Curative potential of allogeneic hematopoietic stem cell transplant in type 1 diabetes

Correction of T-Cell Repertoire and Autoimmune Diabetes in NOD Mice by Non-myeloablative T-Cell Depleted Allogeneic HSCT

The induction of partial tolerance toward pancreatic autoantigens in the treatment of type 1 diabetes mellitus (T1DM) can be attained by autologous hematopoietic stem cell transplantation (HSCT). However, most patients treated by autologous HSCT eventually relapse. Furthermore, allogeneic HSCT which could potentially provide a durable non-autoimmune T-cell receptor (TCR) repertoire is associated with a substantial risk for transplant-related mortality. We have previously demonstrated an effective approach for attaining engraftment without graft versus host disease (GVHD) of allogeneic T-cell depleted HSCT, following non-myeloablative conditioning, using donor-derived anti-3rd party central memory CD8 veto T cells (Tcm). In the present study, we investigated the ability of this relatively safe transplant modality to eliminate autoimmune T-cell clones in the NOD mouse model which spontaneously develop T1DM. Our results demonstrate that using this approach, marked durable chimerism is attained, without any transplant-related mortality, and with a very high rate of diabetes prevention. TCR sequencing of transplanted mice showed profound changes in the T-cell repertoire and decrease in the prevalence of specific autoimmune T-cell clones directed against pancreatic antigens. This approach could be considered as strategy to treat people destined to develop T1DM but with residual beta cell function, or as a platform for prevention of beta cell destruction after transplantation of allogenic beta cells.

Treatment of insulin-dependent diabetes by hematopoietic stem cell transplantation

Type 1 diabetes (T1D) is an autoimmune disease resulting from the demolition of β-cells that are responsible for producing insulin in the pancreas. Treatment with insulin (lifelong applying) and islet transplantation (in rare cases and severe diseases), are standards of care for T1D. Pancreas or islet transplantation have some limitations, such as lack of sufficient donors and longtime immune suppression for preventing allograft rejection. Recent studies demonstrate that autologous hematopoietic stem cells (HSC) can regenerate immune tolerance against auto-antigens. Taking advantage of this feature, autologous HSC transplantation (auto-HSCT) is likely the only treatment for T1D that is associated with lasting and complete remission. None of the other evaluated immunotherapies worldwide had the clinical efficacy of auto-HSCT. Therapy with auto-HSCT is insulin-independent rather than reducing insulin needs or delaying loss of insulin production. This review provided the latest findings in auto-HSCT for treatment of T1D.

Hematopoietic stem cell transplantation recovers insulin deficiency in type 1 diabetes mellitus associated with IPEX syndrome

Immune dysregulation, polyendocrinopathy, enteropathy, and X-linked (IPEX) syndrome is an autoimmune disorder caused by the dysfunction of FOXP3, which leads to regulatory T-(Treg) cell dysfunction and subsequently autoimmunity including type 1 diabetes mellitus (T1D). Presently, allogeneic hematopoietic stem cell transplantation (HSCT) is a potential curative therapy for IPEX syndrome, but not for T1D. Generally, after complete loss of pancreatic β-cells, HSCT cannot improve the prognosis of T1D. Here, we report the case of a 16-year-old adolescent with late-onset of FOXP3 R347H mutation associated IPEX syndrome with T1D, where insulin dependency was ameliorated following HSCT. This patient with insulin-dependent diabetes mellitus required insulin dosage of 1.28 U/kg/day for 1 month before HSCT. Although the results of glucose homeostasis before HSCT revealed impaired insulin secretion and low ΔC-peptide immunoreactivity (CPR, 1.0 ng/mL), the patient withdrew insulin infusion and remained euglycemic at 15 months after HSCT, and had normal β-cell function with improved ΔCPR (3.4 ng/mL) at 20 months after HSCT. The present case suggests that HSCT for T1D-associated IPEX syndrome improves Treg deficiency and prevents elimination of β-cells. We speculate that the period from the onset of T1D to HSCT could affect the therapeutic efficacy for T1D with IPEX, and early intervention with HSCT before or immediately after the onset of DM can rescue β-cells and remit T1D completely. Our study elaborates not only the therapeutic strategy for T1D with IPEX, but also the pathogenic mechanism in general T1D.

Transplantation of MHC-mismatched mouse embryonic stem cell-derived thymic epithelial progenitors and MHC-matched bone marrow prevents autoimmune diabetes

Background

Type 1 diabetes (T1D) is an autoimmune disease resulting from the destruction of insulin-secreting islet β cells by autoreactive T cells. Non-obese diabetic (NOD) mice are the widely used animal model for human T1D. Autoimmunity in NOD mice is associated with particular major histocompatibility complex (MHC) loci and impaired islet autoantigen expression and/or presentation in the thymus, which results in defects in both central and peripheral tolerance. It has been reported that induction of mixed chimerism with MHC-mismatched, but not MHC-matched donor bone marrow (BM) transplants prevents the development T1D in NOD mice. We have reported that mouse embryonic stem cells (mESCs) can be selectively induced in vitro to generate thymic epithelial progenitors (TEPs) that further develop into thymic epithelial cells (TECs) in vivo to support T cell development.

Methods

To determine whether transplantation of MHC-mismatched mESC-TEPs could prevent the development of insulitis and T1D, NOD mice were conditioned and injected with MHC-mismatched B6 mESC-TEPs and MHC-matched BM from H-2^g7 B6 mice. The mice were monitored for T1D development. The pancreas, spleen, BM, and thymus were then harvested from the mice for evaluation of T1D, insulitis, chimerism levels, and T cells.

Results

Transplantation of MHC-mismatched mESC-TEPs and MHC-matched donor BM prevented insulitis and T1D development in NOD mice. This was associated with higher expression of proinsulin 2, a key islet autoantigen in the mESC-TECs, and an increased number of regulatory T cells.

Conclusions

Our results suggest that embryonic stem cell-derived TEPs may offer a new approach to control T1D.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1347-1) contains supplementary material, which is available to authorized users.