TRIM5

Chronic Granulomatous Disease (CGD) is a rare inherited disorder in which patients suffer from severe infection and inflammation. The first indications of disease usually appear in early childhood. The basic defect has been found to be lie in specialised white blood cells called phagocytic cells, which are responsible for engulfing and destroying germs. In CGD, there is a defect in an enzyme (known as the NADPH-oxidase) that is responsible for generating bleach like substances that are important for killing some important germs. In one form of the disease known as p47 AR-CGD (which accounts for 30% of patients), there are defined mistakes in a gene called NCF1. This gene is needed to form a key component of NADPH-oxidase.
In many cases, patients can be protected from infection by constant intake of antibiotics. However, in others potentially life-threatening infections break through. In some cases patients also develop serious inflammation requiring high doses of drugs such as steroids. CGD can be cured by bone marrow transplant and the best results are available when a matched sibling donor is available. Transplant from unmatched donors have a much worse outcome and as a result alternative treatments for patients without a matched donor are highly desirable.
Gene therapy of p47 AR-CGD is performed by introducing a normal copy of the human NCF-1 gene into the blood forming stem cells in the patients' bone marrow by using a gene carrier (in this study called a lentiviral vector). After treatment of the bone marrow cells in a specialised laboratory they are given back to the patient and will grow into functional phagocytic cells. There have been no previous clinical trials for patients with p47 AR-CGD however there have been previous gene therapy clinical trials conducted in the UK for patients with the most common form of CGD, known as X-CGD.

Severe combined immunodeficiency disorder (SCID) is a heterogeneous group of inherited disorders characterized by a profound reduction or absence of T lymphocyte function, resulting in lack of both cellular and humoral immunity. SCID arises from a variety of molecular defects which affect lymphocyte development and function. The most common form of SCID is an X-linked form (SCID-X1), which accounts for 30-50% of all cases. SCID-X1 is caused by defects in the common cytokine receptor gamma chain, which was originally identified as a component of the high affinity interleukin-2 receptor (IL2RG).
Allogeneic haematopoietic stem cell transplantation (HSCT), which replaces the patient's bone marrow with that of a healthy donor, is the only treatment that definitively restores the normal function of the bone marrow. HSCT is the first choice of treatment for patients with signs of bone marrow failure and a fully-matched related donor. However, patients without a fully-matched related donor have much worse overall outcomes from HSCT.
This study will investigate whether patients with SCID-X1 without a fully matched related donor may benefit from gene therapy. To do this the investigators propose to perform a phase I/II clinical trial to evaluate the safety and efficacy (effect) of gene therapy for SCID-X1 patients using a lentivirus delivery system containing the IL2RG gene. Up to 5 eligible SCID-X1 patients will undergo mobilisation and harvest of their haematopoietic stem precursor cells (HPSCs). In the laboratory the disabled lentivirus will be used to insert a normal human IL2RG gene into the patient's harvested HPSCs. Patients will receive chemotherapy conditioning prior to cell infusion, in order to enhance grafting. The genetically corrected stem cells will then be re-infused into the patient. Patients will be followed up for 2 years. This trial will determine whether gene therapy for SCID-X1 using a lentiviral vector is safe, feasible and effective