Daiki Shimomura

A novel role for Notch ligand Delta-1 as a regulator of human Langerhans cell development from blood monocytes.

Human Langerhans cells (LCs) are of hematopoietic origin, but cytokine regulation of their development is not fully understood. Notch ligand Delta‐1 is expressed in a proportion of the skin. Granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) and transforming growth factor‐β1 (TGF‐β1) are also secreted in the skin. We report here that Delta‐1, in concert with GM‐CSF and TGF‐β1, induces the differentiation of human CD14+ blood monocytes into cells that express LC markers: CD1a, Langerin, cutaneous lymphocyte‐associated antigen, CC chemokine receptor 6, E‐cadherin, and Birbeck granules. The resulting cells display phagocytic activity and chemotaxis to macrophage inflammatory protein‐1α (MIP‐1α). In response to CD40 ligand and tumor necrosis factor α, the cells acquire a mature phenotype of dendritic cells that is characterized by up‐regulation of human leukocyte antigen (HLA)‐ABC, HLA‐DR, CD80, CD86, CD40, and CD54 and appearance of CD83. These cells in turn show chemotaxis toward MIP‐1β and elicit activation of CD8+ T cells and T helper cell type 1 polarization of CD4+ T cells. Thus, blood monocytes can give rise to LCs upon exposure to the skin cytokine environment consisting of Delta‐1, GM‐CSF, and TGF‐β1, which may be, in part, relevant to the development of human epidermal LCs. Our results extend the functional scope of Notch ligand δ‐1 in human hematopoiesis.

Relationship between plasma dabigatran concentration and activated partial thromboplastin time in Japanese patients with non-valvular atrial fibrillation

Activated partial thromboplastin time (aPTT) is recommended for monitoring anticoagulant activity in dabigatran‐treated patients; however, there are limited data in Japanese patients. To clarify the relationship between plasma dabigatran concentration and aPTT, we analyzed plasma dabigatran concentration and aPTT at various time points following administration of oral dabigatran in a Japanese hospital.

The Influence of Assay Selection on Prothrombin Time Measured in Patients Treated With Rivaroxaban for Nonvalvular Atrial Fibrillation

Prothrombin time (PT) can provide a qualitative assessment of the relative intensity of anticoagulation by rivaroxaban. More than ten types of assay are available for the measurement of PT in clinical settings, but it is not yet fully understood whether their interactions with rivaroxaban are uniform or inconsistent.

Establishment and characterization of a novel Hodgkin lymphoma cell line, AM-HLH, carrying the Epstein-Barr virus genome integrated into the host chromosome.

We describe the establishment and characterization of a cell line, AM‐HLH, obtained from a patient with Epstein‐Barr virus–positive (EBV+) nodular sclerosis–type Hodgkin lymphoma (HL). The cells were positive for CD2 and CD30 and negative for CD15. The immunoglobulin heavy‐ and κ light–chain genes were rearranged. The karyotype was of the triploid range. Southern blotting using the EBV terminal repeat probe detected 3 hybridizing bands that were identical to those of the parental HL material. The cells expressed EBV‐encoded RNAs as well as latent genes (EBNA1, EBNA2, LMP1, and LMP2A) and lytic genes (BZLF1 and BALF2). Fluorescence in situ hybridization (FISH) with the cosmid pJB8 clone containing a fragment of EBV DNA as a probe revealed multiple hybridization signals at a marker chromosome. Additional FISH using whole chromosome painting and centromere probes in combination with multicolor FISH determined that multiple EBV copies were clustered within the chromosome 20 materials of the marker chromosome. Culture supernatants of AM‐HLH contained IL‐10 as measured by the bead‐based immunoassay. It is possible that an integrated EBV genome and cellular genes on chromosome 20 were coamplified, leading to the enhanced expression of genes involved in cell growth control. The AM‐HLH cell line will be useful to clarify the role of cytokines in the development of EBV+ HL.

Acute basophilic leukemia associated with the t(16;21)(p11;q22)/FUS-ERG fusion gene

We herein report a rare case of acute basophilic leukemia with t(16;21)(p11;q22) generating the FUS‐ERG fusion gene. The basophilic nature of leukemia blasts was demonstrated by cytomorphology, toluidine blue metachromasia, mature basophil‐associated antigen expression, and characteristic granules under electron microscopy. The molecular link between t(16;21)/FUS‐ERG and basophilic differentiation remains unclear.

Delayed Development of Hemolytic Anemia with Fragmented Red Blood Cells and Cardiac and Renal Impairments after High-Dose Chemotherapy and Autologous Hematopoietic Stem Cell Transplantation for Malignant Lymphoma

Among 42 consecutive patients with malignant lymphoma who underwent high-dose chemotherapy (HDC) followed by autologous hematopoietic stem cell transplantation (AHSCT), 5 developed hemolytic anemia with fragmented red blood cells (HA-FrRBCs) on days 87-125 (median 107) of AHSCT. Nadir Hb levels ranged between 5.0 and 6.4 g/dL with 2.2-5.6% FrRBCs. All patients developed grade ≥3 hypoxia and heart failure, and 4 developed grade ≥3 hypertension. The ejection fraction of the left ventricle assessed by echocardiography was significantly reduced in 3 patients. Peak creatinine levels were >4 times above the baseline and estimated glomerular filtration rates were reduced to <30 mL/min/1.73 m2. One patient received plasma exchange, while the remaining 4 responded to treatment with diuretics and cardiovascular agents. Hematological parameters normalized within a median duration of 91 days after the development of HA-FrRBCs. Renal and cardiac functions gradually improved, even though renal function did not return to the baseline. HA-FrRBCs associated with cardiac and renal impairments may represent a thrombotic microangiopathy syndrome and are a delayed complication of HDC/AHSCT. The close monitoring of laboratory abnormalities and persistent treatment with cardiovascular agents and diuretics are the mainstay for the management of this condition.

