This is a prospective study conducted to determine the level of anti-spike IgG to SARS-CoV-2 2-6 weeks following the BNT162b2 vaccination in 125 patients with hematological disorders. Compared with healthy controls, patients with malignant lymphoma had lower rates of seropositivity and lower levels of antibody titer. Furthermore, patients who received rituximab (R)-containing chemotherapy had lower antibody titers than those who were not treated with R or who had completed R-containing chemotherapy more than 9 months earlier. Despite having 71% IgG-seropositivity, patients with multiple myeloma had lower antibody titers than the control group. Furthermore, patients receiving daratumumab-containing chemotherapy had lower antibody titers than those not receiving treatment. Moreover, patients with acute myeloid leukemia or myelodysplastic syndrome had lower antibody titers than the control group. Overall, the number of peripheral blood lymphocytes was significantly correlated with IgG titers, with seropositive patients having more peripheral blood lymphocytes than seronegative patients. Patients with severe immunosuppression, such as those with hematological disorders, often have impaired seroconversion with COVID-19 vaccination that should be taken into consideration by clinicians.

In about half of the cases, autoimmune hemolytic anemia (AIHA) is secondary to an underlying disease, often due to paraneoplastic syndromes. Recently, the number of patients developing metachronous multiple primary malignant tumors (MPMTs) has been increasing due to the aging of the population and the longer survival times of those with malignant tumors. A 78-year-old woman was diagnosed with sigmoid colon cancer in May 2017 and with warm AIHA in October 2017. She received prednisolone for her warm AIHA treatment, which relieved her anemia symptoms. In January 2020, she had a warm AIHA relapse and received PSL again. In May 2020, she was diagnosed with peritonitis due to a small intestinal perforation and underwent laparoscopic partial resection of the small intestine. Subsequently, she was diagnosed with diffuse large B-cell lymphoma. It is important to consider the possibility of MPMTs and perform the appropriate examinations to determine whether malignant tumors are present in patients with a history of malignant tumors and a long history of AIHA relapse.

Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by hemolysis, thrombosis, and bone marrow failure. Infection, pregnancy, and surgical operation have the potential to evoke severe episodes of hemolysis and thrombosis. Therefore, the use of an antibody agent against complement component 5 (C5), eculizumab, one day before the operation is recommended. Ravulizumab is a newly approved long-acting antibody agent against C5. Thus, little is known about perioperative management with ravulizumab. We experienced a 43-year-old female patient who safely underwent laparoscopic cholecystectomy under ravulizumab treatment for PNH. Ravulizumab was administered one day before the operation. Laparoscopic cholecystectomy for cholelithiasis was performed under intravenous anesthesia, intermittent air compression of the lower extremities, and low pneumoperitoneum pressure. Additionally, heparin was administered, and the patient left the sickbed early without significant postoperative complications. Like eculizumab, complement inhibition by ravulizumab is also considered effective in the perioperative management of patients with PNH. However, close cooperation with surgeons and anesthesiologists and careful management based on clinical symptoms and laboratory data such as LDH, CH50, and D-dimer are essential.

A 73-year-old woman was hospitalized with sudden chest pain and hematemesis. Chest computed tomography and upper gastrointestinal endoscopy revealed an idiopathic submucosal hematoma from the cervical esophagus to the esophagogastric mucosal junction. Idiopathic esophageal submucosal hematoma is often prone to a bleeding tendency of an underlying disorder. The patient had a history of essential thrombocythemia (ET) and was taking aspirin. She successfully recovered after aspirin discontinuation and conservative treatment; however, died of cardiopulmonary arrest in the ward on day 9 of hospitalization. The autopsy revealed that the cause of death was pulmonary thromboembolism. This is the first report of ET with submucosal hematoma of the esophagus. The possibility of an esophageal submucosal hematoma should be considered when patients with ET complain of chest pain since ET and treatment with aspirin are considered risk factors for bleeding. Additionally, close attention should be focused on the risk of developing thrombosis if a patient with myeloproliferative neoplasm is required to discontinue antithrombotic therapy due to a bleeding event.

Inotuzumab ozogamicin (InO) was administered in three cases of relapsed/refractory adult acute lymphoblastic leukemia (ALL) before allogeneic hematopoietic stem cell transplantation (allo-SCT). One case developed extremely severe sinusoidal obstruction syndrome (SOS) but recovered after receiving defibrotide therapy. A gap of 63 days in the SOS case was noted from the last administration of InO to allo-SCT, the duration was 133 and 86 days for the other two cases, and the remaining risk factors for SOS were comparable in the three cases. In contrast to gemtuzumab ozogamicin (GO), the interval between InO exposure and allo-SCT has not been reported as a risk for SOS. Nevertheless, this case suggests that the intervals should be as long as possible.

Thrombotic thrombocytopenic purpura (TTP) is an extremely rare and fatal thrombotic disorder characterized by impaired enzyme activity of von Willebrand factor cleaving protease, also known as ADAMTS13. Immune-mediated TTP (iTTP) is an acquired form of TTP caused by the production of auto-antibodies against ADAMTS13. The pathophysiology of autoimmune disorders is multifactorial, with several human leukocyte antigen (HLA) alleles identified as a genetic risk factor for autoimmune diseases known as susceptible HLA. In the early 2010s, three distinct European groups revealed that DRB1^*11 is one of the most susceptible alleles in acquiring iTTP among Caucasians based on HLA typing data. Several in silico predictions for allele-restricted ADAMTS13 epitopes against T cells are made in this context, followed by an in vitro validation employing mass spectrometry using eluted peptides and T-cell assays. However, similar analyses in a genetically distinct Japanese population have not yet been conducted. We used next-generation sequencing to perform HLA typing for 52 Japanese patients with iTTP from 19 institutes. Our detailed analysis revealed that the specific allele DRB1^*08:03 was identified as a genetic risk factor for iTTP in Japanese patients, but there were no statistically significant differences in the allele frequency of DRB1^*11 between iTTP and healthy controls.

