Development of functional human blood and immune systems in NOD/SCID/IL2 receptor γ chainnull mice

Here we report that a new nonobese diabetic/severe combined immunodeficient (NOD/SCID) mouse line harboring a complete null mutation of the common cytokine receptor γ chain (NOD/SCID/interleukin 2 receptor [IL2r] γnull) efficiently supports development of functional human hemato-lymphopoiesis. Purified human (h) CD34+ or hCD34+hCD38– cord blood (CB) cells were transplanted into NOD/SCID/IL2rγnull newborns via a facial vein. In all recipients injected with 105 hCD34+ or 2 × 104 hCD34+hCD38– CB cells, human hematopoietic cells were reconstituted at approximately 70% of chimerisms. A high percentage of the human hematopoietic cell chimerism persisted for more than 24 weeks after transplantation, and hCD34+ bone marrow grafts of primary recipients could reconstitute hematopoiesis in secondary NOD/SCID/IL2rγnull recipients, suggesting that this system can support self-renewal of human hematopoietic stem cells. hCD34+hCD38– CB cells differentiated into mature blood cells, including myelomonocytes, dendritic cells, erythrocytes, platelets, and lymphocytes. Differentiation into each lineage occurred via developmental intermediates such as common lymphoid progenitors and common myeloid progenitors, recapitulating the steady-state human hematopoiesis. B cells underwent normal class switching, and produced antigen-specific immunoglobulins (Igs). T cells displayed the human leukocyte antigen (HLA)–dependent cytotoxic function. Furthermore, human IgA-secreting B cells were found in the intestinal mucosa, suggesting reconstitution of human mucosal immunity. Thus, the NOD/SCID/IL2rγnull newborn system might be an important experimental model to study the human hemato-lymphoid system

Circulating CD34+ cells of primary myelofibrosis patients contribute to myeloid-dominant hematopoiesis and bone marrow fibrosis in immunodeficient mice.

INTRODUCTION: Primary myelofibrosis (PMF) is a clonal stem cell disorder characterized by myeloid dominant hematopoiesis and dysregulated proliferation of fibroblasts in the bone marrow. However, how these aberrant myeloid cells and fibroblasts are produced remains unclear. AIM AND METHODS: In this study, we examined in vivo engraftment kinetics of PMF patient-derived CD34+ cells in immunecompromised NOD/SCID/IL2rgKO (NSG) mice. Engrafted human cells were analyzed with flow cytometry, and proliferation of fibroblastic cells and bone marrow fibrosis were assessed with the histo-pathological examination. RESULTS: Transplantation of PMF patient-derived circulating CD34+ fractions into NSG newborns recapitulates clinical features of human PMF. Engraftment of human CD45+ leukocytes resulted in anemia and myeloid hyperplasia accompanied by bone marrow fibrosis by six months post-transplantation. Fibrotic bone marrow contained CD45-vimentin+ cells of both human and mouse origin, suggesting that circulating malignant CD34+ subsets contribute to myelofibrotic changes in PMF through direct and indirect mechanisms. CONCLUSION: A patient-derived xenotransplantation (PDX) model of PMF allows in vivo examination of disease onset and propagation originating from immature CD34+ cells and will support the investigation of pathogenesis and development of therapeutic modalities for the disorder

The development of adult T cell leukemia/lymphoma in renal transplant recipients: report of two cases with literature review

Abstract Backgrounds Therefore, reports on the risk of HTLV-1-related diseases in organ transplantation have increased in recent years, and the management of HTLV in renal transplantation remains a challenge. Patients and methods We retrospectively analyzed four HTLV-1-positive recipients or donors among 89 renal transplantation cases from 2006 to 2021. Results Among the four HTLV-1-positive recipients, two patients developed adult T cell leukemia/lymphoma (ATL) derived from recipients at approximately 3 years (1016 days and 1195 days) after renal transplantation. Case 1 developed lymphoma-type ATL (an extranodal primary cutaneous variant), including skin and pulmonary lesions. The patient achieved CR with FK tapering and CHOP therapy following cord blood stem cell transplantation. However, the patient died 101 days after ATL development because of a severe fungal infection. Case 2 developed acute-type ATL with an unusual phenotype of CD4+8+30+. The patient was treated with FK tapering and palliative therapy because of poor PS. Notably, in case 1, histopathological findings showed high numbers of PD-1-positive TIL cells in ATL, suggesting exhausted T cells and a correlation with the early onset of ATL. Furthermore, in Case 2, histopathological findings revealed CD 30 expression in ATL cells, suggesting the importance of CD 30 in ATL development. Importantly, case 2 showed typical driver mutations, including CCR4 truncation mutations of the C-terminal, TBL1XR1 mutation, and TP53 mutation in the splice site. Notably, our present study and our previous study on renal transplantation strongly indicated that two out of two and one out of 59 “recipient” positive cases developed ATL, respectively. Furthermore, our previous nationwide study 4 out of 10 “donor” positive cases developed HAM. These findings showed that ATL may be derived from HTLV-I+ recipient cells and HAM may be derived from HTLV-1+ donor cells, although the precise mechanism remains unknown. Conclusions Thus, early onset and rapid progression of ATL with poor outcomes should be considered in HTLV-1 endemic areas. Furthermore, immunological or genetic mechanisms may be related to the development of ATL after renal transplantation. We believe that the mechanism of onset of ATL after transplantation may be important when considering the immune environment of ATL itself