The chaperone protein GRP78 released from MPN cells increases the expression of lysyl oxidase in a human stromal cell line.

Impaired function of the endoplasmic stress (ER) response causes numerous pathological conditions, including tissue fibrosis. In the present study, we aimed to determine the pathological role of ER stress response systems in myeloproliferative neoplasms (MPNs). We found increased expression of the chaperone protein glucose-regulated protein (GRP) 78, a central regulator of ER stress, in megakaryocytes from primary myelofibrosis or postessential thrombocythemia myelofibrosis patients. GRP78 was overexpressed in JAK2V617F-harboring cell lines; however, inhibitors of ER stress did not affect the expression levels of GRP78. In contrast, ruxolitinib, a well-known inhibitor of JAK2V617F, clearly blocked GRP78 expression in these cells through downregulation of transcription factor 4 (ATF4). Interestingly, GRP78 was secreted from HEL and SET-2 cells into culture media. Coculture of these cells with HS-5 cells, a human bone marrow stroma-derived cell line, induced enhanced expression of lysyl oxidase (LOX), which mediates cross-linking of collagen fibers and induces tissue fibrosis, in HS-5 cells. An anti-GRP78 neutralizing antibody abrogated LOX elevation; in contrast, recombinant GRP78 protein induced LOX protein expression in HS-5 cells. Our observations suggest that the oncogenic protein JAK2V617F induces overexpression and release of GRP78, which may induce a fibrotic phenotype in surrounding bone marrow stromal cells.

Pre-exposure prophylaxis with tixagevimab/cilgavimab for coronavirus disease 2019 (COVID-19) during the Omicron BA.5 wave at a single institution in Japan.

Pre-exposure prophylaxis with tixagevimab/cilgavimab was considered a useful strategy to protect immunocompromised patients from COVID-19 based on the phase 3 PROVENT trial conducted between November 2020 and March 2021. However, after late 2021, the dominant substrains of COVID-19 changed to Omicron substrains, which showed resistance to tixagevimab/cilgavimab. Therefore, it is important to re-evaluate the real-world efficacy of tixagevimab/cilgavimab for the prevention of COVID-19 in the Omicron era. To this end, we retrospectively evaluated the efficacy and safety of tixagevimab/cilgavimab prophylaxis for COVID-19 during the Omicron BA.5 wave in Japan. A total of 240 consecutive patients with hematologic malignancies received tixagevimab/cilgavimab at our institution from October 18, 2022, to January 31, 2023. Among them, the cumulative incidence of COVID-19 at 90 days was 6.4%. A total of 10/14 (71.4%) had mild infection, and 4/14 (28.5%) had severe infection. No patient died due to COVID-19. Adverse events consisted of deep vein thrombosis in 2 patients. Our analysis indicated that pre-exposure prophylaxis with tixagevimab/cilgavimab might have clinical effectiveness in reducing the severity of COVID-19 in Japanese HM patients, even in the Omicron BA.5 surge. It also suggested that tixagevimab/cilgavimab may be associated with cardiovascular complications.

[Hypokalemia and potassium replacement therapy in allogeneic hematopoietic stem cell transplantation].

Hypokalemia is common in allogeneic hematopoietic stem cell transplantation (allo-HCT) patients and is associated with non-relapse mortality (NRM). Therefore, it is extremely important to replace potassium adequately. We evaluated the safety and efficacy of potassium replacement therapy by retrospectively analyzing the incidence and severity of hypokalemia in 75 patients who received allo-HCT at our institution. 75% of patients developed hypokalemia during the allo-HSCT, and 44% of patients had grade 3-4 levels of hypokalemia. NRM was significantly higher in patients with grade 3-4 hypokalemia than in patients without severe hypokalemia (one-year NRM: 30% vs 7%, p=0.008). Although 75% of the patients required potassium replacement that exceeded the range of potassium chloride solutions package inserts in Japan, we did not experience any adverse events associated with hyperkalemia. Our current observations suggested that the Japanese package insert for potassium solution injection should be revised for potassium needs.

