Hematopoietic Cell Transplantation Rescues Inflammatory Bowel Disease and Dysbiosis of Gut Microbiota in XIAP Deficiency.

BACKGROUND: X-linked inhibitor of apoptosis protein (XIAP) deficiency is an infrequent inborn error of immunity that is often associated with refractory inflammatory bowel disease (IBD). The natural course of XIAP deficiency is typically associated with poor prognosis, and hematopoietic cell transplantation (HCT) is the only curative treatment. OBJECTIVE: To study (1) the effect of HCT on patients with XIAP deficiency undergoing HCT, (2) the status of XIAP deficiency-associated IBD after HCT, and (3) the gut microbiota of XIAP deficiency-associated IBD before and after HCT. METHODS: A nationwide survey of patients with XIAP deficiency was conducted. A spreadsheet questionnaire was collected from the physicians. Feces samples collected from the patients before and after HCT and their healthy family members were analyzed. RESULTS: Twenty-six patients with XIAP deficiency underwent HCT by the end of March 2020, and 22 patients (84.6%) survived. All the survivors underwent a fludarabine-based reduced-intensity condition regimen. Acute graft-versus-host disease was observed in 17 patients (65.4%). Nineteen patients experienced refractory IBD before undergoing HCT. IBD improved remarkably after HCT. After HCT, the colonoscopic and pathological symptoms were restored to normal, and the pediatric ulcerative colitis activity index improved significantly. Gut microbiota indicated dysbiosis before HCT; however, it was improved to resemble that of the healthy family members after HCT. CONCLUSIONS: This study revealed that HCT has a favorable outcome for XIAP deficiency. HCT rescues gut inflammation and dysbiosis in patients with XIAP deficiency.

[Prognostic significance of chimeric fusion gene analysis in pediatric acute megakaryoblastic leukemia].

Acute megakaryoblastic leukemia in children without Down syndrome (non-DS AMKL) is considered to be a poor prognostic subtype in acute myeloid leukemia. Recently, some chimeric fusion genes were found in pediatric non-DS AMKL; therefore, we attempted to detect chimeric fusion genes RBM15-MKL1, CBFA2T3-GLIS2, and NUP98-KDM5A from 10 pediatric non-DS AMKL diagnostic samples using polymerase chain reaction and Sanger sequencing methods. Two samples were positive for RBM15-MKL1, four had CBFA2T3-GLIS2, and only one case had NUP98-KDM5A. Both RBM15-MKL1-positive patients showed long-term remission after chemotherapy. The eight RBM15-MKL1-negative patients received hematopoietic stem cell transplantation (HSCT). In four CBFA2T3-GLIS2-positive patients, three had HSCT without complete remission and two of themdied. Additional treatment stratification depending on chimeric fusion genes and development of new therapeutic drugs are required for non-DS AMKL.

High rates of ovarian function preservation after hematopoietic cell transplantation with melphalan-based reduced intensity conditioning for pediatric acute leukemia: an analysis from the Japan Association of Childhood Leukemia Study (JACLS).

Women are at high risk of hypergonadotropic hypogonadism after hematopoietic cell transplantation (HCT). Hypogonadism is universal after irradiation or busulfan. We hypothesized that reduced intensity conditioning (RIC) might protect ovarian function after HCT. We retrospectively reviewed data from patients with acute leukemia treated according to the Japan Association of Childhood Leukemia Study and nationwide multicenter study protocol. We selected 11 female patients with acute leukemia who received first HCT with RIC, had survived for three or more years after HCT, and were aged ≥ 12 years at the last follow-up visit. Median age at diagnosis, HCT, and last visit were 8, 10, and 17 years. Six patients received HLA-matched bone marrow (BM), two HLA-mismatched BM, and three cord blood. Melphalan was used as conditioning regimen in all patients. At the last visit, six of seven post-pubertal patients at transplantation recovered menstruation, and four of four patients who underwent transplantation at the pre-pubertal began menstruation. Height z scores showed no significant reduction between pre-transplant and post-transplant. No patients received growth hormone treatment. Only one recipient displayed subclinical hypothyroidism. Melphalan-based RIC may be an encouraging option for patients with acute leukemia to avoid ovarian and endocrine dysfunction after HCT.

