Takeki Mitsui

Interleukin-17F gene polymorphism in patients with chronic immune thrombocytopenia

Introduction:  IL‐17F is a novel inflammatory cytokine and plays an important role in some autoimmune diseases. We investigated the association between chronic ITP and the frequency of the single‐nucleotide polymorphism rs763780 (7488T/C), which causes a His‐to‐Arg substitution at amino acid 161.

Circulating plasmacytoid dendritic cells in patients with primary and Helicobacter pylori-associated immune thrombocytopenia.

Objectives:  Immune thrombocytopenia (ITP) is an autoimmune disorder characterized by the production of autoreactive antibodies against platelet antigens. Although dysfunction of multiple aspects of cellular immunity is considered to be important in the pathogenesis of ITP, it has not been clarified which cell types play a principal role.

Interleukin-10 gene polymorphism reflects the severity of chronic immune thrombocytopenia in Japanese patients

Introduction:  T‐helper cell type 1 (Th1) polarization of the immune response has been documented in patients with chronic immune thrombocytopenia (ITP). Interleukin (IL)‐10 is the most important factor regulating Th1 and T‐helper type 2 cytokine synthesis. This study evaluated the impact of IL‐10 polymorphisms on both susceptibility to, and severity of, chronic ITP.

Successful Treatment of Autoimmune Hemolytic Anemia Associated with Multicentric Castleman Disease by Anti-Interleukin-6 Receptor Antibody (Tocilizumab) Therapy

We describe herein the successful treatment of severe autoimmune hemolytic anemia (AIHA) in a patient with multicentric Castleman disease (MCD) by humanized anti-interleukin-6 (IL-6) receptor antibody (tocilizumab) therapy. Inflammatory anemia is commonly reported; however, AIHA is a very rare complication of MCD. In 1996, a 45-year-old Japanese woman was referred to our hospital because of generalized lymphadenopathy, anemia and skin eruptions. Lymph node biopsy demonstrated MCD. She was treated with prednisolone (1 mg/kg/day), which improved the anemia and skin eruptions. In 2009, she suddenly developed Coombs-positive hemolytic anemia. The blood count was as follows: hemoglobin 4.7 g/dl, platelets 490 × 109/l and white blood cell count 9.8 × 109/l. Both direct and indirect Coombs’ tests were strongly positive. She was treated with 8 mg/kg tocilizumab every 2 weeks. One month later, her hemoglobin levels rose dramatically to 10.9 g/dl and her haptoglobin level, hypergammaglobulinemia and clinical symptoms had also markedly improved. To the best of our knowledge, this is the first report of the efficacy of tocilizumab in AIHA associated with MCD. The well-established role of IL-6 in the pathogenesis of MCD may have been responsible for the improvement in the AIHA associated with MCD. Anti-IL-6 receptor antibody treatment could be an attractive therapeutic approach for AIHA associated with MCD.

Characteristic expansion of CD45RA+ CD27− CD28− CCR7− lymphocytes with stable natural killer (NK) receptor expression in NK‐ and T‐cell type lymphoproliferative disease of granular lymphocytes

We analysed the cell surface expression of chemokine receptors and natural killer receptors (NKRs) in addition to conventional T‐ and natural killer (NK)‐cell markers in patients with lymphoproliferative disease of granular lymphocytes (LDGL), and compared results between NK‐ and T‐LDGL subgroups. The subjects of this study were 15 LDGL patients: four NK‐LDGL and 11 T‐LDGL [six CD8+ T‐cell receptor (TCR) αβ+, four CD4+ TCRαβ+ and one CD8+ TCRγδ+] cases. Flow cytometric analysis showed that the expanding cells had a common phenotype, CD45RA+ CD27− CD28− CCR7−, in NK‐ and T‐LDGL patients irrespective of differences in TCR status. There were no marked differences in the expression patterns of chemokine receptors between NK‐ and T‐LDGL patients. Although restricted NKR subsets were expressed on both NK‐ and T‐large granular lymphocytes (LGLs), CD94 was the most widely expressed marker. These findings may be unique to cells of LDGL cases, because normal CD56dim NK cells frequently express killer cell immunoglobulin‐like receptors. Furthermore, analysis of NKR expression was repeated over an interval of more than 6 months, and fluctuations of NKR repertoire in the LGL clones were minimal.

TCR Vβ repertoire analysis in CD56+ CD16dim/− T-cell large granular lymphocyte leukaemia: association with CD4 single and CD4/CD8 double positive phenotypes

Summary.  We report 10 patients with T‐cell large granular lymphocyte (LGL) leukaemia: four patients had CD16+ CD56− LGL lymphocytes (typical for LGL leukaemia), and six patients had CD56+ CD16dim/− LGL lymphocytes (atypical). Among the CD56+ CD16dim/− patients, LGL lymphocytes were CD4+ CD8− in one patient, CD4/CD8 double positive (DP) in three, and CD4− CD8+ in two. The CD4+ CD8dim DP cells expressed a CD8αα homodimer. T‐cell receptor (TCR) Vβ complementarity‐determining region 3 (CDR3) size distribution analysis and direct sequencing identified at least 1 in‐frame clonal TCR Vβ transcript in each patient; three patients had two or three different clonal sequences. To determine whether these transcripts were translated into cell surface TCR, we performed flow cytometric analysis using Vβ monoclonal antibodies (mAbs). A single Vβ protein was identified in patients, even those with multiple in‐frame transcripts. Previous and present results suggest that CD56+ CD16dim/− LGL leukaemia is more common than previously thought, and is associated with unusual phenotypes. When assessed using only molecular techniques, the monoclonal status of this disease may be misinterpreted as oligoclonal; thus, flow cytometric analysis using Vβ mAb is quite useful. Because mAbs do not cover the entire Vβ repertoire, assessing clonality using a combination of molecular methods and mAbs is preferable.

