Overview

Severe Combined Immunodeficiency (SCID), also known as “Bubble Boy Disease,” is a rare, fatal genetic disease that causes babies to be born without functioning immune systems. SCID can be caused by a number of mutations in genes required for the formation of lymphocytes: the immune cells in our body responsible for fighting off a variety of infections.

Sometimes, bad copies of these genes are inherited from the parents; other times, they arise spontaneously. Because babies born with SCID do not produce functional lymphocytes, their ability to fight off infections or diseases is severely limited; even minor viral illnesses can be deadly. Before there were treatments, SCID babies generally died within their first year of life.

Bubble Boy Disease is a rare, fatal genetic disease that causes babies to be born without functioning immune systems.

Currently, the standard treatment for SCID is a bone marrow transplant, a procedure in which blood-forming stem cells from a healthy donor are transplanted to provide a source for normal lymphocytes to replace the recipient’s dysfunctional lymphocytes. Unfortunately, because bone marrow transplants often involve powerful, toxic agents, they carry risks for SCID babies, whose immune systems are already significantly compromised.

Progress Towards A Cure

A team led by Dr. Donald Kohn, at the University of California, Los Angeles (UCLA), has developed a cure for this life-threatening disease, by collecting some of the baby’s own blood-forming stem cells, and modifying them by adding a normal copy of the missing gene. These corrected blood-forming stem cells can make normal immune cells, which give babies protective immune systems. In a clinical trial at UCLA, Kohn and his team cured 30 of 30 babies with SCID.

In a clinical trial at UCLA, Dr. Kohn and his team cured 30 of 30 babies with SCID.

Another team, led by Dr. Judith Shizuru at Stanford University, as well as Dr. Mort Cowan and Dr. Jennifer Puck at the University of California, San Francisco (UCSF) is pursuing an approach that would allow safer, “chemotherapy-free” bone marrow transplants. The key is an antibody that recognizes and targets the defective blood-forming stem cells in SCID patients, and specifically eliminates them, without killing other healthy cells.

This therapy is currently being tested in a human clinical at Stanford University. If successful, the applications of this work could extend to many other blood disorders and autoimmune diseases, as well as organ transplants.