Sequential use of second-generation tyrosine kinase inhibitors following imatinib therapy in pediatric chronic myeloid leukemia: A report from the Japanese Pediatric Leukemia/Lymphoma Study Group.

BACKGROUND: The details of the sequential use of imatinib for first-line treatment followed by second-generation tyrosine kinase inhibitors (2G-TKIs) for pediatric chronic myeloid leukemia (CML) are still unknown. This study analyzed clinical responses and adverse effects of the use of 2G-TKIs following imatinib in pediatric chronic phase (CP)-CML. PROCEDURES: The Japanese Pediatric Leukemia/Lymphoma Study Group conducted a retrospective study of patients with newly diagnosed CML from 1996 to 2011. A total of 152 cases that received imatinib as first-line therapy were analyzed. RESULTS: Excluding 46 cases treated with hematopoietic stem cell transplantation before nilotinib and dasatinib became available, 31 of 106 patients changed to 2G-TKIs. The primary reason for changing from imatinib was poor response, followed by intolerance, with the main reason for the latter being musculoskeletal events. Switches from imatinib to 2G-TKIs with intolerance occurred significantly earlier than switches with poor response. Sixteen and 15 patients were treated with nilotinib and dasatinib, respectively, following imatinib therapy. After switching to 2G-TKIs, the response status improved in 63% of evaluable patients. The adverse effect profiles of nilotinib and dasatinib tended to be different, with hyperbilirubinemia observed in 33% of nilotinib-treated patients, but in none of the cases with dasatinib. CONCLUSION: This retrospective study represents the first series of children and adolescents in whom sequential use of imatinib followed by 2G-TKIs was reported. These data provide useful insights into the selection of 2G-TKIs as first-line treatment for children and adolescents with CP-CML.

Recurrent RARB Translocations in Acute Promyelocytic Leukemia Lacking RARA Translocation.

Translocations of retinoic acid receptor-α (RARA), typically PML-RARA, are a genetic hallmark of acute promyelocytic leukemia (APL). However, because a small fraction of APL lack translocations of RARA, we focused here on APL cases without RARA translocation to elucidate the molecular etiology of RARA-negative APL. We performed whole-genome sequencing, PCR, and FISH for five APL cases without RARA translocations. Four of five RARA-negative APL cases had translocations involving retinoic acid receptor-ß (RARB) translocations, and TBL1XR1-RARB was identified as an in-frame fusion in three cases; one case had an RARB rearrangement detected by FISH, although the partner gene could not be identified. When transduced in cell lines, TBL1XR1-RARB homodimerized and diminished transcriptional activity for the retinoic acid receptor pathway in a dominant-negative manner. TBL1XR1-RARB enhanced the replating capacity of mouse bone marrow cells and inhibited myeloid maturation of human cord blood cells as PML-RARA did. However, the response of APL with RARB translocation to retinoids was attenuated compared with that of PML-RARA, an observation in line with the clinical resistance of RARB-positive APL to ATRA. Our results demonstrate that the majority of RARA-negative APL have RARB translocations, thereby forming a novel, distinct subgroup of APL. TBL1XR1-RARB as an oncogenic protein exerts effects similar to those of PML-RARA, underpinning the importance of retinoic acid pathway alterations in the pathogenesis of APL.Significance: These findings report a novel and distinct genetic subtype of acute promyelocytic leukemia (APL) by illustrating that the majority of APL without RARA translocations harbor RARB translocations. Cancer Res; 78(16); 4452-8. ©2018 AACR.

Azacitidine successfully maintained the second remission in an infant with KMT2A-rearranged acute lymphoblastic leukemia who relapsed after unrelated cord blood transplantation.

The outcome for infants with KMT2A (MLL)-rearranged acute lymphoblastic leukemia (MLL-r ALL) is dismal despite intensive therapy, including hematopoietic stem cell transplantation (HSCT). Epigenetic dysregulation is considered a key driver of MLL-r leukemogenesis, which theoretically supports the use of epigenetic modifiers as a treatment option. We report an infant MLL-r ALL case with post-HSCT relapse. After achieving a second remission, which was maintained for 10 months using only the DNA methyltransferase inhibitor, azacitidine, the patient successfully received the second HSCT. This report describes the clinical effectiveness of azacitidine for the treatment of infant MLL-r ALL.

