Refractory immune thrombocytopenic purpura associated with IgM monoclonal gammopathy of undetermined significance: Successful treatment with tirabrutinib plus conventional therapies

When immune thrombocytopenia (ITP) is secondary to malignant diseases, chemotherapy is expected to improve the platelet count (PC) as well. Herein, we report a case of a 72‐year‐old man with ITP refractory to standard therapies. IgM monoclonal gammopathy of undetermined significance (MGUS) was determined as an underlying disease. After bendamustine and rituximab (BR) therapy was found inadequately effective, tirabrutinib, a novel Bruton's tyrosine kinase inhibitor, was initiated, and the PC normalised subsequently. Surveillance of underlying diseases with which effective therapies are available may help manage refractory ITP, and IgM‐MGUS is potentially a targetable underlying disease with this newly available drug.

[Acquired hemophilia A with high-titer factor VIII inhibitor developing subsequent to clopidogrel administration]

An 80-year-old male was referred to our department for prolonged APTT (activated partial thromboplastin time) and subcutaneous hemorrhage. His medical history comprised alcoholic liver cirrhosis, hepatocellular carcinoma (HCC), and peripheral artery disease (PAD). For refractory HCC, he had received transcatheter arterial chemoembolization and was followed up regularly at our hospital. He underwent percutaneous transluminal angioplasty for PAD 10 months ago, and dual antiplatelet therapy with clopidogrel and cilostazol was initiated. Cilostazol was discontinued owing to subcutaneous hemorrhage 6 months ago. The prolonged APTT level, inhibitor pattern by cross-mixing test, and the presence of the inhibitor against factor VIII (449 Bethesda unit/ml) corroborated acquired hemophilia A (AHA). Thus, clopidogrel was discontinued for possible drug-induced AHA. After 4-week oral corticosteroid therapy, the APTT level recovered to normal. This case highlights two distinct features as follows: (1) possible relation to clopidogrel; and (2) despite extremely high titer of factor VIII inhibitor, his bleeding episodes were managed without antihemorrhagic agents. Here we present a case of clopidogrel-related AHA. Further accumulation of such cases is warranted to determine the potential correlation with clopidogrel and AHA.

[Autologous peripheral blood stem cell transplantation for treating primary central nervous system lymphoma: a single-center retrospective study]

Primary central nervous system lymphoma (PCNSL) is more difficult to treat than other lymphomas. Recently, it has been suggested that high-dose chemotherapy followed by autologous stem cell transplantation (ASCT) is effective for treating PCNSL. In the present study, we retrospectively analyzed 12 patients with PCNSL at our hospital. Five young patients with good performance status (PS) received upfront ASCT. The conditioning regimen prior to ASCT with busulfan ＋ cyclophosphamide ＋ etoposide showed good prognosis (complete remission rate of 100%). In addition, the PS improved in patients treated with high-dose chemotherapy followed by ASCT, while it worsened in those treated without ASCT. Further investigations are needed to clarify inclusion/exclusion criteria and optimize conditioning regimens for ASCT.

Rapidly progressive autoimmune pancytopenia successfully treated with steroids

A 73-year-old woman was admitted to our hospital because of pancytopenia. Bone marrow aspiration showed increased cellularity with no dysplastic change. Laboratory tests revealed increased reticulated erythrocytes and reticulated platelets, positive direct Coombs test, and hemolysis. These findings led to the diagnosis of Evans syndrome. Relatively decreased mature neutrophils in the bone marrow aspirate raised the possibility of autoimmune neutropenia. Antineutrophil antibody was detected by the 6 cell-lineage immunofluorescence test, consistent with the diagnosis of autoimmune neutropenia. The patient had no underlying diseases, and was therefore considered to have idiopathic autoimmune pancytopenia. Due to rapid progression of the disease, prednisolone was administered at an initial dose of 0.5 mg/kg per day and the pancytopenia improved promptly.

