IgG4-related disease (IgG4RD) is a multi-organ disorder characterized by an elevated serum IgG4 level and IgG4-positive plasma cell infiltration of the affected organs, accompanied by tissue fibrosis ...and sclerosis. Although it can affect any organ, to our knowledge, no cases involving concurrent autoimmune neutropenia and thrombocytopenia have been reported. A 62-year-old man visited our hospital and was diagnosed with IgG4RD accompanied by interstitial pneumonitis, lymphadenopathy, and interstitial nephritis. During his clinical course, he developed autoimmune neutropenia and idiopathic thrombocytopenic purpura. Our case, invoving multiple hematological abnormalities, might help deepen our understanding of the pathophysiology of IgG4RD.
Autologous stem cell transplantation (ASCT) with high-dose thiotepa and busulfan is a treatment option for patients with central nervous system (CNS) lymphoma. We report here the occurrence of ...secondary failure of platelet recovery (SFPR) in three out of 24 patients who received high-dose thiotepa and busulfan followed by ASCT. Although there was no obvious abnormality in the primary platelet engraftment as well as the recovery of other blood cells, they developed SFPR with a median time to onset of day 38, and the platelets gradually recovered over several months with steroid therapy. During the same period, there was no development of SFPR among 50 patients who received ASCT with a conditioning regimen of MEAM (ranimustine, etoposide, cytarabine, and melphalan) or high-dose melphalan. However, one of the two patients who received a conditioning regimen of busulfan and melphalan developed SFPR, suggesting that the use of a busulfan-based conditioning regimen may be one of the risk factors for SFPR. It is important to be aware of this possible adverse effect of ASCT with high-dose thiotepa and busulfan to ensure timely diagnosis and prevention of subsequent serious complications.
A 54-year-old woman was referred to our hospital for pancytopenia and liver dysfunction, and with no personal or family history of hemophagocytic lymphohistiocytosis (HLH). Although the etiology was ...unknown, she was diagnosed with HLH. She experienced exacerbation of HLH even after initiating systemic chemotherapy with etoposide, dexamethasone, and cyclosporine. Furthermore, flow cytometric analysis of the natural killer cells revealed a reduction in perforin expression, and DNA sequencing of the perforin gene (PRF1) revealed two known mutations, confirming the diagnosis of late-onset familial HLH type 2. She received an allogeneic stem cell transplant from an unrelated human leukocyte antigens identical donor, but developed thrombotic microangiopathy, and succumbed to septic shock shortly after the transplant. Previously, HLH in adults was believed to develop from underlying diseases. However, as in our case, several reports demonstrated that HLH gene mutations could be found even after adolescence. Adult with HLH with no underlying disorders should undergo early HLH-associated gene testing for confirmatory diagnosis.
Paraneoplastic neurological disorders (PND) are neurological effects of malignancy that are recognized as immune-mediated disorders caused by aberrant expression of a tumor antigen that is normally ...expressed in the nervous system. We report a case of cerebellar ataxia which turned out to be paraneoplastic cerebellar degeneration, a subtype of PND that develops cerebellar symptoms, that was caused by follicular lymphoma. After chemotherapy, the patient attained sufficient improvement of cerebellar symptoms along with complete remission of lymphoma. Paraneoplastic cerebellar degeneration should be recognized as a rare complication of lymphoma as it is important to start proper treatment before the neurological symptoms become irreversible.
Adult T-cell leukemia (ATL) is a peripheral CD4+ T-cell neoplasm caused by human T-cell leukemia virus type 1 (HTLV-1). Despite several investigations using human specimens and mice models, the exact ...origin of ATL cells remains unclear. Here we provide a new insight into the hierarchical architecture of ATL cells. HTLV-1–infected cells and dominant ATL clones are successfully traced back to CD45RA+ T memory stem (TSCM) cells, which were recently identified as a unique population with stemlike properties, despite the fact that the majority of ATL cells are CD45RA–CD45RO+ conventional memory T cells. TSCM cells from ATL patients are capable of both sustaining themselves in less proliferative mode and differentiating into other memory T-cell populations in the rapidly propagating phase. In a xenograft model, a low number of TSCM cells efficiently repopulate identical ATL clones and replenish downstream CD45RO+ memory T cells, whereas other populations have no such capacities. Taken together, these findings demonstrate the phenotypic and functional heterogeneity and the hierarchy of ATL cells. TSCM cells are identified as the hierarchical apex capable of reconstituting identical ATL clones. Thus, this is the first report to demonstrate the association of a T-cell malignancy with TSCM cells.
•ATL clones are preserved in a rare CD4+CD45RA+ TSCM population.•ATL-TSCM cells unidirectionally produce conventional CD45RO+ ATL cells and show a high potency of repopulating identical ATL clones in vivo.