Flow cytometric analysis as an additional predictive tool of treatment response in children with chronic-phase chronic myeloid leukemia treated with imatinib.

Bone marrow samples of newly diagnosed children with chronic-phase chronic myeloid leukemia (CML) were obtained at diagnosis and after imatinib initiation and stained with anti-human CD34, CD38, CD123, CD45RA, cMpl, and lineage antibodies. Flow cytometric analysis revealed that granulocyte macrophage progenitor predominance in CML progenitors at diagnosis and elevated cMpl expression in bone marrow progenitors at 3 months may predict poor outcome in children with chronic-phase CML treated with imatinib. We recommend flow cytometric analysis of bone marrow in the early phase of treatment, as it is a convenient tool that may predict treatment response and guide CML management.

Hematopoietic Stem Cell Transplantation for XIAP Deficiency in Japan.

BACKGROUND: X-linked inhibitor of apoptosis protein (XIAP) deficiency is a rare immunodeficiency that is characterized by recurrent hemophagocytic lymphohistiocytosis (HLH) and splenomegaly and sometimes associated with refractory inflammatory bowel disease (IBD). Although hematopoietic stem cell transplantation (HSCT) is the only curative therapy, the outcomes of HSCT for XIAP deficiency remain unsatisfactory compared with those for SLAM-associated protein deficiency and familial HLH. AIM: To investigate the outcomes and adverse events of HSCT for patients with XIAP deficiency, a national survey was conducted. METHODS: A spreadsheet questionnaire was sent to physicians who had provided HSCT treatment for patients with XIAP deficiency in Japan. RESULTS: Up to the end of September 2016, 10 patients with XIAP deficiency had undergone HSCT in Japan, 9 of whom (90%) had survived. All surviving patients had received a fludarabine-based reduced intensity conditioning (RIC) regimen. Although 5 patients developed post-HSCT HLH, 4 of them survived after etoposide administration. In addition, the IBD associated with XIAP deficiency improved remarkably after HSCT in all affected cases. CONCLUSION: The RIC regimen and HLH control might be important factors for successful HSCT outcomes, with improved IBD, in patients with XIAP deficiency.

Role of Second Transplantation for Children With Acute Myeloid Leukemia Following Posttransplantation Relapse.

BACKGROUND: In children with acute myeloid leukemia (AML), hematopoietic stem cell transplantation (HSCT) in first remission is indicated for patients with a relatively high risk of relapse. Second HSCT is a curative option; however, few reports have been published about a second HSCT in children for AML with posttransplantation relapse. PROCEDURE: Using the database provided by the Japanese Society of Hematopoietic Cell Transplantation, we analyzed 46 children with AML who underwent a second allogeneic HSCT after achieving a second remission. RESULTS: The median duration from the first to second HSCT was 20 months, and the source of the second HSCT was related bone marrow (BM) in 22, related peripheral blood in 6, unrelated BM in 14, and unrelated cord blood in 4 patients. Twenty-five children eventually died of the following causes: progressive disease in 14 and transplant-related toxicities in 9. The 5-year overall survival rate was 41.7 ± 7.7%. An interval of less than 24 months between the first and second HSCT was a significant poor prognostic factor. CONCLUSIONS: Children with AML who experience a relapse after HSCT in first remission have a good chance of survival with a second HSCT if a second remission is achieved.

Comparison of chemotherapeutic agents as a myeloablative conditioning with total body irradiation for pediatric acute lymphoblastic leukemia: A study from the pediatric ALL working group of the Japan Society for Hematopoietic Cell Transplantation.

