Identification of a unique subset of tissue-resident memory CD4+ T cells in Crohn's disease.

T cells differentiate into highly diverse subsets and display plasticity depending on the environment. Although lymphocytes are key mediators of inflammation, functional specialization of T cells in inflammatory bowel disease (IBD) has not been effectively described. Here, we performed deep profiling of T cells in the intestinal mucosa of IBD and identified a CD4+ tissue-resident memory T cell (Trm) subset that is increased in Crohn's disease (CD) showing unique inflammatory properties. Functionally and transcriptionally distinct CD4+ Trm subsets are observed in the inflamed gut mucosa, among which a CD-specific CD4+ Trm subset, expressing CD161 and CCR5 along with CD103, displays previously unrecognized pleiotropic signatures of innate and effector activities. These inflammatory features are further enhanced by their spatial proximity to gut epithelial cells. Furthermore, the CD-specific CD4+ Trm subset is the most predominant producer of type 1 inflammatory cytokines upon various stimulations among all CD4+ T cells, suggesting that the accumulation of this T cell subset is a pathological hallmark of CD. Our results provide comprehensive insights into the pathogenesis of IBD, paving the way for decoding of the molecular mechanisms underlying this disease.

Co-occurrence of hypertrophic cardiomyopathy and juvenile myelomonocytic leukemia in a neonate with Noonan syndrome, leading to premature death.

We report a case of a neonate with Noonan syndrome presenting with concurrent hypertrophic cardiomyopathy and juvenile myelomonocytic leukemia, which resulted in premature death. Cases with Noonan syndrome diagnosed during the neonatal period might not necessarily show mild clinical course, and premature death is a possible outcome to be considered.

Low-dose azacitidine maintenance therapy after allogeneic stem cell transplantation for high-risk pediatric acute myeloid leukemia.

The dismal prognosis of pediatric acute myeloid leukemia (AML) relapsing after hematopoietic stem cell transplantation (HSCT) requires exploration of novel strategies to prevent relapse. Azacitidine (AZA) maintenance therapy could potentially reduce the recurrence rate post HSCT. Here, we presents the cases of three children with high-risk AML post HSCT who were treated with low-dose AZA maintenance therapy, demonstrating the feasibility of this therapy. Currently, all three are in complete remission for 13-41 months despite their high-risk characteristics. Our encouraging data warrant larger prospective studies to assess the efficacy and safety of low-dose AZA maintenance therapy post HSCT for pediatric patients with high-risk AML.

ETV6-ABL1 fusion combined with monosomy 7 in childhood B-precursor acute lymphoblastic leukemia.

ETV6-ABL1 fusion is a rare but recurrent oncogenic lesion found in childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL), without an established chromosomal abnormality, and is associated with poor outcome. In ETV6-ABL1-positive cases, an in-frame fusion produced by a complex rearrangement results in constitutive chimeric tyrosine kinase activity. Monosomy 7 is also a rare and unfavorable chromosomal abnormality in childhood BCP-ALL. Here, we report a 14-year-old female BCP-ALL patient with ETV6-ABL1 fusion combined with monosomy 7. She was admitted to our hospital because of persistent fever. Bone marrow nuclear cell count on admission was 855,000/µL with 90.0% blastic cells of lymphoid morphology. Blasts were positive for CD10, CD19, CD20, CD34, cyCD79a, cyTdT, HLA-DR, and CD66c, had a karyotype of 45, XX, - 7 [18/20] and a split signal for ABL1 FISH probe (92.7%), and were sensitive to tyrosine kinase inhibitors, imatinib and dasatinib, in vitro. ETV6-ABL1 fusion transcript was identified by whole transcriptome sequencing and confirmed by RT-PCR. She was treated with the high-risk protocol based on ALL-BFM 95, achieved complete remission (CR) after induction chemotherapy, and maintained CR for 4 months. To our knowledge, this is the first report of ETV6-ABL1 fusion combined with monosomy 7 in childhood BCP-ALL.

Successful Treatment of Transplantation-associated Atypical Hemolytic Uremic Syndrome With Eculizumab.