Successful Treatment of TAFRO Syndrome, a Variant of Multicentric Castleman's Disease, with Cyclosporine A: Possible Pathogenetic Contribution of Interleukin-2

Multicentric Castleman's disease is a systemic inflammatory disorder characterized by lymphadenopathy and excessive interleukin-6 production. A unique clinicopathologic variant of multicentric Castleman's disease, TAFRO (i.e., thrombocytopenia, anasarca, fever, renal failure or reticulin fibrosis, and organomegaly) syndrome, was recently proposed in Japan. Despite the successful use of anti-interleukin-6 therapy in some patients with TAFRO syndrome, not all patients achieve remission. The pathophysiological etiology of and suitable therapeutic strategies for this variant have not been established. Here, we present our experience of a unique case of TAFRO syndrome in a 78-year-old woman whose symptoms responded differently to several therapies. Tocilizumab, an anti-interleukin-6 receptor antibody, successfully induced remission of fever and lymphadenopathy. However, severe thrombocytopenia persisted and she developed anasarca, ascites, and pleural effusion shortly thereafter. Rituximab, an anti-CD20 antibody, and glucocorticoid therapy provided no symptom relief. In contrast, cyclosporine A, an immunosuppressive agent that blocks T cell function by inhibiting interleukin-2, yielded immediate improvements in systemic fluid retention and a gradual increase in platelet count, with complete resolution of disease symptoms. Excessive serum interleukin-2, when used as an anti-cancer agent, has been reported to cause side effects such as fluid retention, thrombocytopenia, and renal failure. Our case was unique because the anti-interleukin-2 therapy successfully improved symptoms that were not relieved with anti-interleukin-6 therapy. The present report therefore provides insight into the possible role of interleukin-2, in addition to interleukin-6, in TAFRO syndrome. This report will certainly help to clarify the pathogenesis of and optimal treatment strategies for TAFRO syndrome.

Risk factors for and prognosis of hemorrhagic cystitis after allogeneic stem cell transplantation: retrospective analysis in a single institution

Hemorrhagic cystitis (HC) is a major complication after allogeneic stem cell transplantation (allo-SCT) and can be life threatening. To analyze risk factors and prognosis, we retrospectively reviewed 249 cases receiving allo-SCT in our institution. Median age was 47 years (13-72 years). Disease status at SCT was progressive in 73 cases. Conditioning was myeloablative (MAC) in 146 cases. Acute graft-versus-host disease (aGVHD) grade II-IV treated with prednisolone occurred in 82 cases, and cytomegalovirus (CMV) was reactivated in 91 cases. HC was reported in 47 cases at a median of 35 days (7-469 days) after SCT, and 34 (72.3%) cases recovered after a median of 19.5 days (2-252 days). In univariate analysis, the identified risk factors for HC included age over 45 years, progressive disease status, MAC, aGVHD treated with prednisolone, and CMV reactivation. In multivariate analysis, older age, MAC, and CMV remained independent predictors (hazard ratios: 2.35, 3.50, and 2.87). In patients with severe HC, percentage recovery was lower (3 in 13 cases; 23.1%) and the median duration was longer (54 days) than in those with moderate HC (31 in 36 cases; 86.1%, 17 days, P < 0.01). Treatment-related mortality was also higher (59.1%, P = 0.03) and overall survival was poorer (16.7%, P < 0.01) at 1 year after SCT. Prospective studies should be started considering prophylactic antiviral administration in high-risk patients such as those identified in this study.