Adult T-cell leukemia (ATL) is an aggressive T-cell malignancy caused by human T-cell leukemia virus type 1. Because of its immunosuppressive property and resistance to treatment, patients with ATL ...have poor prognoses. ATL cells possess the regulatory T cell (Treg) phenotype, such as CD4 and CD25, and usually express forkhead box P3 (FOXP3). However, the mechanisms of FOXP3 expression and its association with Treg-like characteristics in ATL remain unclear. Selective demethylation of the Treg-specific demethylated region (TSDR) in the FOXP3 gene leads to stable FOXP3 expression and defines natural Tregs. Here, we focus on the functional and clinical relationship between the epigenetic pattern of the TSDR and ATL. Analysis of DNA methylation in specimens from 26 patients with ATL showed that 15 patients (58%) hypomethylated the TSDR. The FOXP3(+) cells were mainly observed in the TSDR-hypomethylated cases. The TSDR-hypomethylated ATL cells exerted more suppressive function than the TSDR-methylated ATL cells. Thus, the epigenetic analysis of the FOXP3 gene identified a distinct subtype with Treg properties in heterogeneous ATL. Furthermore, we observed that the hypomethylation of TSDR was associated with poor outcomes in ATL. These results suggest that the DNA methylation status of the TSDR is an important hallmark to define this heterogeneous disease and to predict ATL patient prognosis.
Background: Histone methylation is one of the major systems of epigenetics and reversibly regulated by lysine (K) specific methyltransferases (KMTs) and demethylases (KDMs). Dysregulation of KMTs ...such as EZH2 and MLL play a key role in the pathogenesis of acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) while the precise function of KDMs remains unclear.KDM1A is the first reported histone demethylase, which mainly catalyzes demethylation of mono- and di-methylated lysine 4 of histone 3 (H3K4me1 and me2 respectively). According to recent reports, the inhibition of KDM1A either alone or in combination of all-trans retinoic acid is effective for AML expressing MLL-AF9 or for several types of AML respectively, suggesting KDM1A could be a therapeutic target of AML. However, other reports argue that KDM1A is essential in hematopoiesis, raising concern that KDM1A-targeted therapy could lead to severe hematological toxicity. Here, we try to clarify what types of leukemia can be ameliorated by the pharmacological inhibition of KDM1A with a possible therapeutic window and what are functional and molecular mechanisms utilizing highly selective KDM1A inhibitors we have newly designed.
Results: First we validated the effect of our novel inhibitors on murine leukemia cells harboring MLL-AF9. In accordance with a previous report, our novel KDM1A inhibitors suppressed cell proliferation, diminished clonogenic capacity and induced G1-S cell cycle arrest and myelomonocytic differentiation but not apoptosis in quite low concentration that clonogenicity of normal murine bone marrow cells was spared. Next we examined the effect of these drugs on diverse types of human myeloid leukemia cells and found that our drugs were particularly effective in erythroid leukemia cells (HEL), megakaryocytic leukemia cells (CMK11-5), and a blastic subline from a MDS patient with complex karyotype (MDS-L). MDS-L cells were changed phenotypically and morphologically towards myelomonocytic differentiation such as the increase of CD11b expression level and the induction of neutrophil-like cells. HEL and CMK cells which are negative for myelomonocytic markers also gained CD11b expression and decreased erythroid markers such as CD235a and CD71. These data suggest that the inhibition of KDM1A induces myeloid differentiation across various types of leukemia.
To investigate an underlying molecular basis for the cell fate conversion in HEL and myeloid differentiation in MDS-L by the inhibition of KDM1A, we performed gene expression profiling and analyzed a change of gene signatures. The expression pattern of transcriptional factors was changed from the erythroid signature (e.g. GATA1 and TAL1) to the myeloid signature (e.g. SPI1 and CEBPA) in HEL. Gene Set Enrichment Analysis (GSEA) showed that the myeloid differentiation-associated gene signature was positively enriched and the leukemia stem cell-associated gene signature was negatively enriched in both HEL and MDS-L.
Finally, we investigated the effect of our KDM1A inhibitors on primary human samples such as AML with MLL-AF9 and MDS in the phase of overt leukemia (MDS/AML) with complex karyotype. The colony formation capacity was clearly impaired in relatively low concentration that normal colonies were spared. We transplanted primary MDS/AML cells with complex karyotype to immunodeficient mice and treated with a KDM1A inhibitor or vehicles after confirming the engraftment. In one MDS/AML case, all mice treated with vehicles (n=4) died of anemia and the increase of human leukemia cells within four months while 3 of 4 mice treated with a KDM1A inhibitor have survived for more than six months. Also in another case, both of two vehicle-treated mice died while all drug-treated mice had survived for more than six months. At day 200 after transplantation, we sacrificed all survived mice treated with a KDM1A inhibitor and found that human blasts were displaced from the bone marrow of treated mice. Those data suggest that our KDM1A inhibitor is effective in vivo and have a possibility for the clinical application.