We herein reported a 4-month-old boy with transplantation-associated atypical hemolytic uremic syndrome (TA-aHUS) who was successfully treated with eculizumab. The patient diagnosed with type 3 of familial hemophagocytic lymphohistiocytosis underwent cord blood transplantation. After transplantation, he developed TA-aHUS, but plasma exchanges were unsuccessful. We identified deletions in CFH-related gene 1 (del-CFHR1) by the multiplex ligation-dependent probe amplification testing procedure and CFH autoantibodies. Eculizumab has been administered to the patient, with a marked improvement being achieved in thrombocytopenia. He has been well except for the persistent microhematuria for a year after transplantation. Uncontrolled complement activation might be involved in the pathophysiology of TA-aHUS.

Reemergence of translocation t(11;19)(q23;p13.1) in the absence of clinically overt leukemia.

We report the case of a 10-year-old female with acute myeloid leukemia (AML) FAB M0 carrying a novel t(11;19)(q23;p13.1) MLL-ELL variant, in which intron 8 of MLL is fused to exon 6 of ELL. Complete remission, judged by morphology and cytogenetic analysis, was achieved after the conventional chemotherapy. Eight months after completion of therapy, the level of WT-1 in peripheral blood and the number of cells with the MLL-ELL fusion transcript resurged. However, the patient remained overtly healthy and the morphology in the bone-marrow smear was innocuous, with no sign of relapse or secondary leukemia. Without any evidence of relapse, the patient has been closely observed without any therapeutic intervention. For approximately 2 years after the completion of therapy, despite clonal proliferation of pre-leukemic cells with an MLL-ELL fusion gene, she has maintained complete remission. In this case, the rare variant form of MLL-ELL fusion that has been identified may be related to diminished leukemogenic capacity, resulting in the persistence of pre-leukemic status; an additional genetic abnormality may thus be necessary for full transformation of pre-leukemic cells.

Congenital immature pure erythroid leukemia with E-cadherin expression.

Congenital pure erythroid leukemia is exceedingly rare and poses a diagnostic challenge. We report an atypical case of congenital pure erythroid leukemia that did not express typical erythroid markers. The patient presented with a high white blood cell count with blastic cells at birth. Although flow cytometric analyses of peripheral blood and bone marrow showed a large CD45-negative cell population, we did not identify any evidence of monoclonality. While the circulating blasts decreased with only supportive care, hepatomegaly with multiple nodules was accompanied by liver failure, disseminated intravascular coagulation, and development of hemophagocytic lymphohistiocytosis. Pathological examination of the liver biopsy specimen revealed a small round cell tumor that was negative for nearly all hematopoietic cell markers, including classical erythroid cell markers, and positive for CD43, CD71, and E-cadherin, an early erythroid marker epithelial calcium-dependent adhesion protein, suggesting that these tumor cells originated from an immature erythroblast. We found high ß-catenin and c-Myc protein expression, which were not previously described in pure erythroid leukemia. Cytosine arabinoside temporarily alleviated clinical symptoms; however, the patient died of progressive disease at 8 months of age. This case indicates that E-cadherin is useful for diagnosing pure erythroid leukemia, even in immature cases.

Refractory double-hit lymphoma/leukemia in childhood mimicking B-precursor acute lymphoblastic leukemia at initial presentation.

A 10-year-old girl was referred to our hospital with left preauricular adenopathy and gingival swelling. She was diagnosed with B-cell precursor acute lymphoblastic leukemia (BCP-ALL) based on being positive for expressions of CD10, CD19, TdT and HLA-DR. She showed no CD20 expression at the time of diagnosis. Based on the initial diagnosis of BCP-ALL, induction chemotherapy for BCP-ALL was initiated. However, the blasts did not disappear from her peripheral blood. Bone marrow examination on day 33 identified 81.3% residual blasts with positive expressions of CD19, 20 and HLA-DR and negative CD10 and TdT expressions; these cells were morphologically and phenotypically different from those at the initial diagnosis. Based on cytogenetic studies, the final diagnosis was double-hit lymphoma/leukemia (DHL) with IgH-BCL2 and Igλ-MYC. Although dose intensive chemotherapy, including rituximab, led to complete remission, bone marrow and central nervous system relapse occurred. At relapse, blasts expressed CD10, CD19 and HLA-DR, but not CD20, findings the same as those at the onset. The patient died of the disease 44 days after cord blood transplantation with non-remission status. DHL in childhood is extremely rare and its prognosis is poor. The establishment of an effective treatment for DHL is highly anticipated.

Clinically Mild Encephalitis/Encephalopathy With a Reversible Splenial Lesion Accompanied by Epstein-Barr Virus Hemophagocytic Lymphohistiocytosis: A Case Report and Review of the Literature.