Immune reactions promote not only graft-versus-tumor events but also graft-versus-host disease (GVHD) characterized by the activation of T-cells and antigen-presenting cells. Recent studies have unveiled the effects of microbial flora on GVHD and brought the mechanism other than immune cells. The role of tissue-intrinsic factors contributes to target-tissue resilience, repair, and regeneration and mitigates the severity of GVHD without altering alloreactive immune cells. Antibiotics, specific bacteria, and low microbiota diversity are identified as risk factors for GVHD and mortality. The current focus has shifted to target-tissue homeostasis in GVHD. Most of the gut microbiota symbiotically colonize the gut, and this homeostasis is finely tuned in the gastrointestinal tract, which has a relatively hypoxic environment dominated by anaerobic organisms. Therefore, intestinal epithelial cells (IECs) are uniquely adapted to this hypoxic environment, and cells programmed by “physiological hypoxia” tonally regulate barrier function with commensal bacteria. Metabolic changes in IECs post allo-HCT can affect the gut environment, leading to dysbiosis. This review focuses on the role of metabolism in IECs with microbiota and microbial metabolites in the GVHD setting to promote tissue tolerance.

Diagnosis and classification of hematological diseases have been based on morphological and immunological findings, but the emergence of next-generation sequencing (NGS) technology has highlighted the importance of genomic alterations. With the advent of this novel technology, numerous genetic alterations have been identified in hematological malignancies. In fact, more than 300 genetic alterations have been listed in the latest WHO classification, such as NPM1 mutation, for the subcategorization of acute myeloid leukemia. In addition, increasing evidence has suggested that combining genetic information with clinical factors improves prognostic prediction in several hematological malignancies. Although NGS-based genomic profiling has been used to provide precision medicine in solid cancers, no comprehensive genomic profiling test for hematological diseases is covered by public health insurance both in Japan and abroad. Identification of targetable alterations is the main purpose of NGS-based genomic profiling in solid cancers, whereas genetic information is useful not only for treatment stratification but also for diagnosis and prognostic prediction. In addition, genetic profiles of solid and hematological malignancies are quite different. Therefore, the development of a comprehensive genomic profiling test for hematological disease is imperative. Here, we discuss the clinical utility of a comprehensive genomic profiling test for hematological malignancies with an emphasis on diagnosis and prognostic prediction.

Next-generation sequencing (NGS)-based multigene panel testing enables assessment of the mutational status of a few hundred genes associated with cancer pathogenesis. Although such tests have been approved by the Pharmaceuticals and Medical Devices Agency for use in patients with treatment-refractory solid tumors,there are no currently available tests for hematologic malignancies. The resultant information from these panel tests is primarily used to identify a potential treatment regimen or targeted therapy for solid tumors. However, genome profiling in hematologic malignancies also guides the clinical management of patients by providing diagnostic and prognostic information. This review summarizes the potential advantage of NGS-based multigene panel tests over conventional tests to determine therapeutic strategies for hematologic malignancies.

Gene panel test, which has been used in the field of solid tumors, is expected to be introduced in the field of hematopoietic tumors in the near future. Unintended germline variants may be detected due to the comprehensive nature of the gene panel test, and these are called “secondary findings.” Additionally, it sometimes reveals that a person has germline variants that predispose the carriers to develop the disease. There are several impeding issues to be addressed regarding these germline variants, including detection methods, obtaining informed consent, scope of variants to be disclosed, and genetic counseling methods. In the field of hematopoietic tumors, the problem is further complicated by the possibility of detecting germline variants in donors because allogeneic hematopoietic stem cell transplantation constitutes an important treatment modality in this field. Thus, this paper aims to outline the issues related to germline variants in gene panel tests, which were discussed at the symposium “NGS-based multi-gene panel testing in hematology/oncology” at the annual meeting of the Japanese Society of Hematology in 2021.

Genes that regulate immunological activities are transiently suppressed by epigenetic modification during the germinal center reaction of B cells and reactivated when B cells exit the germinal center. Mutations of EZH2 and other epigenetic modifier genes are frequently involved in the pathogenesis of follicular lymphoma and lead to silencing of the genes necessary for exiting the germinal center. Tazemetostat, an EZH2 inhibitor, has been approved for the treatment of follicular lymphoma with EZH2 gain-of-function mutations in Japan. Tazemetostat restores the expressions of MHC and CD58 in lymphoma cells and synergistically enhances the immune reactions of T and natural killer cells against lymphoma cells. Tazemetostat also induces lymphoma cells to secrete CCL17/TARC and enhances T-cell migration. CD58 and CCL17 are known to play central roles in the formation of T-cell-rich tumor microenvironment of Hodgkin lymphoma. We found that tazemetostat enhances the expression of genes overexpressed in Hodgkin/Reed—Sternberg cells. Epigenetic modifiers and new molecular targeted therapies are expected to provide new insights into the pathogenesis of lymphoma and mechanisms determining the histology of lymphoma.