Researchers from the National Institute of Allergy and Infectious Diseases (NIAID) have found that gene therapy can safely restore the immune systems of older children and young adults with X-linked severe combined immunodeficiency (SCID-X1), a rare inherited disorder that primarily occurs in male infants – during the three-month stage – due to the decreased amount of Immunoglobulin G (IgG) levels.
Gene “Interleukin 2 Receptor, Gamma,” abbreviated as IL2RG, provides instructions for making a protein known as the common gamma chain. This gamma chain, aka protein, is a component of several different receptors that are involved in immune system function. However, the mutations in the IL2RG genes prevent infection fighting immune cells from developing and functioning properly, thereby causing SCID-X1. This makes affected infants highly susceptible to life-threatening infections.
Once the infants are affected by SCID-X1, the most effective life-saving treatment is the transplantation of blood-forming stem cells, ideally from a genetically matched sibling donor. The ones without a matched sibling often receive stem cells from a parent, but it is not quite as effective as transplantation from a genetically matched sibling donor as it partially stores immunity. In most cases, such patients continue to experience complex medical problems, which in severe cases, may include chronic infections. Moreover, they also may require lifelong therapy.
In the study which is currently recruiting new participants, researchers investigated the safety and effectiveness of gene therapy combined with low-dose chemotherapy in five SCID-X1 patients with worsening immune systems. The patients involved in the study were between the ages of 7 and 24, and one or two of them have had received stem cells from a parent.
The researchers removed stem cells from the patients’ bone marrow and used a lentiviral vector to deliver a normal IL2RG gene to the cells. When the researchers infuse the corrected cells back into the patient, following a low dose of chemotherapy, to help the stem cells establish themselves and begin production of new blood cells, they saw substantial improvements in immunity and clinical status of the first two patients who received this therapy, with one patient continuing to improve after three years of therapy.
But, for the second patient who showed improvement, things did not go quite well. The patient died of pre-existing, infection-induced lung damage two years after receiving gene therapy. This clearly suggests that early treatment is crucial before organ damage becomes irreversible.
Well for the three other patients, who received the therapy three to six months ago, they are beginning to show improvements in their immune function. Researchers are ceaselessly monitoring the surviving patients. The results of the study will be published at the 57th ASH Annual Meeting & Exposition.
This is yet another proof that gene therapy is the most effective solution for almost every diseases. If gene therapy restores immunity in patients with X-linked severe combined immunodeficiency (SCID-X1), just imagine other possibilities too.
[Source(s) and Reference(s): NIAID, Lentiviral Gene Transfer for Treatment of Children Older Than Two Years of Age With X-Linked Severe Combined Immunodeficiency (XSCID), Image: Vimeo]