Renewed immunity A thymus-tissue transplant enabled babies that were born with DiGeorge's syndrome
to develop functional immune systems (164: 69).
A congenital birth defect seen in humans, DiGeorge's syndrome
, involves the failure of the thymus to develop and an absence of circulating T-cells and cell-mediated immunity.
Clinicians estimate that DiGeorge's syndrome
affects 1 in 4,000 newborns and is the second most common cause of congenital heart defects.