The Roles of ROS Generation in RANKL-Induced Osteoclastogenesis: Suppressive Effects of Febuxostat.

Receptor activator of NF-κB ligand (RANKL), a critical mediator of osteoclastogenesis, is upregulated in multiple myeloma (MM). The xanthine oxidase inhibitor febuxostat, clinically used for prevention of tumor lysis syndrome, has been demonstrated to effectively inhibit not only the generation of uric acid but also the formation of reactive oxygen species (ROS). ROS has been demonstrated to mediate RANKL-mediated osteoclastogenesis. In the present study, we therefore explored the role of cancer-treatment-induced ROS in RANKL-mediated osteoclastogenesis and the suppressive effects of febuxostat on ROS generation and osteoclastogenesis. RANKL dose-dependently induced ROS production in RAW264.7 preosteoclastic cells; however, febuxostat inhibited the RANKL-induced ROS production and osteoclast (OC) formation. Interestingly, doxorubicin (Dox) further enhanced RANKL-induced osteoclastogenesis through upregulation of ROS production, which was mostly abolished by addition of febuxostat. Febuxostat also inhibited osteoclastogenesis enhanced in cocultures of bone marrow cells with MM cells. Importantly, febuxostat rather suppressed MM cell viability and did not compromise Dox's anti-MM activity. In addition, febuxostat was able to alleviate pathological osteoclastic activity and bone loss in ovariectomized mice. Collectively, these results suggest that excessive ROS production by aberrant RANKL overexpression and/or anticancer treatment disadvantageously impacts bone, and that febuxostat can prevent the ROS-mediated osteoclastic bone damage.

PD-L1 upregulation in myeloma cells by panobinostat in combination with interferon-γ.

Immunotherapy is revolutionizing the treatment paradigm for multiple myeloma (MM). Interferon (IFN)-γ is essential for immune responses, whereas immune checkpoint molecules, such as programmed cell death-1 ligand-1 (PD-L1), mitigate the beneficial anti-tumor immune responses. As HDAC inhibitors alter the immunogenicity and anti-tumor immune responses, we here explored the regulation of PD-L1 expression in MM cells by the clinically available HDAC inhibitor panobinostat in the presence of IFN-γ. IFN-γ activated the STAT1-IRF1 pathway to upregulate PD-L1 expression in MM cells, and panobinostat was able to upregulate their PD-L1 expression without activating the STAT1-IRF1 pathway. Of note, panobinostat enhanced IFN-γR1 expression, which substantially increased the total and phosphorylated levels of STAT1 protein but reduced IRF1 protein levels through proteasomal degradation in the presence of IFN-γ. Panobinostat further enhanced the IFN-γ-mediated durable STAT1 activation in MM cells; STAT1 gene silencing abolished the PD-L1 upregulation by panobinostat and IFN-γ in combination, indicating a critical role for STAT1. These results suggest that panobinostat enhances PD-L1 expression by facilitating the IFN-γ-STAT1 pathway in a ligand-dependent manner in MM cells with ambient IFN-γ. PD-L1 upregulation should be taken into account when combining immunotherapies with panobinostat.

Cryptosporidiosis in a transplant recipient with severe intractable diarrhea: Detection of Cryptosporidium oocysts by intestinal biopsies.

Disseminated Cryptosporidium infection results in manifestations similar to those of graft-versus-host disease (GVHD), which hampers the detection of Cryptosporidium infection after allogeneic hematopoietic stem cell transplantation. Surveillance of oocysts on the surface of intestinal epithelial cells is needed for early and appropriate detection of Cryptosporidium infection in transplant recipients on immunosuppressants with severe intractable diarrhea. We present the first case of Cryptosporidium meleagridis infection in Japan after allogeneic cord blood transplantation.

[Analysis of long-term survivors with cardiac AL amyloidosis].

Cardiac AL amyloidosis (CA) is generally known as a severe disease with very poor prognosis. Here we retrospectively examined seven patients with CA in our cohort who achieved long-term survival. All six patients who underwent high-dose melphalan and autologous stem cell transplantation (ASCT) survived for >3 years, whereas four patients survived for >5 years. Patients who underwent ASCT had prompt hematological responses, and five patients showed organ responses. ASCT helps to achieve a quick and deep hematological response required for long-term survival in patients with CA. New agents have been implemented for the treatment of CA. However, the risks and benefits of each treatment modality should be considered according to patient condition, thus making the best use of ASCT in combination with new agents for the treatment of CA.

Memory B cell resurgence requires repeated rituximab in myasthenia gravis.

