Tetsuro Fujimoto

Nationwide Study of Idiopathic Thrombocytopenic Purpura in Pregnant Women and the Clinical Influence on Neonates

Idiopathic thrombocytopenic purpura (ITP) occurs more commonly in young women during the reproductive years. To obtain information for management of ITP in pregnancy, we performed a nationwide retrospective survey. Findings from a total of 284 pregnant women with ITP and their 286 newborn infants were available for analysis. The bleeding tendency at delivery was managed chiefly with corticosteroid, intravenous high-dose γulin, and platelet transfusion. Maternal complications occurred in 77 cases (27.1%) and were frequently seen in cases with poor control of ITP. Neonatal abnormalities, which were not influenced by the clinical state of the mother, occurred at a frequency of 17.8%. Thrombocytopenia in neonates occurred in 48 cases (22.4%), and bleeding tendency was found in 16 cases (6.3%) without severe bleeding. Prediction of thrombocytopenia in neonates was difficult. However, infants from splenectomized mothers with well-controlled ITP showed thrombocytopenia more frequently than those from nonsplenectomized mothers. Mothers treated with steroids at doses greater than 15 mg/day showed a high frequency of maternal complications and fetal abnormal body weight. These observations will be useful in the management of pregnant women with ITP and their infants.

Oligoclonal accumulation of T cells in peripheral blood from patients with idiopathic thrombocytopenic purpura

To determine whether clonal T cells accumulate in idiopathic thrombocytopenic purpura (ITP), we performed single‐strand conformation polymorphism (SSCP) analysis to detect T‐cell receptor (TCR) β‐chain usage of peripheral T cells. We detected significantly more oligoclonal T cells (15.5 ± 8.9 bands representative for clonal T‐cell expansions) in peripheral blood from ITP patients than from healthy donors (2.8 ± 2.6 bands). Frequently used Vβ genes in these accumulated T cells in ITP were Vβ 3, 6, 10, 13.1 and 14. To determine whether these bands were derived from clonal T cells, presumably in a preactivated state, we established some T‐cell clones (expressing CD4 and TCR Vβ 6, 13.1, or 14) by nonspecific stimulation from patients’ peripheral mononuclear cells, and examined their clonotypes. Clonal identities for three out of seven clones tested were confirmed using SSCP analyses to compare the migration of their β‐chain complementarity determining region 3 (CDR3) cDNAs, expanded by polymerase chain reaction (PCR) with those from peripheral blood. Therefore, distinctive T‐cell clones accumulated in the periphery in ITP and they may be related to the autoimmune‐mediated destruction of platelets.

Blastic transformation in essential thrombocythemia. In vitro differentiation of blast cells into granulocytic, erythroid, and megakaryocytic lineages.

A 57‐year‐old man with essential thrombocythemia (ET) developed myelofibrosis, that progressed to a blastic transformation state. The characteristics of the blastic cells were serially studied both morphologically and phenotypically as well as in cell culture. The blastic cells that were first detected in peripheral blood had features of myeloid stem cells with slight differentiation toward megakaryocytic lineage. However, later in the course, most of the blastic cells were immature. During culture in the presence of human plasma‐derived serum (PDS), some blastic cells obtained at the initial stage differentiated, mainly to both granulocytes and macrophages morphologically, but later tended to differentiate into both megakaryocytes and macrophages. Finally the blasts appeared to have lost their ability to differentiate morphologically. However, the blasts formed mixed colonies consisting of erythroblasts, granulocytes, macrophages, and immature blasts when cultured in methylcellulose with PHA‐leukocyte conditioned medium. In addition, the blastic cells in suspension culture strongly expressed phenotypic features which are characteristic of erythroblasts, in the presence of both PDS and 12‐0‐tetradecanoylphorbol 13‐acetate (TPA), whereas they expressed features of megakaryoblasts in the presence of PDS alone. These results suggest that essential thrombocythemia is of myeloid stem cell origin. This is the first case in the literature in which a clonal evolution in ET has been followed closely, essential events were identified serially, and the blastic cells, which appeared as a result of the progression of ET, were found to have the capability to differentiate toward the three myeloid lineages.

Abnormal Ca2+ homeostasis in platelets of patients with myeloproliferative disorders: low levels of Ca2+ influx and efflux across the plasma membrane and increased Ca2+ accumulation into the dense tubular system.

Ca2+ influx and efflux in unstimulated platelets and Ca2+ uptake by simultaneously isolated two membrane fractions of platelets from patients with myeloproliferative disorders (MPD) have been investigated. In MPD, Ca2+ influx and efflux across the plasma membrane in unstimulated platelets were in equilibrium at significantly lower levels than in normals. Ca2+ uptake by external membrane fraction isolated from MPD platelets was lower, whereas, uptake by internal membrane fraction enriched with dense tubular system (DTS) from MPD platelets was significantly higher than that from normal platelets. This corresponded with the membrane associated Ca2+-activated ATPase activity. These abnormalities of calcium ion movement in plasma membrane and dense tubular system illustrates one of the mechanisms of qualitative abnormalities of MPD platelets.

Cloning and Characterization of the Gene Encoding the Murine Glycoprotein V: The Conserved Thrombin-Cleavable Protein on Platelet Surface

Glycoprotein V (GPV) is a platelet membrane protein present as a subunit of the GPIb/V/IX complex, a major receptor for von Willebrand factor, and is specifically cleaved by thrombin. In this study, we have cloned and characterized murine GPV gene. The entire coding sequence of murine GPV consisted of 1704 nucleotides and coded 567 amino acids, which were 70% identical with human GPV. Fifteen leucine-rich tandem repeats were present and the consensus sequence of the repeats was completely matched with that of human GPV. The thrombin-cleavage site was also conserved exactly at the same position. In Northern blot, murine GPV mRNA was specifically expressed in murine platelets, bone marrow cells and megakaryocytic cell lines. In the survey of other organs, GPV was not expressed at all. These results demonstrate that GPV is highly conserved, thrombin-cleavable protein beyond the species, and is a specific protein in the platelet-megakaryocyte lineage.

IgA-λ Type Russell Bodies in Malignant Lymphoma of the Stomach

A case of primary malignant lymphoma of the stomach is reported. A 66-year-old man had an abdominal operation for subtotal gastrectomy due to massive bleeding from a stomach tumor.Under light microscopy, the tumor was identified to be a diffuse large cell lymphoma, large non-cleaved, according to the Working Formulation. It was quite unusual that also there were numerous cells which exhibited Russell bodies, among the typical large non-cleaved ones.Some of these cells with Russell bodies, had the same atypical nuclei as lymphoma cells, and these Russell bodies were positive for PAS stain. By the immunohistochemical analysis (ABC method) for IgA, λ and J chains, Russell bodies stained strongly positive and some of the lymphoma cells were also positive though in a spotty form, but for IgG, IgM and κ chains, all stained negative.These results indicate that those cells with Russell bodies, which did not appear as of the reactive component, had monoclonality and that some cells within, originated from lymphoma cells and produced IgA-λ type immunoglobulin which led to the formation of Russell bodies. Clinically, the patient was induced to a complete remission state by the combination chemotherapy of VEPA (vincristine, endoxan, prednisolone, adriamycin), and he has been maintaining the complete remission for two years now.