Long-term treatment course of a patient with mild haemophilia A who developed a high titre factor VIII inhibitor

The activity of coagulation factor VIII (FVIII:C) is reported to be between 5 and 40% in patients with mild haemophilia A (HA) 1. This disease is often diagnosed in adulthood due to bleeding episodes after trauma or surgery that require replacement therapy with FVIII concentrates (FVIIIc). Although FVIII inhibitors develop less frequently in mild HA patients than in those with severe HA, the development of inhibitors may become a major clinical problem because the inhibitor may inhibit both exogenous and endogenous FVIII, thereby converting the bleeding phenotype from mild to severe 1. We herein described the long-term treatment course of a patient with mild HA who developed a high titre FVIII inhibitor. The male patient was first diagnosed with mild HA at 76 years of age when he developed a postoperative bleeding complication following transurethral resection of bladder tumour (TUR-BT). A conventional coagulation test showed a prolonged activated partial thromboplastin time of 46.2 s (control value, 29.1 s), his FVIII:C was 11%, and no inhibitor was detected. During the subsequent 7 months, he safely underwent a second TUR-BT and coronary artery bypass graft surgery for myocardial infarction with the continuous infusion of FVIIIc (Confact F®). However, postoperative bleeding persisted in the bladder when he underwent a third TUR-BT for a refractory lesion, in spite of intensive replacement therapy with FVIIIc. FVIII:C decreased below 1% and the Bethesda assay revealed the development of an inhibitor, the level of peaked at 160 Bethesda units per millilitre (Fig.​(Fig.1).1). Frequent bleeding episodes were observed in the subcutaneous tissue, muscle and mucosa of the urogenital tract after the development of the inhibitor, which necessitated the repeated administration of the bypassing agent, recombinant activated factor VII (NovoSeven®; Novo Nordisc Ltd., Tokyo, Japan). He subsequently underwent reconstructive free-flap surgery following surgical removal of a subcutaneous haematoma associated with overlying skin necrosis of the dorsum of the left hand. Fig 1 Treatment course showing FVIII coagulant activity (FVIII:C) (%) and the inhibitor titre (Bethesda units per millilitre, BU mL−1). The treatment for bleeding consisted of replacement therapy with FVIII concentrates and the administration of recombinant ... We administered immunosuppressive treatment, which included prednisolone, oral cyclophosphamide and two cycles of rituximab (375 mg m−2 week−1 × 4 doses); however, even though its titre declined gradually, the inhibitor persisted for over 30 months (Fig.​(Fig.1).1). FVIII:C finally became detectable approximately 3 years after the inhibitor developed, and bleeding episodes no longer developed thereafter. We are notified that his grandson is treated for haemophilia at another medical centre; however, further information is unavailable. Genetic analysis of the F8 gene was performed after obtaining informed consent from the patient. An intron 22 inversion and intron 1 inversion were screened by long-distance polymerase chain reaction (PCR) and multiplex PCR, respectively. Twenty-six exons and their franking regions were amplified by PCR using specific primers and analysed by conformation-sensitive gel electrophoresis followed by nucleotide sequencing. This analysis revealed the deletion of four nucleotides on the 3′ splice site of intron 1 (c.144-11 TCTT del), a missense mutation, c.3780C>G; p.D1241E in the B-domain and a mutation, c.*1672A>G in the 3′ untranslated region of exon 26. In contrast to patients with severe HA with FVIII inhibitors, for whom immune tolerance induction (ITI) is indicated to restore responsiveness to FVIII, patients with mild HA who develop inhibitors have been shown to respond poorly to ITI 2. Therefore, immune suppression therapy to eradicate inhibitors should be considered in patients with bleeding patterns similar to acquired haemophilia, as with the present case. A search of the literature found case reports or small case series of the successful use of rituximab, an anti-CD20 antibody, alone or in combination with high-dose FVIII for mild HA with inhibitors 3–6. Franchini et al. summarized published cases and reported a high response rate to rituximab in patients with mild/moderate HA 6. However, when the relationship between the rituximab treatment and response obtained in the present case was assessed, the effect of rituximab appeared to be limited even though the inhibitor titre transiently declined after the first cycle of rituximab. It may be more likely that the inhibitor declined and disappeared spontaneously by avoiding the administration of FVIIIc. Molecular genetic studies of HA have identified a wide variety of mutations; a total of 2107 unique mutations, including 158 splice-site mutations, are listed in the Haemophilia A Mutation Database 7. The type of mutation in the F8 gene has generally been associated with not only the severity of HA, but also the risk of the formation of inhibitors 8. Large deletions, inversions and nonsense mutations are associated with severe HA and the highest risk of inhibitor development, while missense mutations have accounted for approximately 90% of reported cases of mild HA, in which inhibitor development was an uncommon complication 1,7,9. c.3780C>G; p.D1241E and c.*1672A>G, which were identified in the present case, are included in the list of polymorphic nucleotide substitutions detected in the F8 gene of both normal subjects and HA patients 7, even though previous studies have shown that p.D1241E is associated with lower FVIII:C and that p.D1241E-containing haplotypes contribute to the high incidence of inhibitors 8,10. On the other hand, c.144-11 TCTT del has not been registered in the database. This small deletion, which is located adjacent to the splice acceptor site of intron 1, may have affected structural and/or functional alterations in the F8 transcripts, thereby leading to the low FVIII:C observed in this case. Nevertheless, the mechanisms responsible for the development of inhibitors in patients with splicing mutations remain to be elucidated.