Hematopoietic Stem Cell Transplants for Severe Combined Immune Deficiency and Systemic Sclerosis

Funding Type: 
Disease Team Research I
Grant Number: 
DR1-01471
ICOC Funds Committed: 
$0
Disease Focus: 
Amyotrophic Lateral Sclerosis
Neurological Disorders
Stem Cell Use: 
Embryonic Stem Cell
Cell Line Generation: 
Embryonic Stem Cell
Public Abstract: 
Blood stem cells, which reside in the bone marrow (BM) can generate every type of blood and immune cell. They are the only cells necessary to re-establish blood formation if the BM is wiped out by disease or by treatments such as radiation or chemotherapy, as is the case for people who undergo a BM transplant. BM transplants have been performed for >50 years as life-saving procedures for many illnesses. However, patients do not receive pure blood stem cells, and the procedure is considered high risk mainly because BM cells received from a donor contain a combination of blood stem cells plus other mature immune cells. These mature cells pose a conundrum to physicians because on the one hand, the donor’s mature cells can be beneficial to the patient by assisting blood stem cells to take root and grow in the recipient as well as potentially helping battle tumors in cancer patients. However on the other hand, these mature donor cells can attack the recipient’s tissues, perceiving them as foreign and causing a syndrome called graft-versus-host disease (GVHD). Unfortunately, 10-20% of patients that undergo a transplant die from the consequences of GVHD. In the last decade technologies were developed to purify blood stem cells eliminating mature immune cells, thereby eliminating the danger of GVHD. However, transplant physicians remained hesitant to use such grafts because of concerns that purified stem cells without the accompanying immune cells would not take and grow in the recipient. Members of this team have therefore worked out new ways in mice that may be used on patients so that they will accept purified blood stem cell grafts without significant side effects. The reagents we will develop belong to a class of proteins called antibodies. The specialized antibodies we will use are biologic tools that allow us to both purify human stem cells, and eliminate blood stem cells in the recipient thereby clearing the BM for donor cells. We plan to adapt the technologies that have worked successfully in mice to treat two different disorders for whom BM transplant can be curative, but if performed by conventional methods is very high risk and can be fatal for the patient. The disorders we aim to cure by this approach are the childhood disease called severe combined immune deficiency (SCID), and the other is an autoimmune disease called systemic sclerosis (SSc). Children born with SCID lack immune cells to fight infections and without treatment die within the first year of life. Patients with severe forms of SSc experience thickening and tightening of the skin, lung and gastrointestinal problems which ultimately results in death after several years of suffering. We intend for these studies to result in superior treatments for these diseases. Since blood stem cell transplants have the capability of curing many other childhood and autoimmune disease, the ultimate impact of our studies will potentially be on a much broader spectrum of diseases.
Statement of Benefit to California: 
In 2004 California citizens passed a historic proposition supporting research that could result in the use of stem cells to cure many diseases. As a result, public and private institutions in California have emerged as leaders in this field, and scientists are now well on the path to producing tissues from primitive embryonic stem cells (ESCs). As scientists learn to direct these cells to become the tissues needed to replace damaged or failing ones, the obstacle of a patient rejecting these new tissues is a problem that must be overcome. The studies proposed by this Team address this issue. Tissues or organs are rejected because they come from donors who are genetically different. Similarly, tissues derived from ESCs will be genetically different from patients who need these tissues and therefore at risk for rejection. In order to prevent tissue rejection, patients that undergo transplants of organs (i.e, heart, kidney, lung) must remain life-long on medications to suppress their white blood cells from rejecting the grafts. There is one group of transplant patients that are routinely taken off their immune suppressive drugs -- bone marrow transplant (BMT) patients. These patients undergo BMT to cure them of severe cancers or inherited blood diseases. However, they can be liberated from their immune suppressive drugs because donor blood forming stem cells that take root in their bodies make the white blood cells that decide which tissues are identified as “foreign” or “self”. New white blood cells re-educate the recipient’s immune system to accept donor tissues as self. Thus, a state of harmony called immune tolerance is achieved so that donor blood is made without difficulty, and, in theory, the recipient can accept transplanted organs from the marrow donor without need for immune suppression. A similar strategy can be adapted to induce immune tolerance to tissues derived from ESCs. Remarkably, BMT also has the capability to cure autoimmune diseases such as multiple sclerosis, juvenile diabetes and many others. The major obstacle to use BMT beyond the treatment cancers has been the dangers associated with the procedure. This Team will take a crucial step to make BMT safer by transplanting only purified blood stem cells. The benefits of these potential advancements to our state are many. First and foremost is the health and well-being of all Californians who face the many diseases treatable by BMT. In addition, it is a simple fact that with every major scientific advancement come immediate economic benefits to the region that generated those advancements. These benefits can manifest in the form of academic donations from sources around the world, service industries that support the medical establishments that practice the procedures, and hi tech companies who receive their funding globally. This activity can all result in greater investment in California and continued job creation that has made California such a desirable place to live.
Progress Report: 
  • Considerable progress was made on transitioning cells and cell production methods from research-scale to translational/clinical scale. Specifically, Year 1 activities were focused on transitioning from research to pilot-scale cell production methods, and characterization of the animal amyotrophic lateral sclerosis (ALS) disease model. These activities were essential because cellular therapy development is a multi-stage process with increasing stringency over time in terms of the increased focus on the details of the methods, stringent requirements for reagents/materials, greater scale, and more thorough product characterization during the transition from early research to an approved cellular therapy.