Presence of bone marrow fibrosis in multiple myeloma may predict extramedullary disease.

We analyzed the incidence of bone marrow fibrosis in 91 newly diagnosed Japanese multiple myeloma (MM) patients and evaluated the impact of fibrosis on clinical characteristics and therapeutic outcomes. Thirty-four (37%) patients had greater than grade 1 bone marrow fibrosis. The presence of bone marrow fibrosis did not affect laboratory data, the percentage of plasma cells in bone marrow or cytogenetic findings. It also had no significant effect on response to initial treatment, engraftment after autologous hematopoietic stem cell transplantation or overall survival. Interestingly, the incidence of extramedullary disease at diagnosis was significantly higher in patients with bone marrow fibrosis (p = 0.006). Analysis of biological characteristics of MM cells revealed that expression of CD49e, an alpha5/beta1 integrin, was downregulated in MM cells derived from patients with bone marrow fibrosis (p = 0.026). When seven of the original 34 patients were re-evaluated for fibrosis grading after treatment, five (71%) showed a reduction in fibrosis. Our present findings suggest that the presence of bone marrow fibrosis may predict development of extramedullary disease in MM.

Transdifferentiation of mantle cell lymphoma into sarcoma with limited neuromuscular differentiation after conventional chemotherapy.

We report an exceptionally rare case of mantle cell lymphoma (MCL) that transdifferentiated into sarcoma with limited neuromuscular differentiation. An 81-year-old man with t(11;14)-positive MCL was treated with rituximab and bendamustine and achieved complete remission; however, just 2 months later, the patient developed multiple systemic tumors. Pathologic studies revealed round cell sarcoma expressing synaptophysin, CD56, and myogenin without any B-cell markers. The CCND1 translocation and an identical IGL gene rearrangement were shared by both the MCL and sarcoma. Whole-exome sequencing detected 189 single nucleotide variants (SNVs) in the MCL and 205 SNVs in the sarcoma; 160 SNVs including NSD2, ATM, RB1, and TP53 mutations were shared between MCL and sarcoma cells. An additional PTPN11 mutation was specifically found in the sarcoma. These findings confirmed the shared clonal origin of MCL and sarcoma in this patient and indicated that MCL can transdifferentiate into sarcoma in rare cases.

[Post-transplant lymphoproliferative disorder localized to the colon presented with mild diarrhea after cord blood transplantation].

Post-transplant lymphoproliferative disorder (PTLD) usually develops with systemic symptoms, such as fever, generalized lymphadenopathy, and elevation in the lactate dehydrogenase level. Here, we present the case of a 65-year-old female patient with PTLD localized to the colon; the patient only had mild diarrhea without systemic symptoms. She had myelodysplastic syndrome and was treated with cord blood transplantation (CBT). She had a past medical history of sigmoid colon cancer treated with colonosectomy and adjuvant chemotherapy. After CBT, she achieved complete remission and was discharged after 60 days. Further, 79 days after CBT, she presented with abdominal pain. Computed tomography scan revealed adhesive ileus. The abdominal pain was resolved in 1 day with conservative treatment, however, mild diarrhea persisted. Therefore, we performed colonoscopy and found multiple ulcerative lesions in the upper colon. A pathological examination revealed PTLD. Furthermore, elevation of EBV-DNA in the blood was also confirmed. There was no detectable lesion on positron emission tomography-computed tomography (PET-CT) outside the colon; thus, we diagnosed PTLD localized into the colon that was successfully treated with rituximab. Our present experience suggests that it might be important to perform endoscopy and monitoring of EBV-DNA for early detection of PTLD, especially localized in the gastrointestinal tract.

[Vacuolar myelopathy after allogeneic bone marrow transplantation in a patient with acute lymphoblastic leukemia].