Conclusion: Our study suggests that KDM1A involves with myeloid differentiation and the leukemia stem cell signature and that the pharmacological inhibition of KDM1A by highly selective inhibitors is a promising way to ameliorate AML with poor prognosis such as erythroleukemia and MDS/AML with complex karyotype, without impairing normal hematopoiesis.
No relevant conflicts of interest to declare.
Adult T-cell leukemia (ATL) is a mature T cell neoplasm causatively associated with HTLV-1. It takes a long period, around 50 years, to develop ATL after the transmission of HTLV-1 in infancy through ...breastfeeding, suggesting the pool for the generation of ATL clone may exist somewhere. Recent reports showed human CD34+ bone marrow cells infected by HTLV-1 ex vivo can generate CD4+ T-cell lymphomas in immunodeficiency mice or that CD117+ early hematopoietic progenitors can develop lymphoma in transgenic mice model of Tax which is an oncogenic protein of HTLV-1. These results suggest the model of leukemia initiating cells, that leukemia is organized hierarchically and sustained by a small subset of stem/progenitors at the apex, might be acceptable in ATL. A more recent report demonstrated that a novel compartment of normal T cells, termed stem cell memory T cells (TSCM), possesses stem cell-like capacity including relatively enhanced self-renewal capacity and multipotent ability to generate all memory and effector T cell subsets. This concept prompts us to hypothesize that TSCM subset might contribute to the development of ATL.
First, to investigate whether hematopoietic stem/progenitor cells in primary samples of ATL patients are infected with HTLV-1, we sorted lineage(CD3, CD4, CD8, CD11b, CD14, CD19, CD20, CD56, CD235)-negative CD34+ cells from bone marrow samples of ATL patients by FACS AriaII, purified genomic DNA, and then performed PCR of pX region which is a virus specific gene. No amplification of pX was detected in all samples we studied.
Next, to focus on TSCM population, we established the eight-color staining method with lineage of NK/Monocyte/DC (CD11b, CD14 and CD56), CD4, CD45RA, CD45RO, CCR7, CD95, CD122 and CD25. We successfully separated CD4+ T cells from ATL patients into four subsets; naïve T (TN: CD4+CD45RA+CD45RO-CCR7+CD95-CD122-), stem cell memory T (TSCM: CD4+CD45RA+CD45RO-CCR7+CD95+CD122dim), central memory T (TCM: CD4+CD45RA-CD45RO+CCR7+), and effector memory T (TEM: CD4+CD45RA-CD45RO+CCR7-). Although ATL cells are generally CD45RO positive, so that TCM and TEM were extremely dominant, CD45RA positive populations did exist in all ATL samples we studied.
To assess the frequency of infected cells, we performed quantitative PCR with the sensitivity of 5 copies detectable at the minimum and calculated by dividing copy number of pX in HTLV-1 provirus with that of RNase P in human genome in genomic DNA from 1,000 cells of each subset. Almost all cells in TCM and TEM and more than 10% of cells in TSCM were infected in most of cases while none of infected cells were detected in TN in our experiment design. Since ATL is caused by monoclonal expansion from plenty of HTLV-1 infected clones, we focused on the existence of ATL original clone in each subset. We determined the ATL original clone by inverse PCR and the clone-specific provirus integration site by sequencing of the inverse PCR product in each case, and then constructed PCR primers being capable of detecting each ATL original clone by regular PCR. Interestingly we found each ATL clone was detected in TSCM, TCM, and TEM but not in TN subset in all studied cases, indicating TSCM could be an origin of ATL cells.
To investigate whether there is a hierarchy in ATL cells, we next performed in vitro culture with IL-7 and examined the status of CD45RA and CCR7 after 2 weeks. Intriguingly TSCM generated TCM and TEM while TCM and TEM did not generate TSCM, suggesting TSCM is an apex in HTLV-1 infected T cells.
To investigate tumorigenicity of TSCM, we adopted xenogeneic transplantation assay. When we inoculated 3x104 cells of each subset from one ATL patient into immune deficient mice (NOG mice) intraperitoneally, we observed high number of cells in peripheral blood and spleen of recipient mice transplanted with TSCM compared to TCM and TEM. Phenotypically TCM and TEM were generated in mice transplanted with TSCM as well as TCM and TEM while TSCM was only generated from TSCM but not TCM and TEM. Furthermore we analyzed the clonality of engrafted cells by ATL clone-specific PCR and inverse PCR, and found that the patient original clone becomes dominant in recipient mice inoculated with TSCM but not in those with TCM and TEM.
Taken together, our findings provide new insights that TSCM could be an apex of the hierarchy of ATL and play an important role in development and maintenance of ATL clone.
No relevant conflicts of interest to declare.
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