[Spontaneous regression of HIV-associated EBV-positive mucocutaneous ulcer due to immune reconstruction with antiretroviral therapy].

A 24-year-old man was found to have an ileocecal ulcer by colonoscopy. A pathological diagnosis of diffuse large B-cell lymphoma (DLBCL) with diffuse positive reaction of Epstein-Barr encoding region (EBER) by in situ hybridization was made based on analysis of the specimen. Acquired immunodeficiency syndrome (AIDS) complicated by pneumocystis jirovecii pneumonia was also diagnosed. As no other significant lymphomatous lesions were identified by further examination, a clinical diagnosis of EBV-positive mucocutaneous ulcer (EBVMCU) was made. Rather than performing systemic chemotherapy, the lesion was closely monitored and antiretroviral therapy (ART) for AIDS was started with the hope of treating the lesion through immune reconstitution. The lesion had completely disappeared by day 79 after starting ART, and has not recurred for over 3 years. EBVMCU is known to develop secondary to various immunosuppressive states including AIDS. Here we report a rare case of EBVMCU detected at diagnosis of AIDS that entered complete remission after immune reconstitution by ART.

Identification of putative noncanonical driver mutations in patients with essential thrombocythemia.

Essential thrombocythemia (ET) cases without canonical JAK2, CALR, or MPL mutations, that is, triple-negative (TN) ET, have been found in 10%-20% of ET cases. Owing to the limited number of TN ET cases, its clinical significance remains unclear. This study evaluated TN ET's clinical characteristics and identified novel driver mutations. Among 119 patients with ET, 20 (16.8%) had no canonical JAK2/CALR/MPL mutations. Patients with TN ET tended to be younger and had lower white blood cell counts and lactate dehydrogenase values. We identified putative driver mutations in 7 (35%): MPL S204P, MPL L265F, JAK2 R683G, and JAK2 T875N were previously reported as candidate driver mutations in ET. Moreover, we identified a THPO splicing site mutation, MPL*636Wext*12, and MPL E237K. Four of the seven identified driver mutations were germline. Functional studies on MPL*636Wext*12 and MPL E237K revealed that they are gain-of-function mutants that increase MPL signaling and confer thrombopoietin hypersensitivity with very low efficiency. Patients with TN ET tended to be younger, although this was thought to be due to the inclusion of germline mutations, hereditary thrombocytosis. Accumulating the genetic and clinical characteristics of noncanonical mutations may help future clinical interventions in TN ET and hereditary thrombocytosis.

Prediction of the risk for graft versus host disease after allogeneic hematopoietic stem cell transplantation in patients treated with mogamulizumab.

Mogamulizumab (Mog), an anti-C-C motif chemokine receptor 4 (CCR4) antibody, is a therapeutic for adult T-cell leukemia/lymphoma (ATL). Injuries of normal regulatory T cells (Tregs) which express CCR4 by Mog could result in immune-related adverse events including graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). In this study, we retrospectively analyzed 25 patients among 39 patients with ATL who received allo-HSCT. We found that the risk of grade II to IV GVHD was higher in patients who received Mog before or after allo-HSCT (Mog+) than in those who did not (Mog-). The incidence of severe intestinal GVHD and cytomegalovirus (CMV) enteritis were significantly higher in Mog + patients and resulted in death from GVHD or CMV enteritis. Treg numbers were suppressed until Mog serum concentrations became undetectable. Measuring the concentration of Mog and/or the number of Tregs at the time of allo-HSCT might predict the risk of GVHD.

RLTPR Q575E: A novel recurrent gain-of-function mutation in patients with adult T-cell leukemia/lymphoma.

OBJECTIVES: Adult T-cell leukemia/lymphoma (ATL) is an intractable T-cell malignancy caused by long-term infection with human T-cell leukemia virus type-1 (HTLV-1). While ATL pathogenesis has been associated with HTLV-1-derived oncogenic proteins, including Tax and HBZ, the contribution of genomic aberrations remains poorly defined. METHODS: To elucidate the genomic basis of ATL, whole exome sequencing was performed on cells from 47 patients with aggressive ATL. RESULTS: We discovered the novel mutation RLTPR Q575E in four patients (8.5%) with a median variant allele frequency of 0.52 (range 0.11-0.68). Despite being reported in cutaneous T-cell lymphoma, three ATL patients carrying RLTPR Q575E lacked skin involvement. Patients carrying RLTPR Q575E also harbored CARD11 (75%), PLCG1 (25%), PRKCB (25%), or IKBKB (25%) mutations related to TCR/NF-κB signaling. Jurkat cells transfected with RLTPR Q575E cDNA displayed increased NF-κB activity and significantly increased IL-2 mRNA levels under stimulation. RLTPR Q575E increased the interaction between RLTPR and CARD11, while RLTPR directly interacted with Tax. CONCLUSIONS: We identified, and functionally validated, a novel gain-of-function mutation in patients with aggressive ATL. During TCR activation by Tax or gain-of-function mutations, RLTPR Q575E selectively upregulates NF-κB signaling and may exert oncogenic effects on ATL pathogenesis.