The immunologic effects of rituximab (RTX) in myasthenia gravis (MG) remain to be explored. We aimed to clarify immunologic reactions and their association with response to RTX in MG. Regulatory T cell and B cell profiles of MG patients were monitored. Two patients presenting with generalized MG with anti-acetylcholine receptor antibodies were treated with RTX. The treatment led to sustained clinical improvement, discontinuation of intravenous immunoglobulin or plasma exchange, and reduction of prednisolone and other drugs. One patient was in remission for more than one year, whereas the other patient exhibited deterioration of symptoms within one year. Disease activity was associated with the repopulation of IgD-CD27- and IgD-CD27+ memory B cells. Clinicians should be aware of the possibility that MG ranges in the duration of B cell depletion and additional RTX should be prescribed upon resurgence of memory B cells.

Hematopoietic neoplasms accompanied by severe enterocolitis due to Aeromonas species.

Aeromonas species are known to be a cause of diarrhea and acute enterocolitis. However, only a few cases have been reported and the pathophysiology of Aeromonas infection has not as yet been clarified. We experienced 2 cases developing severe enterocolitis during the course of hematological malignancies, specifically multiple myeloma and diffuse large B-cell lymphoma. Both patients presented with watery diarrhea that persisted for more than a week, followed by bloody diarrhea. Total colon endoscopy showed multiple ulcers on the mucosa from the sigmoid colon to the rectum, and biopsies from the ulcer revealed infiltration of neutrophils and eosinophils in the mucosa and submucosa. Aeromonas hydrophila and Aeromonas sobria were isolated from stool cultures, respectively. Treatment with oral ciprofloxacin was effective in both patients and clinical symptoms showed significant improvement. These cases raise the possibility of Aeromonas infection as a cause of severe enterocolitis and the importance of making a correct differential diagnosis and appropriate antibiotic treatment in immunocompromised patients including those with hematological malignancies.

[Azacitidine treatment for acute myeloid leukemia with myelodysplasia-related changes during peritoneal dialysis].

Azacitidine (AZA) is useful for the treatment of myelodysplastic syndrome; however, there are a few case reports involving patients receiving hemodialysis and no case reports involving patients receiving peritoneal dialysis. We describe a patient with acute myeloid leukemia with myelodysplasia-related changes (AML-MRC) receiving peritoneal dialysis who was treated with AZA. Peritoneal dialysis was initiated for an 85-year-old man with chronic renal failure in April 2014. In February 2015, peripheral blood analysis showed pancytopenia and bone marrow examination revealed excess of myeloblasts and dysplasia of trilineage cells. He was diagnosed with AML-MRC and treated with AZA because of being elderly and suffering from chronic renal failure. He achieved transfusion independence after 1 course and hematological remission after 3 courses of AZA treatment, without severe side effects. This case suggests that AZA is an effective therapeutic option for patients with AML-MRC receiving peritoneal dialysis.

Polymyositis as a paraneoplastic syndrome in cytotoxic molecule-positive and Epstein-Barr virus-associated peripheral T-cell lymphoma, not otherwise specified.

We encountered a rare case of cytotoxic molecule-positive and Epstein-Barr virus (EBV)-associated peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), which was clinically preceded by polymyositis. A 50-year-old woman with a 4-year history of steroid-refractory polymyositis developed ulcerative skin swelling on her left arm. A diagnosis of cytotoxic molecule (TIA-1)-positive and EBV-associated PTCL-NOS was made on the basis of immunohistochemical and molecular examinations of the biopsied brachial muscle. Combination chemotherapies were ineffective, with a fatal outcome. Reassessment of the biopsy specimens of the muscle taken at the age of 46 years showed that the PTCL was already present, indicating that the polymyositis was likely a paraneoplastic manifestation.

Combination with a defucosylated anti-HM1.24 monoclonal antibody plus lenalidomide induces marked ADCC against myeloma cells and their progenitors.

The immunomodulatory drug lenalidomide (Len) has drawn attention to potentiate antibody-dependent cellular cytotoxicity (ADCC)-mediated immunotherapies. We developed the defucosylated version (YB-AHM) of humanized monoclonal antibody against HM1.24 (CD317) overexpressed in multiple myeloma (MM) cells. In this study, we evaluated ADCC by YB-AHM and Len in combination against MM cells and their progenitors. YB-AHM was able to selectively kill via ADCC MM cells in bone marrow samples from patients with MM with low effector/target ratios, which was further enhanced by treatment with Len. Interestingly, Len also up-regulated HM1.24 expression on MM cells in an effector-dependent manner. HM1.24 was found to be highly expressed in a drug-resistant clonogenic "side population" in MM cells; and this combinatory treatment successfully reduced SP fractions in RPMI 8226 and KMS-11 cells in the presence of effector cells, and suppressed a clonogenic potential of MM cells in colony-forming assays. Collectively, the present study suggests that YB-AHM and Len in combination may become an effective therapeutic strategy in MM, warranting further study to target drug-resistant MM clonogenic cells.