Dear Kruzn for a Kure Foundation,
First, we would like to kindly acknowledge the Foundation and all of those involved for supporting our research at Stanford University during 2020. Although this year has been challenging due to the COVID-19 pandemic, with your funding, we have advanced our project studying regulatory innate immune cells that may promote immune tolerance after abHaploHSCT (αβ T-cell/B-cell depleted haploidentical hematopoietic stem cell transplantation) in children with Schimke Immune Osseous Dysplasia (SIOD). Background: SIOD children urgently need HSCT to reconstitute the deficient immune system, as well as a kidney transplant to provide a healthy fully functional organ and a better quality of life. Three SIOD children were treated with abHaplo-HSCT and they subsequently received a kidney transplant from the same abHaplo-HSCT donor without longterm immunosuppressant treatment. This is a very innovative and efficacious strategy. Previous efforts to perform kidney transplant post-HSCT have been unable to completely eliminate the lifelong need of immunosuppressants, which negatively impact the quality of life of the patient. Importantly, this is the first time SIOD patients can go through an allogeneic HSCT without transplant-related complications. In fact, no patients died nor developed significative graft-versus-host disease or infections. Thus, we hypothesize that the presence of regulatory innate immune cells, such as gd T and Natural Killer (NK) regulatory subpopulations, especially in the first months post-abHaplo-HSCT in SIOD patients favors a tolerogenic environment that allows the solid organ to engraft and function. Understanding the underlying mechanisms of tolerance achieved in SIOD children will provide new clues to improve abHaplo-HSCT and to identify the best timing for solid organ transplants; a strategy that will translate to SIOD children and other pediatric patients currently waiting for an organ transplant.
Current research: In the immune monitoring data obtained from three SIOD children post-abHaplo-HSCT we observed high numbers of a NK cell subpopulation that may carry regulatory features. Within the first 90 days post-abHaplo-HSCT, the number of gd T cells is also abundant compared to other T cell populations and we believe that some of these cells can be regulatory. To date, the cell surface markers and the mechanisms of action of regulatory gd T and NK cells have not been fully elucidated. We attempted to identify gd T regs in three different healthy donors, however the gd T regs population was minimal to nonexistent, confirming the data available in literature. Thus, we successfully induced gd T cells in vitro to express regulatory protein markers using a cytokine cocktail. With the recent support of US$ 10.000,00 (ten thousand dollars) from Kruz for a Kure Foundation, we are currently developing functional assays to evaluate the ability of these cells to restrain T effector cell proliferation and to confidently characterize the regulatory potential of cytokine-induced gd T and NK subpopulations.
Perspective for 2021: Our goal is to proceed with single-cell experiments to characterize the phenotype of innate regulatory cells using CyTOF, a mass cytometry technique that assesses several cell surface and intracellular markers at the same time in a single-cell level. We will also use CITE-seq (single-cell RNA-seq combined with quantitative and qualitative information on cell surface proteins) to evaluate the molecular networks in gd T and NK regulatory cells. We anticipate to complete this task with an extra budget of US$ 65.000,00 (sixty-five thousand dollars). With a thorough investigation of these cells and regulatory networks, we will confidently analyze innate regulatory cells from the three SIOD patients in our cohort, and characterize their tolerogenic capacity. Once again, we thank Kruzn for a Kure Foundation for trusting in our research and for your incredible support to this project. With your continuous partnership, we will make several strides in finding the best strategies to cure SIOD and to translate our findings to other pediatric patients.
Priscila Ferreira Slepicka, Ph.D.
Dr. Alice Bertaina, MD, Ph.D. Postdoctoral Scholar Associate Professor in Pediatrics Inpatien