BACKGROUND: As a partner of total body irradiation (TBI) in hematopoietic stem cell transplantation (HSCT) for pediatric acute lymphoblastic leukemia (ALL), various cytotoxic agents are used, but the optimal combination is still unclear. PROCEDURE: We retrospectively analyzed 767 children who received TBI-based myeloablative allogeneic HSCT in complete remission (CR), using nationwide registry data of the Japan Society for Hematopoietic Cell Transplantation. Combinations of chemotherapy were categorized as follows: cyclophosphamide (CY) (n = 74), melphalan (L-PAM) (n = 139), CY + etoposide (VP16) (n = 408), CY + cytarabine (AraC) (n = 73), and others (n = 73). RESULTS: Event-free survival (EFS) at 5 years after HSCT was 62.2% for CY, 71.4% for L-PAM, 67.6% for CY + VP16, 52.6% for CY + AraC, and 59.1% for others (P = 0.009). Further detailed comparison of LPAM and CY + VP16 demonstrated superior EFS for LPAM (83.2 ± 6.7%), with a marked difference compared with CY + VP16 (66.7 ± 4.9%) when limited to HSCT from a matched related donor (MRD), and this result was reproduced regardless of disease status (CR1 or CR2). However, EFS for CY + VP16 (68.3 ± 2.8%) was comparable to that for LPAM (64.5 ± 5.7%, P = 0.37) in HSCT from alternative donors, because higher non-relapse mortality attenuated the advantage of LPAM. CONCLUSIONS: For pediatric ALL in remission, LPAM could provide superior EFS for HSCT from MRD; however, compared to LPAM, CY + VP16 has similar EFS for HSCT from an alternative donor.

Outcome of children with relapsed acute myeloid leukemia following initial therapy under the AML99 protocol.

The outcomes of children with relapsed acute myeloid leukemia (AML) are known to be poor, but remain obscure. We retrospectively analyzed 71 patients who had relapsed following first-line treatment under the AML99 protocol. We investigated the time and site of recurrence, response to re-induction therapy, and performance of hematopoietic stem cell transplantation (HSCT) in relapsed cases, and performed a multivariate analysis to identify prognostic factors. The 5-year overall-survival (OS) rate after relapse was 37 %. Of 71 patients, three died without any anti-leukemic therapy and two underwent allogeneic HSCT. The remaining 66 patients received re-induction chemotherapy, and 33 (50 %) achieved second CR (CR2). Twenty-two of 25 (88 %) late relapse patients and 11 of 41 (27 %) early relapse patients achieved CR2 (P < 0.001). Twenty-nine CR2 cases and 35 non-CR2 cases underwent allogeneic HSCT. The 5-year OS rate was significantly higher in patients who underwent HSCT in CR2 than those in non-CR2 (66 vs. 17 %, P < 0.000001). Multivariate analysis indicated that early relapse (P < 0.05) and the positivity of the FMS-like tyrosine kinase 3--internal tandem duplication (P < 0.05) were adverse prognostic factors for survival. In conclusion, the etiology of relapsed pediatric AML needs to be elucidated and effective chemotherapy should be administered to obtain CR2.

Detection of RBM15-MKL1 fusion was useful for diagnosis and monitoring of minimal residual disease in infant acute megakaryoblastic leukemia.

Acute megakaryocytic leukemia (AMKL) with t(1;22)(p13;q13) is a distinct category of myeloid leukemia by WHO classification and mainly reported in infants and young children. Accurate diagnosis of this type of AMKL can be difficult, because a subset of patients have a bone marrow (BM) blast percentage of less than 20% due to BM fibrosis. Therefore, it is possible that past studies have underestimated this type of AMKL. We present here the case of a 4-month-old female AMKL patient who was diagnosed by presence of the RBM15-MKL1 (OTT-MAL) fusion transcript by RT-PCR. In addition, we monitored RBM15-MKL1 fusion at several time points as a marker of minimal residual disease (MRD), and found that it was continuously negative after the first induction chemotherapy even by nested RT-PCR. Detection of the RBM15-MKL1 fusion transcript thus seems to be useful for accurate diagnosis of AMKL with t(1;22)(p13;q13). We recommend that the RBM15-MKL1 fusion transcript be analyzed for all suspected AMKL in infants and young children. Furthermore, monitoring of MRD using this fusion transcript would be useful in treatment of AMKL with t(1;22)(p13;q13).

