artması nedeniyle proinflamatuvar bir kaskadın tetiklenmesini ve ekstraselüler adenozinin aşırı birikiminden kaynaklanan nötrofil ekstraselüler tuzak oluşumu disregülasyon sürecini içermesine rağmen, geniş klinik spektrum nedeniyle patogenetik mekanizmanın hala daha fazla açıklığa kavuşturulması gerekmektedir. Başlangıçta tanımlanan vaskülitle ilişkili semptomlara ek olarak, hematolojik, immünolojik ve otoinflamatuar semptomlar da artık iyi tanınmaktadır. Tanı, ADA2’nin biallel fonksiyon kaybı ile patojenik varyantlarının gösterilmesi ve düşük plazma ADA2 katalitik aktivitesinin tanımlanması ile konur. Günümüzde TNF alfa inhibitörleri, vaskülit belirtilerini kontrol altına almak ve felçleri önlemek için tercih edilen tedavidir. Şiddetli hematolojik bulgularla başvuran hastalarda, TNF alfa inhibitörleri tercih edilen tedavi değildir ve hematopoetik kök hücre naklinin seçilmiş vakalarda başarılı olduğu gösterilmiştir. Rekombinant ADA2 proteini ve gen tedavisi gelecek için umut verici tedavi yöntemleridir. Sonuç olarak, ADA2 geniş bir fenotipe sahiptir ve farklı klinik durumlarda ayırıcı tanıda göz önünde bulundurulmalıdır. Bu derlemede,ADA2 eksikliğinin hastalık belirtilerini ve mevcut tedavi seçeneklerini özetlemeyi amaçladık.

We report a case series of two patients with chronic kidney disease (CKD) who developed erythropoietin-induced pure red cell aplasia following a change in erythropoietin preparation. Both patients responded well to immunosuppressive treatments, but unfortunately developed severe infections as a result of being immunosuppressed.

Acquired pure red cell aplasia (PRCA) is a rare syndrome characterized by normocytic normochromic anemia with severe reticulocytopenia and absence of erythroid precursors in the bone marrow. For refractory PRCA patients, the low response rate and high toxicity of alternative therapies pose a great challenge. T-cell large granular lymphocyte (T-LGL) leukemia is one of the most common conditions in secondary PRCA and also the most difficult form to manage with an inferior treatment response to other secondary PRCA forms. T-LGL leukemia exhibits sustained activation of the intracellular JAK-STAT signaling pathway. We herein report a case of PRCA associated with T-LGL leukemia that had been refractory to multiple lines of therapies and was successfully treated by ruxolitinib. The patient achieved complete remission and tolerated ruxolitinib well without occurrence of neutropenia or thrombocytopenia. This preliminary finding favors ruxolitinib as a potential salvage therapy for refractory PRCA associated with T-LGL leukemia.

Good\'s syndrome is a pathologic condition characterized by thymoma and immunoglobulin disorder. Here, we report a rare case of a patient with Good\'s syndrome with simultaneous pure red cell aplasia (PRCA) and subclinical myasthenia gravis with detectable serum anti-acetylcholine receptor antibody (AChR Ab). While thymectomy did not result in the improvement of any paraneoplastic syndromes, cyclosporine A (CsA) treatment successfully improved PRCA; however, hypoglobulinemia was not recovered, and anti-AchR Ab did not disappear by CsA treatment in our case. A review of the literature on simultaneous Good\'s syndrome with PRCA also suggested the efficacy of CsA on PRCA but not hypoglobulinemia, suggesting the distinct underlying mechanisms between these two paraneoplastic symptoms with thymoma. Future research is needed to understand the mechanism underlying this rare pathologic condition and to generate appropriate treatment.

BACKGROUND: At present, cyclosporine (CsA) is the first-line treatment for Pure Red Cell Aplasia (PRCA), but CsA administration can be associated with a number of side effects due to its high toxicity. Therefore, it is urgent to explore a safe and effective treatment for elderly patients who cannot be treated with conventional doses of CsA, especially those with multiple complications. Allogeneic Stem Cell Transplantation (ASCT) for PRCA is a promising treatment, but reports of using umbilical cord blood (UCB) are very rare.
METHODS: In this report, UCB and umbilical cord mesenchymal stem cells (UC-MSCs) combined with low-dose CsA (1-3mg/kg/d) were used to treat 3 elderly patients who were diagnosed with PRCA combined with multiple complications in heart, lung, and renal. The treatments were successful without complications, and 12 months after stem cell infusion, the blood tests of the patients came normal. Moreover, the function of the liver, heart, and kidney continued to be stable.
CONCLUSIONS: This report provides an effective regimen of using UCB and UC-MSCs combined with low-dose CsA (1-3 mg/kg/d) to treat PRCA, especially for elderly patients with multiple complications who cannot use the conventional dosage.

UNASSIGNED: Riboflavin transporter deficiency (RTD) is a rare genetic disorder that affects riboflavin transport, leading to impaired red blood cell production and resulting in pure red cell aplasia. Recognizing and understanding its clinical manifestations, diagnosis, and management is important.
UNASSIGNED: A 2-year-old patient presented with pure red cell aplasia as the primary symptom of RTD. After confirming the diagnosis, rapid reversal of anemia was achieved after high-dose riboflavin treatment.
UNASSIGNED: RTD often has an insidious onset, and neurological symptoms appear gradually as the disease progresses, making it prone to misdiagnosis. Genetic testing and bone marrow biopsy can confirm the diagnosis.

Pure red cell aplasia (PRCA) is a rare bone marrow (BM) disorder characterized by ineffective erythropoiesis, reduced reticulocyte count, normocytic anemia, and the absence of erythroid precursors. Here, we present a rare instance of PRCA occurring after ABO-matched allo-HSCT in a refractory/relapsed acute myeloid leukemia (R/R AML) patient. In this case, the patient received a combination treatment of Gilteritinib, Venetoclax, and Azacitidine. Remarkably, this treatment not only reduced myeloblasts but also facilitated the restoration of erythroid hematopoiesis.