X-linked agammaglobulinemia diagnosed in adulthood: a case report.

X-linked agammaglobulinemia (XLA) is a humoral immunodeficiency caused by mutations in Bruton’s tyrosine kinase (BTK). Patients typically become symptomatic during infancy or early childhood and develop recurrent bacterial infections. We report a Japanese case of XLA diagnosed in a patient who was 27 years of age and who had no history of severe infection. The patient’s serum immunoglobulin (Ig) G, IgA, and IgM levels were 132, 7, and 17 mg/dL, respectively. The percentage of positive cells for CD19 and CD20 was 0.03% and 0.02%, respectively. The patient’s brother and sister had no abnormalities. Flow cytometric analysis showed a partially reduced expression of BTK protein in the patient’s peripheral monocytes. Sequencing of the BTK gene revealed a missense mutation (230C>T,T33I). Given this data, this patient was diagnosed as having rare, late onset XLA with a missense mutation in the BTK gene.

A new staging system to predict prognosis of patients with multiple myeloma in an era of novel therapeutic agents

Various prognostic markers for multiple myeloma (MM) have been identified, and stratification using these markers is considered important to optimize treatment strategies. The international staging system (ISS) is now a widely accepted prognostic staging system for MM patients; however, its validity is controversial in the era of new therapeutic regimens, since ISS had been established before introduction of new agents. We retrospectively reviewed prognostic factors in order to seek out an alternative staging system more suitably applied to MM patients treated with novel agents. We analyzed 178 newly diagnosed MM patients who received either conventional chemotherapy without novel agents (CT; n = 79) or chemotherapy with novel agents (NT; n = 99). Although median overall survival (OS) of patients treated with CT is significantly different depending on stages of ISS, ISS had no effect on OS among patients treated with NT. Meanwhile, we identified hemoglobin (Hb) and plasmacytoma as independent risk factors for OS in patients who received NT. Using these two parameters, we stratified NT patients into three stages; stage 1 (Hb≥10 g/dL and absence of plasmacytoma), stage 2 (not stage 1 or 3), and stage 3 (Hb <10 g/dL and presence of plasmacytoma). We found that there were significant differences in median OS among the three stages (8.13, 5.95, and 2.45 yr for stages 1, 2, and 3, respectively). This preliminary study suggests that this alternative staging system based on Hb and plasmacytoma is a simple and useful way to predict prognosis of MM patients in the novel agent era.

Characterization of CD56+ dendritic-like cells: a normal counterpart of blastic plasmacytoid dendritic cell neoplasm?

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematological malignancy. Plasmacytoid DCs (pDCs), which are defined as lineage marker (Lin)−HLA−DR+CD56−CD123+CD11c− cells, are considered to be the normal counterpart of BPDCNs. However, BPDCN can be distinguished from pDCs by uniform expression of CD56. In this study, to identify a normal counterpart of BPDCN, we searched for a Lin−HLA−DR+CD56+ population and focused on a minor subpopulation of Lin−DR+CD56+CD123+CD11c− cells that we designated as pDC-like cells (pDLCs). pDLC constituted 0.03% of peripheral blood mononuclear cells (PBMCs), and the pDLC/pDC ratio was higher in bone marrow cells than in PBMCs. pDLC clearly expressed BDCA2, BDCA4, and myeloid antigens, which are frequently expressed by BPDCN. pDLCs exhibited modest expression of Toll-like receptors and produced less interferon-α after CpG stimulation, but presented very low endocytic ability unlike mDCs. These functional differences were attributed to the expression profile of transcriptional factors. After in vitro culture with Flt3-ligand and GM-CSF, pDLCs expressed CD11c and BDCA1. These data suggested that pDLCs are a distinct subpopulation, with an immunophenotype similar to BPDCNs. Moreover, our results indicate that pDLCs might be immature DCs and might contribute to the immunophenotypical diversity of BPDCNs.

Gene polymorphisms of mannose-binding lectin confer susceptibility to Pneumocystis pneumonia in HIV-infected patients.

BACKGROUND Mannose-binding lectin (MBL) plays an important role in innate immunity. The aim of this study was to determine whether genetic variants of MBL confer susceptibility to Pneumocystis pneumonia (PCP) in patients with advanced human immunodeficiency virus (HIV) infections. OBJECTIVE HIV patients (n = 53) having CD4 counts <200/μL who were admitted to our hospital were analyzed. Of these 53 patients, 30 had PCP at admission, and 23 did not. Genotypes at six single nucleotide polymorphisms (SNP) in MBL2 gene and serum MBL levels were determined for each patient, and compared between patients with or without PCP. We also examined whether MBL enhances phagocytosis of macrophages against rat-type Pneumocystis organism in vitro. RESULTS Genotypes associated with low production of MBL were significantly more common in the PCP group than in the non-PCP group (P = 0.049, odds ratio 2.17, 95% CI 1.02-4.63). Serum MBL levels were significantly higher in the non-PCP group (P = 0.039). Findings from in vitro experiments indicated that MBL act as a direct opsonin enhancing macrophage-mediated phagocytosis of Pneumocystis organisms. CONCLUSION Genetic variation of MBL production influences susceptibility to PCP in patients with advanced HIV infection, and can be regarded as a risk factor for PCP.