Vacuolar myelopathy (VM) is known to be a neurological complication in patients with acquired immunodeficiency syndrome (AIDS). In autopsy-based studies, VM was reported in approximately 20-50% of patients with AIDS. It manifests in various says, mainly presenting as a painless spastic paraparesis with a sensory ataxia. We present a rare case of VM after bone marrow transplantation (BMT) in a patient without AIDS. A 50-year-old man developed weakness in the lower legs, leg muscle atrophy, and difficulty in walking 86 days after BMT. The patient died from septic shock on day 309. The autopsy revealed intralamellar vacuolation in the spinal white matter, which was compatible with VM.

Geriatric nutritional risk index as a useful prognostic factor in second allogeneic hematopoietic stem cell transplantation.

Second allogeneic hematopoietic stem cell transplantation (allo-HSCT) has a low survival outcome and a high non-relapse mortality (NRM) rate which is a major obstacle to this treatment. We hypothesized that the status of malnourishment after first allo-HSCT as represented by the geriatric nutritional risk index (GNRI) could be used as a prognostic factor to determine the outcomes of second allo-HSCT. A total of 108 patients with a median age of 42 (range, 17-69) years, who received second allo-HSCT for disease recurrence after first allo-HSCT from our institution, were included in this study. Low GNRI had a significant impact on NRM at 2 years after second allo-HSCT: 56.9% in patients with GNRI ≤ 92 compared with 27.5% in patients with GNRI > 92 (P = 0.002). In multivariate analysis, GNRI of ≤ 92 was the only significant factor for NRM (hazard ratio [HR] 2.29, 95% confidence interval [CI] 1.15-4.56, P = 0.018). High-risk disease status at second allo-HSCT (HR 2.74, 95% CI 1.46-5.14, P = 0.002) and GNRI of ≤ 92 (HR 1.70, 95% CI 1.02-2.82, P = 0.042) were identified as significant factors for overall survival (OS). A score of 1 was assigned to each factor, and the OS rate at 2 years after second allo-HSCT decreased according to the score: 53.0% in patients with score 0, 32.3% with score 1, and 2.5% with score 2 (P < 0.001). In conclusion, GNRI could be a useful predictor for the outcomes of second allo-HSCT. A prospective study in other cohorts is warranted to validate the findings of our study.

Glycolytic enzyme hexokinase II is a putative therapeutic target in B-cell malignant lymphoma.

Hexokinase II (HXKII) is a key regulator of glucose metabolism that converts glucose to glucose 6-phosphate. Furthermore, HXKII blocks mitochondria-dependent apoptosis by inhibiting the release of cytochrome c. HXKII overexpression is frequently observed in several types of cancer and confers chemoresistance to cancer cells. In the present study, we found that compared with cell lines generated from diffuse large-B-cell lymphoma (DLBCL) patients, cell lines with features of Burkitt lymphoma have higher levels of HXKII because of the activation of both c-MYC and HIF-1. Under normoxia, HXKII levels were correlated with the growth ability of each B-cell lymphoma cell line. HXKII levels were further enhanced when the B-cell lymphoma cells were cultured under hypoxia. The high levels of HXKII induced by hypoxia conferred cisplatin resistance in all tested B-cell lymphoma cell lines. The HDAC inhibitor panobinostat significantly suppressed HXKII expression under both normoxic and hypoxic conditions. Importantly, panobinostat reversed the anti-lymphoma action of cisplatin, and this effect was diminished by hypoxia. These data suggest that HXKII plays different roles, including in the regulation of glycolysis and inhibition of apoptosis, depending on its expression levels. Furthermore, inhibition of HXKII expression by panobinostat may represent a new and attractive strategy to overcome cisplatin resistance.

Bone Marrow Invasion of Small Cell Neuroendocrine Carcinoma of the Endometrium: A Diagnostic Pitfall Mimicking a Haematological Malignancy.

Metastasis of cancer cells to the bone marrow is relatively rare, despite being one of the most important causes of myelosuppression in patients with solid tumours. A bone marrow examination via a biopsy is the standard method of diagnosing cancer cell invasion into the bone marrow. However, it is sometimes challenging to distinguish neuroendocrine carcinoma cells from haematopoietic cells due to their small, round shape and chromosomal abnormalities resembling haematological malignancies. We herein report a case of bone marrow invasion of small cell neuroendocrine carcinoma of the endometrium mimicking therapy-related myeloid malignancy.

