A lower starting dose of eltrombopag is efficacious in Japanese patients with previously treated chronic immune thrombocytopenia.

BACKGROUND: Eltrombopag is an oral, non-peptide thrombopoietin receptor agonist that has shown efficacy and safety in chronic immune thrombocytopenia (ITP). However, ethnic differences in eltrombopag exposure have been reported: area under the curve exposure to eltrombopag was 87% greater among ITP patients of East Asian descent than among ITP patients of non-East Asian ITP descent. OBJECTIVES: To evaluate the efficacy and safety of eltrombopag by using, in Japanese ITP patients, lower starting (12.5 mg) and maximum (50 mg) doses of eltrombopag than the standard starting (50 mg) and maximum (75 mg) doses approved in the USA and Europe. PATIENTS: We examined 23 Japanese patients with previously treated chronic ITP with a platelet count of < 30,000 µL(-1) in a multicenter study comprising a randomized, double-blind, placebo-controlled phase for 6-week evaluation (15 eltrombopag, and eight placebo) and an open-label phase for 6-month evaluation (23 eltrombopag). RESULTS AND CONCLUSIONS: The response rate (platelet count of ≥ 50,000 µL(-1) ) at week 6 of the 6-week double-blind phase was 60% in eltrombopag-treated patients and 0% in placebo-treated patients. Ten of 23 patients (43.5%) responded for ≥ 75% of predefined assessment visits during the 6-month open-label phase. Notably, 22% (5/23) of patients responded to 12.5 mg of eltrombopag, which was administered within the first 3 weeks of eltrombopag treatment. Bleeding decreased with eltrombopag treatment as compared with baseline. Eltrombopag was generally well tolerated; one patient experienced a transient ischemic attack on day 9. Eltrombopag (12.5-50 mg) is effective for the management of Japanese patients with chronic ITP (NCT00540423).

New approaches for antithrombotic antiplatelet therapies.

Cardiovascular diseases are one of the major causes of mortality in the western world. As platelet dependent thrombosis is of central importance in their pathophysiology, several successful strategies, targeting a specific platelet function or interaction, have been developed to prevent or treat these disorders. However, as the current antiplatelet strategies are limited in efficacy and safety, and often influence normal haemostatic functions, new compounds are being developed with improved characteristics. This review deals with the development of novel antiplatelet compounds for which evidence is available on their antithrombotic action in vivo. In a first part, these compounds, their targets and their potential applicability are discussed. The second part of this review focuses on BT tests and bleeding models and their usefulness for determination and/or prediction of the safety of novel antiplatelet compounds.

Lack of allelic exclusion and isotype switching in B cell chronic lymphocytic leukemia.

Two rearranged bands of the IgH gene were detected in a case with B cell chronic lymphocytic leukemia (B-CLL). The expressed VH gene was only VH1 with no somatic mutations in IgM and IgD. The expressions of C mu, C delta, and C gamma were detected by reverse transcription of RNA followed by the polymerase chain reaction (RT-PCR). Sequence analysis of the CDR3 regions of each PCR reaction product showed that the sequence of one rearranged allele was identical to those of the expressed VH1 gene, C mu and C delta, and the sequence of another rearranged allele was identical to that of C gamma. However, none of the expressed VH genes was detected in IgG. These findings suggest that this is a case of B-CLL lacking allelic exclusion and undergoing a class switch of one allele with the incomplete expression of the VH gene.

Hemodialysis together with peritoneal dialysis is one of the simplest ways to maintain adequacy in continuous ambulatory peritoneal dialysis.

When long-term peritoneal dialysis (PD) is performed without change in the dialysis prescription, uremic symptoms appear owing to insufficient dialysis dose. In such cases, an increase in dialysate volume is required, but this increase is difficult to obtain in all patients owing to limitations in abdominal volume, lifestyle, or body weight. A combination of PD and hemodialysis (HD) is the simplest method of overcoming these limitations. Combination therapy--HD once per week for 4 hours and PD 6 days per week--was performed in our patients. The total weekly dialysis dose (urea) was calculated as follows: to convert the dialysis dose by HD to that of continuous treatment, the equivalent renal urea clearance (EKR) was calculated and added to the dialysis dose by PD. Combination therapy was performed in 12 patients. The reasons for the combination therapy included ultrafiltration (UF) loss in 2 patients, uremic symptoms in 3 patients, poor fluid management in 5 patients, umbilical hernia in 1 patient, and hydrothorax in 1 patient. Total Kt/V per week was increased from 1.61 +/- 0.19 to 2.05 +/- 0.25 in these patients. In the 2 patients with UF loss, weight control became easier after the combination therapy was started, and this control was possible with hypotonic dialysate alone. In patients with uremic symptoms, the symptoms improved; furthermore, dermal pigmentation improved in these patients. In summary, the dialysis dose was increased and body fluids became controllable after inducing combination therapy, resulting in improvement uremic symptoms and increased quality of life.

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.

[Acquired pure red cell aplasia associated with relapsed non-Hodgkin's lymphoma: a case report-improvement of PRCA after acute hepatitis].

A 47-year-old male patient was admitted because of anemia. He had been diagnosed as non-Hodgkin's lymphoma (Follicular mixed, B cell type, stage ISA) by splenectomy two years before. Bone marrow examination on admission revealed lymphoma cell infiltration and marked decrease in erythroid cells. These findings confirmed relapsed lymphoma with acquired pure red cell aplasia. After several courses of combination chemotherapy, lymphoma cells disappeared from bone marrow, but PRCA was not improved. In this case there were two times remission of PRCA. At first time, acute B type hepatitis occurred during the chemotherapy, anemia improved transiently. At the second time, mild acute hepatitis associated with herpes zoster occurred. Twenty days after hepatic injury, PRCA was improved, and continued in remission state till present day. To disclose the mechanism of PRCA in this case, erythroid colony assay of marrow cells was performed. This showed the presence of inhibitory factor in patient's serum at PRCA state, that was considered to be related to the occurrence of PRCA. These findings suggest that the improvement of PRCA was associated with the changes on immunological condition after acute hepatitis in this case.

A point mutation in glycoprotein IX coding sequence (Cys73 (TGT) to Tyr(TAT)) causes impaired surface expression of GPIb/IX/V complex in two families with Bernard-Soulier syndrome.

Bernard-Soulier syndrome (BSS) is a rare inherited bleeding disorder which is caused by abnormal expression or function of the glycoprotein (GP) Ib/IX/V complex, a platelet major receptor for von Willebrand factor. We studied four BSS patients in two unrelated families in which the same and novel mutation was found. Flow cytometric analysis showed that GPIX was completely absent but residual amounts of GPIb alpha and GPV were detectable in these patients. We analyzed all coding regions of GPIb alpha, GPIb beta, GPV and GPIX which were amplified from the patients' genomic DNA by the polymerase chain reaction (PCR). In all four cases, we identified a point mutation in the GPIX coding region that changes the codon for cysteine 73 (TGT) to a codon for tyrosine (TAT). Furthermore, we confirmed by a transient expression study that the mutation caused the loss of adequate surface expression of GPIX. Since cysteine might be important for the secondary structure, this mutation of GPIX gene would lead to a dramatic conformational change of GPIX protein, resulting in the reduced surface expression. We concluded that this novel point mutation of the GPIX gene was responsible for BSS in these families.

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) beta-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 V beta genes in these accumulated T cells in ITP were V beta 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 V beta 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 beta-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.