[Sequential therapy with inotuzumab ozogamicin followed by CAR T-cell therapy for Philadelphia chromosome-negative acute lymphoblastic leukemia].

A 25-year-old woman with a history of B-cell acute lymphoblastic leukemia over ten years ago was referred to our hospital with a chief complaint of leukoblastosis. She was participating in a JPLSG (Japanese Pediatric Leukemia/Lymphoma Study Group) clinical study at that time. We diagnosed ALL relapse by multi-color flow cytometric analysis of bone marrow samples at admission, with reference to previous JPLSG data. Because her leukemic cells were resistant to conventional cytotoxic agents, she proceeded to lymphocyte apheresis for chimeric antigen receptor T-cell (CAR-T, Tisagenlecleucel [Tisa-cel]). She received two cycles of inotuzumab ozogamicin as a bridging therapy to Tisa-cel, resulting in a hematological complete remission (minimal residual disease measured by polymerase chain reaction [PCR-MRD] was positive at 1.0×10-4). She was finally administered Tisa-cel and achieved MRD negativity. She is currently in complete remission with careful MRD monitoring. This strategy of sequential bi-targeted therapy combining antibody conjugates and CAR-T cells provides tumor control in deeper remission and minimal damage to organ function through reduced use of cytotoxic anti-tumor agents. Therefore, we believe that this therapeutic strategy is an effective and rational treatment for adolescent and young adult ALL patients.

Differentiating Between Epstein-Barr Virus-positive Lymphoid Neoplasm Relapse and Post-transplant Lymphoproliferative Disorder After Sex-mismatched Hematopoietic Stem Cell Transplantation.

After allogeneic hematopoietic stem cell transplantation (HSCT), accurate differentiation between donor-derived post-transplant lymphoproliferative disorder (PTLD) and relapse of recipient-derived lymphoproliferative disorder (LPD) is crucial for determining treatment. Conventional diagnostic approaches for PTLD include histopathological examination, flow cytometry, and chimerism analysis of bulk tumor tissue. However, these methods are inconclusive in cases in which the primary disease is an Epstein-Barr virus (EBV)-positive LPD and is of the same lineage as that of the post-HSCT LPD tumor cells. Particularly, in cases where the number of tumor cells in the tissue is low, it is difficult to determine the origin of tumor cells. In this study, we developed a new method to simultaneously detect signals using sex chromosome fluorescence in situ hybridization, immunofluorescence staining, and EBV-encoded small RNA in situ hybridization on a single section of formalin-fixed paraffin-embedded histopathological specimen. The utility of the method was validated using specimens from 6 cases of EBV-positive LPD after sex-mismatched HSCT that were previously difficult to diagnose, including Hodgkin lymphoma-like PTLD that developed after HSCT for Hodgkin lymphoma and recurrence of chronic active EBV infection. This method successfully preserved the histologic structure after staining and allowed accurate determination of tumor cell origin and lineage at the single-cell level, providing a definitive diagnosis in all cases. This method provides a powerful tool for the diagnosis of LPDs after sex-mismatched HSCT.

Mutations affecting liver development and function in Medaka, Oryzias latipes, screened by multiple criteria.

We report here mutations affecting various aspects of liver development and function identified by multiple assays in a systematic mutagenesis screen in Medaka. The 22 identified recessive mutations assigned to 19 complementation groups fell into five phenotypic groups. Group 1, showing defective liver morphogenesis, comprises mutations in four genes, which may be involved in the regulation of growth or patterning of the gut endoderm. Group 2 comprises mutations in three genes that affect the laterality of the liver; in kendama mutants of this group, the laterality of the heart and liver is uncoupled and randomized. Group 3 includes mutations in three genes altering bile color, indicative of defects in hemoglobin-bilirubin metabolism and globin synthesis. Group 4 consists of mutations in three genes, characterized by a decrease in the accumulation of fluorescent metabolite of a phospholipase A(2) substrate, PED6, in the gall bladder. Lipid metabolism or the transport of lipid metabolites may be affected by these mutations. Mutations in Groups 3 and 4 may provide animal models for relevant human diseases. Group 5 mutations in six genes affect the formation of endoderm, endodermal rods and hepatic bud from which the liver develops. These Medaka mutations, identified by morphological and metabolite marker screens, should provide clues to understanding molecular mechanisms underlying formation of a functional liver.