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We describe a new model of myeloma bone disease in which b 2 m NOD/SCID mice injected with KMS-12-BM cells develop medullary disease after tail vein administration. Micro-computed tomography analysis demonstrated significant bone loss in the tibiae and vertebrae of diseased animals compared to controls, with loss of cortical bone (Po0.01), as well as trabecular bone volume, thickness and number (Po0.05 for all). Bone marrow of diseased animals demonstrated an increase in osteoclasts (Po0.01) and reduction in osteoblasts (Po0.01) compared to control animals. Both bone loss and osteoclast increase correlated with the degree of disease involvement. Mesenchymal stem cells (MSCs) were lentivirally transduced to express human osteoprotegerin (hOPG). Systemic administration of OPG expressing MSC reduced osteoclast activation (Po0.01) and trabecular bone loss in the vertebrae (Po0.05) and tibiae of diseased animals, to levels comparable to non-diseased controls. Because of its predominantly medullary involvement and quantifiable parameters of bone disease, the KMS-12-BM xenogeneic model provides unique opportunities to test therapies targeted at the bone marrow microenvironment.

Human MSC are easily transduced by pseudotyped lentiviral particles but there is inter-donor variation in transduction efficiency. Gene-modified MSC expressing a gene of therapeutic potential can moderate growth of haematological malignancies.

Numerous outbreaks of adenovirus infection from different types of health care settings, except a hematology unit, have been reported. This is the first report describing an outbreak of adenovirus infection causing diarrhea among adult hematopoietic stem cell transplant recipients. Six of 21 patients from the outbreak cohort were affected with diarrhea. Electron microscopy, cell culture, and direct DNA sequencing of amplicons generated from stool and blood samples were used to investigate this outbreak. Electron microscopy and cell culture detected adenovirus in stools from symptomatic patients. DNA sequencing of amplicons generated from stool samples confirmed nosocomial transmission of infection from a single index case. The outbreak strain was also detected in plasma of four of these patients, suggesting systemic infection. The outbreak strain was identified as type 12. Standard infection control measures were effective to control this outbreak.

Summary Myeloma patients frequently respond poorly to bacterial and viral vaccination. A few studies have reported poor humoral immune responses in myeloma patients to COVID‐19 vaccination. Using a prospective study of myeloma patients in the UK Rudy study cohort, we assessed humoral and interferon gamma release assay (IGRA) cellular immune responses to COVID‐19 vaccination post second COVID‐19 vaccine administration. We report data from 214 adults with myeloma (n = 204) or smouldering myeloma (n = 10) who provided blood samples at least three weeks after second vaccine dose. Positive Anti‐spike antibody levels (> 50 iu/ml) were detected in 189/203 (92.7%), positive IGRA responses were seen in 97/158 (61.4%) myeloma patients. Only 10/158 (6.3%) patients were identified to have both a negative IGRA and negative anti‐spike protein antibody response. In all, 95/158 (60.1%) patients produced positive results for both anti‐spike protein serology and IGRA. After adjusting for disease severity and myeloma therapy, poor humoral immune response was predicted by male gender. Predictors of poor IGRA included anti‐CD38/anti‐BCMA (B‐cell maturation antigen) therapy and Pfizer‐BioNTech vaccination. Further work is required to understand the clinical significance of divergent cellular response to vaccination.

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Myeloma remains incurable with a median survival of 4 years, but outcome can be improved by the use of high-dose therapy. We used the etoposide, methylprednisolone, cytarabine and cisplatin (ESHAP) regimen as second-line therapy in 42 newly diagnosed myeloma patients who had failed vincristine, adriamycin and dexamethasone (VAD)- type therapy (n = 36), responded to first-line treatment but persisted in having significant residual marrow plasmacytosis (n = 5) or failed prior stem cell harvesting (n = 1), with the dual aim of improving disease response and mobilizing peripheral blood stem cells. Fourteen of 21 (67%) patients with no change or progressive disease after VAD responded to ESHAP; seven of 12 (58%) patients with minor response converted to partial response. Marrow plasmacytosis fell from a median of 52% at diagnosis to 23.5% after primary therapy and to15% after ESHAP. ESHAP chemotherapy was well-tolerated. There were 11 admissions due to febrile neutropenia (n = 7), nausea and vomiting (n = 2), pneumonia (n = 1) and perforated bowel (n = 1). Renal function deteriorated in 13 of 42 patients after ESHAP, but none required renal support. ESHAP mobilization was performed in 32 patients of whom 87% achieved a CD34(+) yield >2 x 10(6)/kg. In all, 38 patients proceeded to high-dose therapy. The overall survival for all patients was 62% at 4 years following ESHAP. We conclude that ESHAP has acceptable toxicity and efficient stem cell mobilizing capability, effectively cytoreduced this chemoresistant group of patients, and did not appear to adversely affect transplant outcome.

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