  • During Year 1, small-scale embryonic stem cell (ESC) growth and differentiation methods previously developed for research at Life Technologies were further developed at a larger pilot-scale, which provided enough cells to perform early animal pre-clinical studies and cell characterization. In addition to the increased scale of cell production, where possible, research grade reagents and materials were substituted with reagents and materials that would be required or preferred for producing a cell therapy for use in humans [produced under Good Manufacturing Practices (GMP), non-animal origin, well characterized]. These conditions are not ideal for many ESC lines, and only 1 of the 4 starting ESC lines was able to adapt successfully to these culture conditions. To increase the number of potential clinical ESC candidate cell lines, we acquired 2 additional ESC lines, UCFB6 and UCSFB7 from the University of California, San Francisco. Development is ongoing to ensure the cell processing methods are robust and scalable for the increased cell numbers required for the large-scale animal studies in Year 2. Cells from the pilot-scale production are being subjected to deep sequencing as part of the development of molecular characterization methods that may provide future quality control assays.
  • During Year 1, further studies of a rat ALS disease model were performed to: 1) optimize cell injection methods; 2) improve characterization of disease onset and progression in the rat model; 3) evaluate the utility of behavioral and electrophysiology tests for following the disease; and 4) evaluate histology methods for measuring neuron damage and detection of implanted cells, which will be used to optimize the large-scale efficacy studies planned for Year 2. We discovered that several time-consuming analysis approaches for efficacy evaluation could be replaced by simpler, more cost effective approaches. Additionally, the Year 1 studies tested and ensured that the team could handle an aggressive cell implant schedule, twice daily immunosuppression, demanding behavioral and electrophysiology assessments, and extensive histology evaluations.
  • Considerable progress was made on transitioning cells and cell production methods from research-scale to translational/clinical scale, including initial cell production in a GMP facility with GMP compatible production methods. Additionally, extensive characterization of the amyotrophic lateral sclerosis (ALS) disease animal model was completed and cells were evaluated for potential efficacy in this ALS disease animal model. These activities are key for continued progress in cellular therapy development, which is a multi-stage process that requires increasing focus on the details of the methods, stringent requirements for reagents/materials, greater scale, and more thorough product characterization during the transition to an approved cellular therapy.
  • Specifically, we made significant progress in three major areas:
  • First, we found evidence for efficacy using neural stem cells made at Life Technologies. In brief, during Year 1, the rat ALS disease model was shown to be a more aggressive disease model with an earlier disease onset and more rapid progression to end-stage and death than the model that had been used in previous studies. During Year 2, this more aggressive ALS disease model was further characterized with the identification of a reliable marker of disease onset, and demonstration that alpha motor neuron sparing by implanted cells could be detected and measured even, despite the aggressive nature of disease progression in this rat model.
  • We found that H9 NSCs produced by Life Technologies, when implanted into the rat ALS disease model, survived, migrated extensively into the area where alpha motor neurons are located, differentiated into cells that appear to be astrocytes, and provided a protective effect for the alpha motor neurons. This protective effect was determined by comparing the survival of alpha motor neurons on the side of the rat spinal cord where NSCs were implanted with the side of the spinal cord that did not have cells implanted. The side of the spinal cord where the NSCs were implanted showed approximately 10% more surviving alpha motor neurons than the matching side of the spinal cord that did not have cells implanted.
  • Second, cells from the various production methods were subjected to gene sequencing as part of the development of molecular characterization methods. This sequencing information was critical to identify whether cells produced by various methods were typical for the cell type, or exhibited qualities that indicated they were not optimal cell populations. These methods will be used to identify optimal markers for characterizing cell populations as part of current cell production development and for future quality control assays.
  • Third, during Year 2, Life Technologies further developed their pilot-scale embryonic stem cell (ESC) growth and differentiation methods to be more easily adaptable to cell production under Good Manufacturing Practices (GMP). This involved increasing the scale of cell production, and where possible, substituting reagent grade reagents and materials with reagents and materials that would be required or preferred for producing a cell therapy for use in humans (produced GMP, non-animal origin, well characterized). These conditions are not ideal for many ESC lines, and in Year 1, only one (H9) of the 4 starting ESC lines was successfully adapted to these culture conditions, however, 3 additional ESC lines were acquired to increase the number of potential clinical ESC candidate cell lines. One of these ESC lines (UCSFB7 from the University of California, San Francisco) was successfully adapted to the pilot ESC culture conditions, and resulted in the production of NSCs, and with AP production in progress. Because the research version of ESC line H9 has been used to successfully produce NSCs at Life Technologies, agreements are in progress for City of Hope for NSC cell production using the H9 ESCs, that have been banked under GMP conditions at City of Hope. In addition, pilot-scale cell production was initiated earlier than originally planned at the University of California, Davis GMP facility. The plan is to produce NSCs and APs under conditions that UC Davis has found to be successful in the past, and transition these methods to GMP compliance. To date, UC Davis has produced ESCs from 3 ESC lines [UCSF4, UCSF4.2 (a.k.a. UCSFB6) and UCSF4.3 (a.k.a. UCSFB7] and has produced NSCs from ESC line UCSF4. The UCSF4 NSCs are scheduled to be shipped to UCSD for testing in the ALS disease animal model in early June, 2012, and NSC production from ESC lines UCSF4.2 and UCSF4.3 is expected to begin in late June 2012.

© 2013 California Institute for Regenerative Medicine