Primary myelofibrosis (PMF) is a myeloproliferative neoplasm (MPN) characterized by clonal myeloproliferation, progressive bone marrow (BM) fibrosis, splenomegaly, and anemia. BM fibrosis was ...previously thought to be a reactive phenomenon induced by mesenchymal stromal cells that are stimulated by the overproduction of cytokines such as transforming growth factor (TGF)-β1. However, the involvement of neoplastic fibrocytes in BM fibrosis was recently reported. In this study, we showed that the vast majority of collagen- and fibronectin-producing cells in the BM and spleens of Jak2V617F-induced myelofibrosis (MF) mice were fibrocytes derived from neoplastic hematopoietic cells. Neoplastic monocyte depletion eliminated collagen- and fibronectin-producing fibrocytes in BM and spleen, and ameliorated most characteristic MF features in Jak2V617F transgenic mice, including BM fibrosis, anemia, and splenomegaly, while had little effect on the elevated numbers of megakaryocytes and stem cells in BM, and leukothrombocytosis in peripheral blood. TGF-β1, which was produced by hematopoietic cells including fibrocytes, promoted the differentiation of neoplastic monocytes to fibrocytes, and elevated plasma TGF-β1 levels were normalized by monocyte depletion. Collectively, our data suggest that neoplastic fibrocytes are the major contributor to BM fibrosis in PMF, and TGF-β1 is required for their differentiation.
The occurrence of a mediastinal germ cell tumor (GCT) and hematological malignancy in the same patient is very rare. Due to its rarity, there have been only two reports of the concurrent cases ...undergoing detailed genetic analysis with whole-exome sequencing (WES), and the possible clonal relationship between the both tumors remained not fully elucidated.
We performed whole-exome sequencing analysis of mediastinal GCT and acute myeloid leukemia (AML) samples obtained from one young Japanese male adult patient with concurrent both tumors, and investigated the possible clonal relationship between them.
Sixteen somatic mutations were detected in the mediastinal GCT sample and 18 somatic mutations in the AML sample. Mutations in nine genes, including TP53 and PTEN both known as tumor suppressor genes, were shared in both tumors.
All in our case and in the previous two cases with concurrent mediastinal GCT and AML undergoing with whole-exome sequencing analysis, TP53 and PTEN mutations were commonly shared in both tumors. These data not only suggest that these tumors share a common founding clone, but also indicate that associated mediastinal GCT and AML harboring TP53 and PTEN mutations represent a unique biological entity.
Whether human T-lymphotropic virus type 1 (HTLV-1) carriers can develop sufficient humoral immunity after coronavirus disease 2019 (COVID-19) vaccination is unknown.
To investigate humoral immunity ...after COVID-19 vaccination in HTLV-1 carriers, a multicenter, prospective observational cohort study was conducted at five institutions in southwestern Japan, an endemic area for HTLV-1. HTLV-1 carriers and HTLV-1-negative controls were enrolled for this study from January to December 2022. During this period, the third dose of the COVID-19 vaccine was actively administered. HTLV-1 carriers were enrolled during outpatient visits, while HTLV-1-negative controls included health care workers and patients treated by participating institutions for diabetes, hypertension, or dyslipidemia. The main outcome was the effect of HTLV-1 infection on the plasma anti-COVID-19 spike IgG (IgG-S) titers after the third dose, assessed by multivariate linear regression with other clinical factors.
We analyzed 181 cases (90 HTLV-1 carriers, 91 HTLV-1-negative controls) after receiving the third dose. HTLV-1 carriers were older (median age 67.0 vs. 45.0 years, p < 0.001) and more frequently had diabetes, hypertension, or dyslipidemia than did HTLV-1-negative controls (60.0% vs. 27.5%, p < 0.001). After the third dose, the IgG-S titers decreased over time in both carriers and controls. Multivariate linear regression in the entire cohort showed that time since the third dose, age, and HTLV-1 infection negatively influenced IgG-S titers. After adjusting for confounders such as age, or presence of diabetes, hypertension, or dyslipidemia between carriers and controls using the overlap weighting propensity score method, and performing weighted regression analysis in the entire cohort, both time since the third dose and HTLV-1 infection negatively influenced IgG-S titers.
The humoral immunity after the third vaccination dose is impaired in HTLV-1 carriers; thus, customized vaccination schedules may be necessary for them.
Acquired mutations of JAK2 and TET2 are frequent in myeloproliferative neoplasms (MPNs). We examined the individual and cooperative effects of these mutations on MPN development. Recipients of ...JAK2V617F cells developed primary myelofibrosis–like features; the addition of loss of TET2 worsened this JAK2V617F-induced disease, causing prolonged leukocytosis, splenomegaly, extramedullary hematopoiesis, and modestly shorter survival. Double-mutant (JAK2V617F plus loss of TET2) myeloid cells were more likely to be in a proliferative state than JAK2V617F single-mutant myeloid cells. In a serial competitive transplantation assay, JAK2V617F cells resulted in decreased chimerism in the second recipients, which did not develop MPNs. In marked contrast, cooperation between JAK2V617F and loss of TET2 developed and maintained MPNs in the second recipients by compensating for impaired hematopoietic stem cell (HSC) functioning. In-vitro sequential colony formation assays also supported the observation that JAK2V617F did not maintain HSC functioning over the long-term, but concurrent loss of TET2 mutation restored it. Transcriptional profiling revealed that loss of TET2 affected the expression of many HSC signature genes. We conclude that loss of TET2 has two different roles in MPNs: disease accelerator and disease initiator and sustainer in combination with JAK2V617F.