[Adult T-cell leukemia-lymphoma with severe hepatic damage and fluid retention successfully treated with mogamulizumab].

Adult T-cell leukemia-lymphoma (ATL) is a peripheral T-cell malignancy caused by the human T-cell lymphotropic virus, type I and it has an extremely poor prognosis. A 66-year-old man with severe hepatic damage, massive pleural effusion and ATL cell infiltration-induced ascites was referred to our department. Reduced-intensity cytotoxic chemotherapy was attempted, but could not continue due to persistent hyperbilirubinemia. Laboratory results also showed elevated lactate dehydrogenase (LDH) and serum albumin levels were profoundly decreased. A humanized monoclonal antibody against chemokine receptor type 4 (CCR4), mogamulizumab (Moga), was thereby challenged and it successfully resolved the hepatic damage. Finally, a standard dose of chemotherapy could be administered, and it induced a complete remission. The patient is still in remission more than three years after the final dosage of standard chemotherapy. These results indicate that Moga, whose pharmacokinetics are not significantly influenced by hepatic function or serum albumin, could be a promising treatment option for patients with ATL complicated by severe hepatic damage due to infiltration of ATL cells.

Essential thrombocytosis attributed to JAK2-T875N germline mutation.

The aim of this study was to elucidate the role of a non-canonical JAK2 mutation JAK2-T875N, which was identified by exome sequencing in a patient with essential thrombocytosis (ET) who had a family history of suspecting ET. Whole exome sequencing was performed on peripheral blood mononuclear cells and buccal swab-derived genomic DNA. Sanger sequencing was performed to confirm the variant. We evaluated the function of the mutation on JAK2 activity and downstream signaling (Erk, STATs) using JAK2-T875N-transfected or transduced cell lines. 293T cells transfected with JAK2 cDNA carrying V617F or T875N mutations showed increased levels of phosphorylated JAK2 and Erk. Enhanced STAT3 and STAT5 activity was confirmed by promoter assay. JAK2-T875N-transduced Ba/F3 cells showed increased cellular growth without IL-3 stimulation. To our knowledge, this is the first case of ET caused by JAK2-T875N mutation with a family history of thrombocytosis and cerebral infarction.

Clinical significance of CD70 expression on T cells in human T-lymphotropic virus type-1 carriers and adult T cell leukemia/ lymphoma patients.

Human T-lymphotropic virus type 1 (HTLV-1) is the causative agent of adult T-cell leukemia/lymphoma (ATL). Miscellaneous host immune surveillance systems control T-cell growth/leukemogenesis during HTLV-1 infection. We characterized CD70 and CD27 expression on lymphocytes of HTLV-1 carriers and patients with ATL (study approved by the local Medical Ethical Committee). High CD70 expression was observed on CD4 + CD25+ T cells from patients with acute-type ATL, while patients with smoldering- or chronic-type ATL and HTLV-1 carriers exhibited lower expression. Furthermore, significantly higher CD27 expression was observed on HTLV-1-specific CTLs. We found an association between CD70 expression on CD4 + T cells and HTLV-1 infection; increased CD70 expression was observed after exposure to Tax. Moreover, addition of anti-CD70 antibodies enhanced the CD107a surface mobilization of HTLV-1 Tax-specific CTLs following Tax-peptide stimulation in the PBMCs of carriers. These data demonstrate the important role of the CD70/CD27 axis in immune responses in HTLV-1 carriers and ATL patients.

A new ATL xenograft model and evaluation of pyrrolidine dithiocarbamate as a potential ATL therapeutic agent.

