Acute myelogenous leukemia (AML) has a poor prognosis in patients who are ineligible for intensive chemotherapy. The combination of azacitidine and venetoclax has been shown to have high overall efficiency and remission rates, even in patients ineligible for aggressive chemotherapy. However, myelosuppression is often prolonged after treatment, and infection can also occur. Severe myelosuppression is often addressed by dose titration, but specific dose titration methods have not been clarified. We used the standard induction therapy with azacitidine plus venetoclax, and if blasts decreased to 20% or less, switched to 7+7 therapy to shorten venetoclax to 7 days starting from the next cycle. In the 19 patients we treated (median age 80 years), response rate above MLFS was 100%, CR 57.9%, CRc (CR+CRi) 78.8%, median OS 693 days, median PFS 458 days, and median OS was not reached in previously untreated patients. This indicates that 7+7 is a highly effective and well-tolerated treatment.

A 27-year-old woman was diagnosed with idiopathic thrombocytopenic purpura in the neonatal period, and was admitted to our hospital after presenting with impaired consciousness, purpura, nausea and vomiting, with a platelet count of 10×10⁹/l. Congenital thrombotic thrombocytopenic purpura (cTTP) was suspected on the basis of recurrent thrombocytopenia and impaired consciousness, so tests for ADAMTS13 activity and inhibitor were performed. ADAMTS13 activity was severely decreased, ADAMTS13 inhibitor was negative, and platelet count increased after transfusion of fresh frozen plasma. These findings and the results of genetic testing done on all family members led to a diagnosis of cTTP. cTTP requires differential diagnosis even in adults. If a patient diagnosed with ITP in childhood has a history or findings that suggest cTTP during follow-up observation, it is necessary to actively consider ADAMTS13 testing.

A 41-year-old woman with right shoulder pain was found to have multiple tumors with osteolysis and M-proteinemia. Abnormal plasma cells (CD38+, CD138+, Igλ≫κ) were detected in 1.4% of bone marrow nucleated cells, and G-banding analysis revealed a 46,XX,t (8;14), (q24;q32) karyotype in 4 of 20 cells analyzed. A biopsy specimen from an extramedullary lesion had a packed proliferation of aberrant plasmacytoid cells with positive IgH::MYC fusion signals on fluorescence in situ hybridization. The patient was diagnosed with symptomatic multiple myeloma and treated with the BLd regimen, which significantly reduced M protein levels. Extramedullary lesions were initially reduced, but increased again after four cycles. The lesions disappeared with subsequent EPOCH chemotherapy and radiation, and complete remission was confirmed. The patient was then treated with high-dose chemotherapy with autologous peripheral blood stem cell transplantation. Complete remission was maintained for over one year with lenalidomide maintenance therapy. A solitary IgH::MYC chromosomal translocation is extremely rare in multiple myeloma and may be associated with high tumor proliferative capacity, multiple extramedullary lesions, and poor prognosis. Combined therapeutic modalities with novel and conventional chemotherapy and radiation might be a promising treatment strategy for patients with this type of multiple myeloma.

An 80-year-old man with FLT3-TKD mutation-positive acute myeloid leukemia (AML) relapsed during consolidation therapy with venetoclax/azacitidine and was started on gilteritinib as salvage therapy. On the day after treatment initiation, febrile neutropenia was observed, but the fever resolved promptly after initiation of antimicrobial therapy. On the fifth day after completion of antimicrobial therapy, the patient experienced fever and watery diarrhea over 10 times a day, and a diagnosis of Clostridioides difficile infection (CDI) was made based on stool examination. The patient was treated with intravenous metronidazole, but renal dysfunction, hypotension, and hypoxemia developed, and a CT scan showed pleural and intraperitoneal effusion, significant intestinal wall thickening, and intestinal dilatation. Fidaxomicin was started under general monitoring in the intensive care unit and response was achieved. The patient was discharged from the intensive care unit on the 18th day after the onset of CDI. We report this case not only due to the rarity of fulminant CDI during AML treatment, but also because it is a valuable example of effective treatment of fulminant CDI with fidaxomicin.

Although alectinib is effective for relapsed or refractory ALK-positive anaplastic large cell lymphoma (ALCL) and has a favorable safety profile, its role as a bridging therapy for allogeneic hematopoietic stem cell transplantation (allo-HSCT) and the role of allo-HSCT itself in this setting are unknown. A 35-year-old man with ALK-positive ALCL experienced relapse after first-line therapy with CHOP. Brentuximab vedotin led to partial response and high-dose chemotherapy combined with autologous HSCT was performed. However, disease progressed 15 months after transplantation, and alectinib was initiated. Complete response (CR) was achieved after three months of treatment, and alectinib was continued for 5 months. After cessation of alectinib, allogeneic bone marrow transplantation from an HLA 1-locus mismatched unrelated donor was performed after conditioning with fludarabine, busulfan, and total body irradiation. GVHD prophylaxis consisted of tacrolimus and short-term methotrexate. The post-transplant course was unremarkable except for grade I acute GVHD. The lymphoma has not recurred for 2 years after allo-HSCT without resuming alectinib. The clinical course of our case suggests that alectinib bridging therapy and allo-HSCT are effective in relapsed/refractory ALK-positive ALCL.