Successful hematopoietic stem-cell mobilization with plerixafor plus granulocyte-colony stimulating factor in multiple myeloma patients treated with pomalidomide.

Autologous stem-cell transplantation is an effective procedure for the treatment of multiple myeloma, and involves the collection of hematopoietic stem cells (HSCs). However, in some patients, HSCs in the bone marrow fail to mobilize. Pomalidomide upregulates CXCR4 in hematopoietic stem cells, in a manner similar to that of lenalidomide, and is, thus, likely to have a negative impact on hematopoietic stem-cell mobilization in multiple myeloma patients. Here, we report the two cases in which hematopoietic stem cells were mobilized using plerixafor plus granulocyte-colony stimulating factor after exposure to lenalidomide and pomalidomide. Use of plerixafor with a sufficient washout period may lead to successful mobilization following pomalidomide use, although further study of this potential use is needed.

Combined Coagulopathy Can Induce Both Hemorrhagic and Thrombotic Complications in Multiple Myeloma.

Coagulation abnormalities are a rare but critical complication associated with plasma cell diseases. We herein present a case of multiple myeloma (MM) with complicated coagulopathy. Initially, the patient showed severe bleeding tendency due to concomitant acquired hemophilia A and acquired von Willebrand syndrome. Interestingly, the patient also exhibited hyperactivation of factor IX. During treatment for MM, the bleeding complications were ameliorated; however, the patient had central retinal vein occlusion. All of the coagulation abnormalities were completely resolved after the complete remission of MM. This case suggests that MM patients may have concomitant risks for both bleeding and thromboembolic complications.

[Atypical hemolytic uremic syndrome in an elderly patient successfully treated with eculizumab].

Herein, we present an elderly onset case of aHUS successfully treated with eculizumab. An 80-year-old woman with severe anemia, thrombocytopenia, and acute renal dysfunction was admitted to our hospital. A laboratory test revealed steep elevation in the LDH level, and the peripheral blood smear showed erythrocyte fragmentations. Accordingly, we diagnosed thrombotic microangiopathy, and treatment with plasma exchange was immediately initiated. In addition, she required hemodialysis because of rapid impairment of the renal function. After excluding Shiga toxin-producing Escherichia coli infection and malignancy and confirming her ADMTS13 activity above 10%, we diagnosed aHUS, according to the Japanese diagnostic criteria for aHUS. Next, we initiated treatment with eculizumab. Her hematological findings improved 23 days after the starting of eculizumab. In addition, her renal function gradually recovered, and hemodialysis was discontinued. The genetic test for several complement regulatory genes tested negative. The onset of aHUS is reported in children or young adults and is rarely reported in elderly. However, our case suggests the importance of precisely diagnosing aHUS and initiating early administration of eculizumab for improving the outcome even in elderly patients.

18F-FDG-PET/CT is effective in distinguishing myelofibrosis due to bone marrow infiltration of diffuse large B-cell lymphoma from triple-negative primary myelofibrosis.

Although myelofibrosis is mainly associated with myeloproliferative neoplasms (MPN), especially primary myelofibrosis (PMF), a variety of hematological malignancies, including acute myeloid leukemia, multiple myeloma and malignant lymphoma, also cause myelofibrosis with markedly varying degrees of severity. Thus, it is extremely important to accurately diagnose the underlying diseases that cause fibrosis in bone marrow. Analyses of JAK2, MPL and calreticulin gene mutations are useful for distinguishing MPN from other diseases, since 90% of MPN patients have a mutation in one of these genes. However, 10% of PMF patients do not have mutations in any of these genes, and these patients have a disease known as triple negative PMF. It is sometimes difficult to accurately distinguish triple negative PMF from secondary myelofibrosis caused by other diseases. Herein, we present a case of diffuse large B cell lymphoma (DLBCL) with bone marrow involvement, mimicking triple negative primary myelofibrosis. 18F-FDG-PET was useful for correctly diagnosing DLBCL.