Sustained elevation of serum interleukin-18 and its association with hemophagocytic lymphohistiocytosis in XIAP deficiency.

X-linked lymphoproliferative syndrome (XLP) is a rare primary immunodeficiency characterized by increased vulnerability to Epstein-Barr virus infection. XLP type 1 is caused by mutations in SH2D1A, whereas X-linked inhibitor of apoptosis (XIAP) encoded by XIAP/BIRC4 is mutated in XLP type 2. In XIAP deficiency, hemophagocytic lymphohistiocytosis (HLH) occurs more frequently and recurrence is common. However, the underlying mechanisms remain mostly unknown. We describe the characteristics of the cytokine profiles of serum samples from 10 XIAP-deficient patients. The concentration of interleukin (IL)-18 was strikingly elevated in the patients presented with HLH, and remained high after the recovery from HLH although levels of other pro-inflammatory cytokines approached the normal range. Longitudinal examination of two patients demonstrated marked exacerbation of IL-18 levels during every occasion of HLH. These findings may suggest the association between HLH susceptibility and high serum IL-18 levels in XIAP deficiency.

Immunosuppressive therapy with horse anti-thymocyte globulin and cyclosporine as treatment for fulminant aplastic anemia in children.

Patients with severe aplastic anemia (SAA) and an absolute neutrophil count (ANC) of 0 typically have fatal outcomes. We defined fulminant AA (FAA) as ANC = 0 for at least 2 weeks prior to and after immunosuppressive therapy (IST). We analyzed the outcomes of 35 children with FAA among 288 children who enrolled in a prospective study for AA (AA-97 study). AA was classified as FAA (n = 35), very SAA (vSAA; n = 129), or SAA (n = 124). All of the children received the IST with horse anti-thymocyte globulin (ATG) and cyclosporine (CsA). A significantly lower response rate at 6 months was seen in children with FAA when compared to those with vSAA or SAA (40.0, 63.6, and 63.7 %, respectively; p = 0.027). Of 20 nonresponder patients in the FAA group, 11 were rescued by alternative donor transplantation, and 5 patients showed a late response after 6 months. Consequently, no significant difference was noted in overall survival when comparing the FAA, vSAA, and SAA groups (88.5, 95.8, and 96.8 %). These findings indicate that IST with ATG and CsA is justified as a first-line treatment for children with FAA who lack a human leukocyte antigen-matched sibling donor.

Allogeneic hematopoietic cell transplantation for XIAP deficiency: an international survey reveals poor outcomes.

There have been no studies on patient outcome after allogeneic hematopoietic cell transplantation (HCT) in patients with X-linked inhibitor of apoptosis (XIAP) deficiency. To estimate the success of HCT, we conducted an international survey of transplantation outcomes. Data were reported for 19 patients. Seven patients received busulfan-containing myeloablative conditioning (MAC) regimens. Eleven patients underwent reduced intensity conditioning (RIC) regimens predominantly consisting of alemtuzumab, fludarabine, and melphalan. One patient received an intermediate-intensity regimen. Survival was poor in the MAC group, with only 1 patient surviving (14%). Most deaths were from transplantation-related toxicities, including venoocclusive disease and pulmonary hemorrhage. Of the 11 patients who received RIC, 6 are currently surviving at a median of 570 days after HCT (55%). Preparative regimen and HLH activity affected outcomes, and of RIC patients reported to be in remission from HLH, survival is 86% (P = .03). We conclude that MAC regimens should not be used for patients with XIAP deficiency. It is possible that the loss of XIAP and its antiapoptotic functions contributes to the high incidence of toxicities observed with MAC regimens. RIC regimens should be pursued with caution and, if possible, efforts should be made to ensure HLH remission before HCT in these patients.

Outcome of children with refractory anaemia with excess of blast (RAEB) and RAEB in transformation (RAEB-T) in the Japanese MDS99 study.

