The two 3-year-olds were very, very sick. One was bleeding internally, suffered from severe eczema and anemia, and had multiple infections in his lungs and colon. The other had a dangerously low platelet count, recurring respiratory tract infections, and a life-threatening salmonella infection in his blood. Both turned up in pediatric hematologist Christoph Klein’s office in 2006, their parents clutching tightly to the hope that Klein might be able to save their children’s lives.
Video: A stem cell therapy success story
Klein, then at the Hannover Medical School in Germany, was running the first-ever gene therapy trial for Wiskott-Aldrich Syndrome, a rare and life-threatening disease caused by mutations in WAS, a gene whose protein product normally regulates the formation of actin polymers in hematopoietic cells. A dearth of functional WAS protein causes blood and immune system disorders, susceptibility to infections, and ...