•Loss of TET2 accelerates the degree of malignancy of MPNs in combination with JAK2V617F.•Loss of TET2 sustains MPNs in combination with JAK2V617F.
Polycythemia vera (PV) and essential thrombocythemia (ET) are associated with life-threatening thrombohemorrhagic events, and disease progression and development of non-hematological malignancies ...also reduce long-term survival. We retrospectively surveyed thrombohemorrhagic events and overall survival (OS) in 62 PV and 117 ET patients. The cumulative incidences of thrombohemorrhagic events in PV and ET patients were 11.3 and 10.3%, and the incidence rates were 2.42 and 1.85 per 100 person-years. The combined incidence rates of disease progression and development of non-hematological malignancies in PV and ET patients were 1.73 and 1.69 per 100 person-years. The incidence rates of thrombohemorrhagic events in our Japanese PV/ET patients were lower than those reported by most Western studies, but were comparable to those in the largest prospective observational study in ET patients. The combined incidence rates of disease progression and development of non-hematological malignancies were similar between Japanese and Western PV/ET patients. In ET patients, the conventional risk stratification model based on the presence of advanced age or history of thrombosis was useful to predict thrombosis risk, and both the conventional model and the International Prognostic Score of thrombosis in ET based on the above 2 risk factors plus increased leukocyte count could predict poor survival.
A new entity, namely early/prefibrotic primary myelofibrosis (PMF), was introduced as a subtype of PMF in the 2016 revised World Health Organization (WHO) criteria for myeloproliferative neoplasms ...(MPN). It was diagnosed based on histopathological features of bone marrow (BM) biopsy specimens together with clinical parameters leukocytosis, anemia, elevated lactate dehydrogenase (LDH) values, and splenomegaly. The aim of this study was to evaluate the prevalence of early/prefibrotic PMF in patients who were previously diagnosed with ET, and to compare clinical features at diagnosis and outcomes between early/prefibrotic PMF and essential thrombocythemia (ET) patients. BM biopsy samples obtained at the time of ET diagnosis were available in 42 patients. Sample reevaluation according to the 2016 revised WHO criteria revealed that early/prefibrotic PMF accounted for 14% of patients who were previously diagnosed with ET, which was comparable to the rates in previous reports. Compared to patients with ET, patients with early/prefibrotic PMF had higher LDH values and higher frequencies of splenomegaly. Overall, myelofibrosis-free and acute myeloid leukemia-free survivals were comparable between the 2 groups. Accurate diagnosis is required to clarify the clinical features of Japanese ET patients.
A retrospective chart survey of the clinical features of indolent adult T-cell leukemia/lymphoma (ATL) was conducted in the Miyazaki Prefecture, Japan. This study enrolled 24 smoldering-type ATLs, 10 ...favorable chronic-type ATLs, and 20 unfavorable chronic-type ATLs diagnosed between 2010 and 2018. Among them, 4, 3, and 10 progressed to acute-type ATLs during their clinical course. The median survival time (MST) in smoldering-type ATL and favorable chronic-type ATL was not reached, and their 4-year overall survival (OS) was 73% and 79%, respectively. Compared with this, the prognosis of unfavorable chronic-type ATL was poor. Its MST was 3.32 years, and the 4-year OS was 46% (p = 0.0095). In addition to the three features that determine the unfavorable characteristics of chronic-type ATL, namely, increased lactate dehydrogenase, increased blood urea nitrogen, and decreased albumin, the high-risk category by the indolent ATL-Prognostic Index, which was defined by an increment of soluble interleukin-2 receptor (sIL2-R) of >6000 U/mL, could explain the poor prognosis in indolent ATL patients. The level of sIL-2R might be an indicator of the initiation of therapy for indolent ATL.
Monocyte-derived fibrocytes play an important role in the progression of fibrosis in the skin, lungs, heart and kidney. However, the contribution of fibrocytes to liver fibrosis is unclear. The aim ...of this study was to investigate whether fibrocytes contributed to fibrosis progression in the livers of carbon tetrachloride (CCl4)-treated mice.
C57BL/6J mice were divided into 4 groups: normal control group, CCl4-treated group, CCl4 + control liposome-treated group, and CCl4 + clodronate liposome-treated group. For the elimination of systemic monocyte and monocyte-derived fibrocyte, one group was treated with clodronate liposome, and another group with control liposome as a control. After 4 weeks of treatment, hepatic mononuclear cells were subjected to immunofluorescent (IF) staining and fluorescence-activated cell sorter (FACS) analysis to detect fibrocytes. Measurement of collagen-positive Sirius red stained area and collagen-I mRNA expression in the liver were performed to evaluate the degree of liver fibrosis quantitatively.
In the liver of the CCl4-treated and CCl4 + control liposome-treated groups, the number of fibrocytes, the area positive for Sirius red staining and collagen-I mRNA expression significantly increased compared with those in the normal control group. In the liver of the CCl4 + clodronate liposome-treated group, few fibrocytes was observed as in the normal control group, but Sirius red staining positive area and collagen-I mRNA expression were increased and equivalent to the CCl4-treated and CCl4 + control liposome-treated groups.
Monocyte-derived fibrocytes play a minimal role in CCl4-induced liver fibrosis. Cells other than fibrocytes such as hepatic stellate cells play a central role in liver fibrosis.
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