Adult T-cell leukemia/lymphoma (ATL) is caused by human T-lymphotrophic virus type 1 infection and is one of the most refractory malignant T-cell lymphomas. Improvement of ATL therapy options requires the establishment of appropriate ATL animal models. In this study, we successfully generated an ATL mouse model by xenotransplantation of primary peripheral blood mononuclear cells (PBMCs) isolated from ATL patients (ATL cells) into nonobese diabetic/severe combined immunodeficiency/Jak3-null mice (NOJ mice). To generate the model, the ATL S1T cell line was subcutaneously injected into mice. Primary ATL cells were then transplanted subcutaneously, intraperitoneally, or intravenously. ATL cells infiltrated multiple organs, and elevated human soluble interleukin 2 receptor (IL-2R) levels were detected in peripheral blood. Injection of one million primary ATL cells was needed for successful engraftment into host mice. Thawed cells, frozen long-term in liquid nitrogen, could also be transplanted; however, more cells were required to achieve similar results. The median mouse survival time was proportional to the number of cells injected. Successful secondary transplantation of ATL cells from one NOJ mouse into another was achieved and confirmed by T-cell receptor analysis. Finally, we examined the effects of the antioxide pyrrolidine dithiocarbamate (PDTC) as an antitumor agent in vivo. PDTC administration inhibited the increase of soluble IL-2R and improved mouse survival, suggesting that this compound has potential as an anti-ATL agent. We demonstrated that ATL cells could be stably xenotransplanted into NOJ mice using primary cells. This model will be useful in the establishment of novel therapies to treat ATL.

A retrospective analysis of treatment outcomes in adult T cell leukemia/lymphoma patients with aggressive disease treated with or without allogeneic stem cell transplantation: A single-center experience.

Adult T cell leukemia/lymphoma (ATL) is an aggressive peripheral T cell neoplasm with very poor prognosis. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) has been reported as a curative treatment modality for ATL. However, there are no reports comparing chemotherapy alone with allo-HSCT in ATL. In this report, we retrospectively analyzed data for patients treated with (n = 29, median age 55 years) or without allo-HSCT (n = 37, median age 58 years) for ATL in Kagoshima University Hospital, located in one of the most endemic areas of human T cell lymphotropic leukemia virus type 1 infection. Forty patients (61%) started coordination for allo-HSCT. Ten patients (34.4%) received allo-HSCT while in complete remission (CR), whereas the others were not in CR. Twenty-five patients (86.2%) received reduced-intensity conditioning, and the others received myeloablative conditioning. With a median follow-up period for survivors of 41 months (range, 5 to 125 months), the 3-year overall survival (OS) rate from first chemotherapy for all patients (with or without allo-HSCT) was 35.2%. The 3-year OS from first chemotherapy for patients who received allo-HSCT or only chemotherapy was 44.9% and 27.7%, respectively. Univariate analyses revealed that high serum soluble IL-2 receptor (sIL-2R) levels (≥ 2000 U/mL) just before the conditioning regimen and progressive disease (PD) status at HSCT (according to Japan Clinical Oncology Group Study 0907 criteria) were significant risk factors for OS in the allo-HSCT group. Multivariate analyses revealed that PD status was a significant risk factor for OS in the allo-HSCT group. In the chemotherapy-only group, the 3-year OS rate was 61.5% (95% CI, 30.8% to 81.8%) in patients with serum sIL-2R levels < 2000 U/mL for > 3 months. In contrast, the 3-year OS rate was 5.7% (95% CI, .4% to 22.4%) in patients who did not achieve serum sIL-2R levels < 2000 U/mL for >3 months. Our single-center cohort experience indicates that chemosensitivity is the most important prognostic factor for OS in ATL patients and the use of allo-HSCT is limited in chemorefractory patients with aggressive ATL disease. In the chemosensitive patients, allo-HSCT demonstrated a tendency toward better OS. Further clinical studies are warranted to determine optimal treatments for patients who are less sensitive to conventional chemotherapy.

Somatic RHOA mutation in angioimmunoblastic T cell lymphoma.