Effects of the Tyrosine Kinase Inhibitor Imatinib Mesylate on a Bcr-Abl-Positive Cell Line: Suppression of Autonomous Cell Growth but No Effect on Decreased Adhesive Property and Morphological Changes

Expression of the Bcr-Abl oncoprotein alters various aspects of hematopoietic cells. We investigated the effects of a Bcr-Abl tyrosine kinase inhibitor, imatinib mesylate, on the proliferation, adhesive properties, and morphology of a Bcr-Abl-transferred cell line, TF-1 Bcr-Abl, in comparison with parental TF-1. First, the factor-independent growth of TF-1 Bcr-Abl was inhibited in the presence of imatinib mesylate, but this inhibition was overcome by addition of exogenous granulocyte-macrophage colony-stimulating factor. Imatinib mesylate remarkably reduced tyrosine phosphorylation of Bcr-Abl, Cbl, and Crkl in a time-dependent manner, and their complex formation also was affected. Imatinib mesylate inhibited activation of Stat5 rather than the MEK-ERK1/2 pathway. TF-1 Bcr-Abl cells exhibited a round shape, unlike TF-1, and the adhesive property to fibronectin was much lower than that of TF-1. Although the Bcr-Abl oncoprotein may be involved negatively in cell adhesion, the decreased adhesion and altered morphology of TF-1 Bcr-Abl cells were minimally affected by imatinib mesylate and seemed independent of Bcr-Abl kinase activity. The present data indicated that the Bcr-Abl-specific kinase inhibitor cannot control Bcr-Abl-induced cell alterations other than autonomous growth.

Successful treatment with paclitaxel of advanced AIDS-associated Kaposi's sarcoma

Kaposi's sarcoma (KS) is the most prevalent AIDS-associated tumor. We report a 44-year-old Japanese man with advanced AIDS-associated KS, which was spread over bilateral pulmonary parenchyma. He was initially treated with combination chemotherapy with a partial response. Upon the recurrence of his KS two months after the completion of the combination chemotherapy, the patient received paclitaxel, which brought about a complete response. Highly active antiretrovial therapy (HAART) was initiated three months before the combination chemotherapy, and the CD4+ T-cell count had risen before starting paclitaxel. His dinical course suggests that paclitaxel was highly effective for KS disease control as previously reported, and that immune restoration with HAART is crucial in the treatment of KS.

Sustained activation of MEK1-ERK1/2 pathway in membrane skeleton occurs dependently on cell adhesion in megakaryocytic differentiation

A human megakaryoblastic cell line, CMK, was treated with 12-o-tetradecanoylphorbol-13-acetate (TPA) for differentiation-induction. We examined TPA-induced activation of the MEK1-ERK1/2 pathway in the 100,000g Triton X-insoluble fraction of CMK cells as the membrane skeleton and researched the relation of the MEK1-ERK1/2 activation with integrin expression. We found that this activation was divided into two phases: the first activation occurred transiently in the membrane skeleton fraction of the suspended cell status and diminished after 1h; and the second sustained activation was maintained by cell adhesion. TPA-treated CMK cells revealed increased expression of integrins alphaIIb and beta3 only when the cell adhesion persisted, regardless of the difference of culture substratum. Sustained activation of the MEK1-ERK1/2 pathway is generated in the membrane skeleton by continuous cell adhesion and seems to be essential to TPA-induced megakaryocytic differentiation of CMK cells.

Adhesion via CD43 induces Syk activation and cell proliferation in TF-1 cells

The effect of adhesion via CD43 (leukosialin, sialophorin) on cell proliferation and phosphorylation signaling were examined in a growth factor-dependent hematopoietic progenitor cell line, TF-1. TF-1 cells promptly resulted in death after withdrawal of growth factors. However, the viable cell number increased when TF-1 cells were cultured on anti-CD43 monoclonal antibody-coated plates. In this case, sustained activation of protein tyrosine kinase Syk and extracellular signal-regulated kinase (Erk) 1/2 were detected. Overexpression of exogenous Syk on TF-1 cells by the adenovirus vector system induced enhancement of the cell proliferation accompanied with enhancement of the Erk activation by a dominant-positive effect. The signal transducer and activator of transcription (STAT) 5 seemed not to be associated with the CD43-mediated cell proliferation. These results indicated that adhesion via CD43 induces the proliferation of TF-1 cells in the absence of growth factors in part by Syk-dependent Erk 1/2 signaling.