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COVID-19 is a viral infection characterized by a cytokine storm similar to that in acute respiratory distress syndrome (ARDS). Neutrophils and monocytes are known to play an important role in tissue damage in ARDS. COVID-19 has been reported to be more severe in patients with hematological malignancies; however, there are few reports of COVID-19 in patients with aplastic anemia. Moreover, how aplastic anemia affects COVID-19 remains unclear. Here, we report the case of a COVID-19 patient with aplastic anemia who had high serum IL-6 levels but did not progress to the severe form of COVID-19. We inferred that severe neutropenia and monocytopenia due to aplastic anemia could contribute to a mild form of COVID-19, although a risk of more severe secondary bacterial infections exists.

Myelodysplastic syndrome (MDS) is a group of clonal hematopoietic disorders characterized by peripheral cytopenia and morphological abnormalities in hematopoietic cells, i.e., myelodysplasia. Aging-related somatic variants acquired in the hematopoietic cells are associated with MDS pathogenesis in adults. However, pediatric MDS often occurs because of germline predispositions. Myelodysplasia can be observed in not only MDS but also other hematopoietic and non-hematopoietic disorders, such as infections and primary immunodeficiencies. Therefore, careful differential diagnosis between MDS and other diseases is necessary. The bone marrow histopathology should be evaluated for accurate differentiation of MDS without excess blasts from aplastic anemia and MDS with excess blasts from acute myeloid leukemia. The treatment strategy for childhood MDS differs based on disease subtypes. The clinical courses of pediatric MDS without excess blasts are heterogeneous; therefore, it is crucial to assess the prognostic values of clinical and cytogenetic findings. In contrast, allogeneic hematopoietic cell transplantation should be considered as the only curative option for pediatric MDS with excess blasts.

Inherited bone marrow failure syndromes comprise a series of disorders caused by various gene mutations. Genetic tests were formerly difficult to perform because of the large size and number of causative genes. However, recent advances in next-generation sequencing has enabled simultaneous testing of all causative genes to be performed at an acceptable cost. We collaboratively conducted a series of whole-exome sequencing studies of patients with inherited bone marrow failure syndromes and discovered RPS27/RPL27 and FANCT as causative genes of Diamond-Blackfan anemia and Fanconi anemia, respectively. Furthermore, we established a target gene sequencing system to cover 189 genes associated with pediatric blood diseases to assist genetic diagnoses in clinical practice. In this review, discovery of new causative genes and possible roles of next-generation sequencing in the genetic diagnosis of inherited bone marrow failure syndromes are discussed.

The inherited bone marrow failure syndromes (IBMFS) are rare disorders in which there is usually some form of bone marrow failure and typical changes in physical appearance, associated with a family history of the same disorder. Patients with IBMFS have a very high risk of developing myelodysplastic syndrome, acute myeloid leukemia, and solid tumors. The latest technology applied to the molecular pathogenesis of these disorders has led to identification of specific genetic mutations and now facilitates determining the appropriate diagnosis and management of afflicted patients. In this section, we describe physical and laboratory findings and management of the major IBMFS: Fanconi anemia, dyskeratosis congenita, Shwachman-Diamond syndrome, and Diamond Blackfan anemia. We also discuss their possible implications in the clinical features of Japanese patients.

The research committee for idiopathic hematopoietic disorders, which has been supported by the government over the past 35 years, has recently worked out a series of reference guide for the management of diseases under investigation to provide aids for better understanding of pathophysiology of diseases and appropriate clinical decision making. Such attempts covered aplastic anemia, Fanconi anemia, pure red cell aplasia, autoimmune hemolytic anemia, paroxysmal nocturnal hemoglobinuria, myelodysplastic syndromes and primary myelofibrosis, and included diagnostic criteria and severity classification as well as clinical pictures derived from nationwide survey studies. Therapeutic measures were evaluated according to the concepts of evidence-based medicine, when applicable. This report presents an overview of these guides and summarizes key issues in each disease entity.

Underlying diseases, complications, clinical findings, and laboratory findings were evaluated in 158 cases of septicaemia admitted to Jikei University Hospital from 1975 to 1994, in order to conjectured factors that prescribe for the prognosis. 50% of the patients had underlying diseases. Malignancy including leukaemia (31 cases, 39.2%) was the most common underlying disease, followed by low birth weight infant (17 cases, 21.5%), aplastic anemia (9 case, 11.4%), and congenital heart disease (7 cases, 8.9%). The death rate for patients with underlying disease (27.8%) was significantly greater than the mortality for normal patients with septicaemia (8.9%) (p < 0.05). Meningitis (24.7%) was the most common complication, followed by DIC (19.6%), shock (15.2%), and pneumonia (10.8%). The mortality rate of septicaemia complicated by shock was 66.7% (p < 0.01), and that complicated by DIC was 45.2% (p < 0.01). The mortality rate for patients with the clinical findings of respiratory distress, cough, abdominal distention, cyanosis, splenomegaly, or peripheral coldness was more than 40% and significantly greater (p < 0.01). Mortality rate in patients with granulocyte counts of < 4.000/mm3, platelet counts of < 5 x 10(4)/ mm3, total protein of < 5.0 g/dl, or ESR of < 20 mm/hr were significantly greater (p < 0.01) than those in patients with normal laboratory findings. Coincidence rate of blood and stool cultures was 57.9% for E. coli, and 28.6% for Klebsiella sp., and that of blood and throat cultures was more than 30% for Pseudomonas sp., Haemophilus influenzae, and Staphylococcus aureus. In the study of antimicrobial susceptibility for microorganisms isolated, the number of drug resistant S. aureus had increased in the last 10 years.