Angioimmunoblastic T cell lymphoma (AITL) is a distinct subtype of peripheral T cell lymphoma characterized by generalized lymphadenopathy and frequent autoimmune-like manifestations. Although frequent mutations in TET2, IDH2 and DNMT3A, which are common to various hematologic malignancies, have been identified in AITL, the molecular pathogenesis specific to this lymphoma subtype is unknown. Here we report somatic RHOA mutations encoding a p.Gly17Val alteration in 68% of AITL samples. Remarkably, all cases with the mutation encoding p.Gly17Val also had TET2 mutations. The RHOA mutation encoding p.Gly17Val was specifically identified in tumor cells, whereas TET2 mutations were found in both tumor cells and non-tumor hematopoietic cells. RHOA encodes a small GTPase that regulates diverse biological processes. We demonstrated that the Gly17Val RHOA mutant did not bind GTP and also inhibited wild-type RHOA function. Our findings suggest that impaired RHOA function in cooperation with preceding loss of TET2 function contributes to AITL-specific pathogenesis.

Identification of unbalanced genome copy number abnormalities in patients with multiple myeloma by single-nucleotide polymorphism genotyping microarray analysis.

Single-nucleotide polymorphism genotyping microarray (SNP array) analysis provides detailed information on chromosomal copy number aberrations. To obtain detailed information on genomic abnormalities related to pathogenesis or prognosis of multiple myeloma (MM), we performed 250K SNP array analysis in 39 MM patients and 11 cell lines. We identified an accumulation of deletions and uniparental disomies at 22q12.1. Among the hyperdiploid MM cases, chromosomal imbalance at this locus was associated with poor prognosis. On sequencing, we also found a mutation in the seizure-related 6 homolog (mouse)-like (SEZ6L) gene located at ch.22q12.1 in an MM cell line, NOP1. We further found isolated deletions in 17 genes, five of which are known tumor suppressor genes. Of these, deletion of protein tyrosine phosphatase, receptor type D (PTPRD) was found in three samples, including two patients. Consistent with previous reports, non-hyperdiploid MM, deletion of 13q (del13q) and gain of 1q in non-hyperdiploid MMs were predictive of poor prognosis (p = 0.039, p = 0.049, and p = 0.013, respectively). However, our analysis revealed that unless accompanied by gain of 1q, the prognosis of non-hyperdiploid MM was as good as that of hyperdiploid MM. Thus, SNP array analysis provides significant information useful to understanding the pathogenesis and prognosis of MM.

Relapse of Acute Myeloid Leukemia with t(16;21)(p11;q22) Mimicking Autoimmune Pancreatitis after Second Allogeneic Bone Marrow Transplantation.

We report the case of a 37-year-old woman who had a relapse of acute myeloid leukemia (AML) during treatment for chronic graft versus host disease (cGVHD) after allogeneic bone marrow transplantation. She was originally suspected of having autoimmune pancreatitis. Relapse of AML often occurs at extramedullary sites. Whereas the pancreas is rare as an organ of AML relapse, physicians should be aware that enlargement of the pancreas could be a sign of relapsed AML when excluding autoimmune pancreatitis, particularly during active cGVHD after allogeneic stem cell transplantation.

Reduction of human T-cell leukemia virus type-1 infection in mice lacking nuclear factor-kappaB-inducing kinase.

Human T-cell lymphotropic virus type 1 (HTLV-1) causes adult T-cell leukemia and inflammatory disorders. Aberrant activation of nuclear factor-kappaB (NF-kappaB) has been linked to HTLV-1 pathogenesis and to various kinds of cancers, including adult T-cell leukemia. NF-kappaB-inducing kinase (NIK) is critical for non-canonical activation of NF-kappaB and for the development of lymphoid organs. HTLV-1 activates NF-kappaB by the non-canonical pathway, but examination of the role of NIK in proliferation of HTLV-1-infected cells in vivo has been hindered by lack of a suitable animal model. Alymphoplasia (aly/aly) mice bear a mutation of NIK, resulting in defects in the development of lymphoid organs and severe deficiencies in both humoral and cell-mediated immunity. In the present study we therefore used a mouse model of HTLV-1 infection with aly/aly mice. The number of HTLV-1-infected cells in the reservoir organs in aly/aly mice was significantly smaller than in the control group 1 month after infection. In addition, aly/aly mice did not maintain provirus for 1 year and antibodies against HTLV-1 were undetectable. These results demonstrate that the absence of functional NIK impairs primary HTLV-1 proliferation and abolishes the maintenance of provirus. Interestingly, clonal proliferation of HTLV-1-infected mouse cells was not detected in aly/aly mice, which is consistent with the lack of HTLV-1 persistence. These observations imply that the clonal proliferation of HTLV-1-infected cells in secondary lymphoid organs might be important for HTLV-1 persistence.