Central nervous system involvement in hemophagocytic lymphohistiocytosis (HLH) is associated with a poor outcome. For such patients, it is unknown whether more aggressive therapies, such as intrathecal methotrexate or hydrocortisone, are inevitably required. We present a very rare case of 3-year-old Japanese girl who developed mild encephalitis/encephalopathy with a reversible splenial lesion, accompanied by Epstein-Barr virus-associated HLH, and review previous similar reports. Our case and previous reports suggest that mild encephalitis/encephalopathy with a reversible splenial lesion accompanied by Epstein-Barr virus-associated HLH has a relatively good prognosis, even in the absence of intrathecal treatments.

Successful non-myeloablative allogenic bone marrow transplantation in a child with severe congenital neutropenia complicated by chronic pulmonary infection.

We herein describe a 2-year-old boy with severe congenital neutropenia (SCN) who was successfully treated with reduced-intensity bone marrow transplantation (HSCT). He had suffered recurrent episodes of bacterial pneumonia from 12 months of age, and was found to have severe neutropenia with white blood cell counts below 100/µl. The patient harbored a heterozygous missense mutation in ELANE exon 4 (p.Gln134Pro, NM_001972.2: c.401A>C). This was a novel mutation. Due to intractable pneumonia and severe persistent neutropenia, reduced-intensity HSCT was performed from an HLA-matched sibling donor. The preparative regimen consisted of melphalan, fludarabine, and 4 Gy of total body irradiation. Hematopoietic engraftment was rapidly obtained, i.e., by day +14, and complete donor chimerism was subsequently achieved. The lung complications observed pre-transplantation markedly improved after neutrophil recovery, i.e., by day +60. We concluded that HSCT is a useful treatment for SCN patients, especially for those at high risk of leukemic transformation. Fludarabine-based reduced-intensity HSCT may represent a safe and effective therapeutic option for patients with SCN who need HSCT even if they have intractable infectious complications.

Blood purification in fulminant hepatic failure.

Fulminant hepatic failure (FHF) can be described as a potentially fatal condition presenting with hepatic encephalopathy (HE) and coagulopathy associated with acute hepatic dysfunction, regardless of its etiology. Blood purification (BP) is expected to be effective against HE and coagulopathy in FHF. In this paper, we outline the objectives and methods of BP in the treatments of cases with FHF and indicate a concrete method for and outcomes of BP at our facility. In high-flow dialysate continuous hemodiafiltration (HFCHDF), the conventional CHDF bedside console is connected to a personal dialysis console to induce a high flow rate of dialysate. With this method, the dialysate flow rate is about 500 ml/min at maximum, equivalent to about 50 times the dialysate flow rate during ordinary CHDF. The role of plasma exchange (PE) is considered a means of replacing useful substances, such as clotting factors in fresh frozen plasma rather than a means of removing pathogenic substances. As needed, slow PE (SPE) can be incorporated by connection in series. Analysis of data from 90 patients with FHF who underwent BP at our facility after 1990 revealed that restoration of consciousness was achieved in 33 (70.2%) of 47 cases when treated with HFCHDF. This survival in the HFCHDF group was significantly higher than that in the CHDF group. Analysis of data from cases in which ammonia could be measured continuously revealed that blood ammonia level decreased over time following HFCHDF. We also revealed that HFCHDF was useful for preventing the side effects of PE, such as hypernatremia, metabolic alkalosis, and sharp decrease in colloid osmotic pressure. It is concluded that HFCHDF is useful in the treatment of HE and for preventing the side effects of PE. Therefore, we suggested that HFCHDF + SPE should be standardized for the treatment of FHF.

Efficacy of high-flow dialysate continuous hemodiafiltration in the treatment of fulminant hepatic failure.

We compared the clinical efficacy of high-flow dialysate continuous hemodiafiltration (HFCHDF) performed as artificial liver support (ALS) in fulminant hepatic failure (FHF) with those of conventional ALS techniques. Ninety patients were divided into non-HFCHDF and HFCHDF groups. Rate of recovery from coma was significantly higher in the HFCHDF group (70.2%) than in the non-HFCHDF group (44.2%) (p<0.01). The excellent recovery rate from coma achieved in patients with FHF by HFCHDF may be due to its enhanced capacity for liver support enabling efficient removal of substances causing hepatic coma from blood. HFCHDF should thus be useful for ALS.