Congenital protein C (PC) deficiency is one type of hereditary thrombosis. Patients with hereditary thrombosis are at high risk for thrombosis in the perioperative period, but a standard management strategy has not been established. Here we report a case of perioperative management of a fracture in a child with homozygous congenital PC deficiency. The patient was a 3-year-old boy who was diagnosed with congenital PC deficiency at birth. He sustained a traumatic supracondylar fracture of the right humerus and underwent emergency surgery. To prepare for open surgery for fixation of the fracture, warfarin was discontinued, and an activated PC (APC) concentrate was used in combination with vitamin K antagonism. However, warfarin was administered during the scheduled nail extraction because the operation was minimally invasive. No thrombotic or bleeding complications occurred in either operation. In emergency surgery in patients with congenital PC deficiency, the combination of vitamin K and APC concentrate is considered a maintenance option for PC deficiency. Postoperative PT-INR control was difficult in our patient due to the administration of vitamin K and withdrawal of warfarin, and this issue must be addressed in the future. Further case experience is desirable to standardize perioperative management.

A 44-year-old woman was diagnosed with acute myeloid leukemia (RUNX1::RUNX1T1 translocation) and received induction chemotherapy with idarubicin hydrochloride and cytosine arabinoside. The pneumonia that had been present since admission worsened, and a drug-induced skin rash appeared. On day 17, she presented with respiratory failure and shock, complicated by hemoconcentration and hypoalbuminemia. This was considered capillary leak syndrome due to pneumonia and drug allergy, so she was started on pulse steroid therapy and IVIG, and was intubated on the same day. On day 18, venovenous-extracorporeal membrane oxygenation (VV-ECMO) was started due to worsening blood gas parameters despite ventilatory management. Bronchoalveolar lavage fluid was serous, and both blood and sputum cultures yielded negative. The patient was weaned from VV-ECMO on day 26 as the pneumonia improved with recovery of hematopoiesis. She was disoriented, and a CT scan on day 28 revealed cerebral hemorrhage. Her strength recovered with rehabilitation. After induction chemotherapy, RUNX1::RUNX1T1 mRNA was not detected in bone marrow. The patient received consolidation chemotherapy, and has maintained complete remission. Severe respiratory failure during induction chemotherapy for acute leukemia can be fatal, but VV-ECMO may be lifesaving.

A 3-year-old boy was referred to our hospital with splenomegaly. Blood tests revealed hyperleukocytosis and bone marrow examination showed major BCR::ABL1 fusion, leading to the diagnosis of chronic myelogenous leukemia (CML). Due to intolerance, the tyrosine kinase inhibitor (TKI) was changed from imatinib to dasatinib to nilotinib. The patient achieved molecular remission but became markedly short in stature, measuring 129.3 cm (height standard deviation score [SDS] −3.3) at the age of 12. TKI therapy was discontinued at age 12 years and 10 months, which was 9 years and 8 months after the start of TKI and 1 year and 6 months after achievement of MR4.0, as discontinuation before epiphyseal closure would not improve short stature. At 2 years and 6 months after discontinuation, the patient’s height improved to 156.1 cm (SDS−2.0) without relapse. Growth suppression by TKIs is a problem in the management of pediatric CML. This case illustrates how improvement in severe short stature can be achieved by discontinuing TKI therapy before epiphyseal closure.

Relapse or progressive disease after chimeric antigen receptor T-cell (CAR-T) treatment remains a major issue for poor-risk aggressive large B-cell lymphoma. However, limited data are available on post-CAR-T use of polatuzumab vedotin. Here we describe the case of a patient with diffuse large B-cell lymphoma (DLBCL) who experienced relapse three months after CD19-directed CAR-T therapy with tisagenlecleucel. However, the relapsed lesions rapidly disappeared following treatment with polatuzumab vedotin and rituximab. Notably, long-term remission was achieved without severe cytopenia, infections or peripheral neuropathy, showing the therapeutic benefit of polatuzumab vedotin for CAR-T failure.

The transcription factor GATA-1 is essential for erythroid differentiation. Recently, FAM210B, which encodes a mitochondrial inner membrane protein, has been identified as a novel target of GATA-1. To clarify the role of FAM210B, we depleted endogenous FAM210B in human iPS-derived erythroid progenitor (HiDEP-1) cells, and found that erythroid differentiation was more pronounced in the FAM210B depleted cells. Comprehensive metabolite analysis revealed a decline in mitochondrial function accompanied by increased lactate production, indicative of anaerobic glycolysis. Mass spectrometry revealed that FAM210B could interact with multiple subunits of mitochondrial ATP synthases, such as subunit alpha (ATP5A) and beta (ATP5B). Our results suggested that FAM210B contributes prominently to erythroid differentiation by regulating mitochondrial energy metabolism. This review will discuss the potential association between mitochondrial metabolism and erythropoiesis.