We report the outcome of 16 children with refractory anaemia with excess of blasts (RAEB; n = 4) and RAEB in transformation (RAEB-T; n = 12) following induction therapy with etoposide, cytarabine and mitoxantrone (ECM) prior to haematopoietic stem cell transplantation (HSCT). The median observation period was 77 months (range 5-123). Complete remission rate was 81% following induction; no toxic deaths occurred. Eight-year event-free survival and overall survival was 50% and 56%, respectively. None of the three patients with a complex karyotype survived, suggesting karyotype is a crucial prognostic factor for survival. This study indicates the safety and high remission rate of ECM and high survival rates after HSCT for paediatric RAEB and RAEB-T.

Clinical features and outcome of X-linked lymphoproliferative syndrome type 1 (SAP deficiency) in Japan identified by the combination of flow cytometric assay and genetic analysis.

OBJECTIVE: X-linked lymphoproliferative syndrome (XLP) type 1 is a rare immunodeficiency, which is caused by mutations in SH2D1A gene. The prognosis of XLP is very poor, and hematopoietic stem cell transplantation (HSCT) is the only curative therapy. We characterized the clinical features and outcome of Japanese patients with XLP-1. METHODS: We used a combination of flow cytometric analysis and genetic analysis to identify XLP-1 and reviewed the patient characteristics and survival with HSCT. RESULTS: We identified 33 patients from 21 families with XLP-1 in Japan. Twenty-one of the patients (65%) who did not undergo a transplant died of the disease and complications. Twelve patients underwent HSCT, and 11 of these (92%) survived. CONCLUSION: We described the clinical characteristics and outcomes of Japanese patients with XLP-1, and HSCT was the only curative therapy for XLP-1. The rapid and accurate diagnosis of XLP with the combination of flow cytometric assay and genetic analysis is important.

Clinical and genetic characteristics of XIAP deficiency in Japan.

Deficiency of X-linked inhibitor of apoptosis (XIAP) caused by XIAP/BIRC4 gene mutations is an inherited immune defect recognized as X-linked lymphoproliferative syndrome type 2. This disease is mainly observed in patients with hemophagocytic lymphohistiocytosis (HLH) often associated with Epstein-Barr virus infection. We described nine Japanese patients from six unrelated families with XIAP deficiency and studied XIAP protein expression, XIAP gene analysis, invariant natural killer T (iNKT) cell counts, and the cytotoxic activity of CD8(+) alloantigen-specific cytotoxic T lymphocytes. Of the nine patients, eight patients presented with symptoms in infancy or early childhood. Five patients presented with recurrent HLH, one of whom had severe HLH and died after cord blood transplantation. One patient presented with colitis, as did another patient's maternal uncle, who died of colitis at 4 years of age prior to diagnosis with XIAP deficiency. Interestingly, a 17-year-old patient was asymptomatic, while his younger brother suffered from recurrent HLH and EBV infection. Seven out of eight patients showed decreased XIAP protein expression. iNKT cells from patients with XIAP deficiency were significantly decreased as compared with age-matched healthy controls. These results in our Japanese cohort are compatible with previous studies, confirming the clinical characteristics of XIAP deficiency.

Empty sella/pituitary atrophy and endocrine impairments as a consequence of radiation and chemotherapy in long-term survivors of childhood leukemia.

Radiation-induced empty sella (ES) or pituitary atrophy/small pituitary and endocrine impairments, including pituitary and gonadal dysfunction, can manifest decades after radiation and chemotherapy in childhood-onset leukemia patients who received prophylactic cranial irradiation or total body irradiation in preparation for bone marrow transplant. Six childhood-onset leukemia patients (age at diagnosis of leukemia; 2.7-10.2 years) participated in this study. Magnetic resonance imaging (MRI) of the pituitary gland and endocrinological studies were performed 10.5-32.1 years after cranial irradiation. In four of the six patients examined, ES or pituitary atrophy was detected approximately 10.5-19.8 years after cranial irradiation. Four patients had hypogonadism (primary, 3; hypothalamic-pituitary, 1) and one had primary hypothyroidism. We conclude that ES or pituitary atrophy and endocrine impairments can manifest decades after radiation and chemotherapy in childhood-onset leukemia. These patients should, therefore, undergo regular follow-up, including pituitary MRI and hormonal examinations.