Abstract
Background: DiGeorge syndrome is a relatively common congenital disorder with developmental defects, including hypoplasia or pathologic migration of the thymus, associated with deletion of contiguous genes oil chromosome 22. We prospectively followed a cohort of children with confirmed 22q11.2 deletion.
Material/Methods: One to six repeated examination were performed in 13 boys and 21 girls, age 4 days to 19 years. Due to the proposed role of the thymus in T lymphocyte selection, we studied T lymphocytes and their function, and also the presence of double positive CD4+CD8+ and gamma/delta T lymphocytes in peripheral blood.
Results: A low number of T lymphocytes was detected in the majority of patients before the age of 2 years. Both spontaneous and PHA-induced proliferation were unexpectedly higher than in normal samples from children < 2 years old.
Both T cell numbers and function normalized thereafter in the majority of patients. Double positive T cells were detected in one boy, together with transient positivity of antinuclear antibodies. gamma/delta T cells were greater than 5% in 21% of the children.
In our 5-year prospective study we have not yet observed serious clinical signs of immunodeficiency or autoimmunity in these patients, except for repeated respiratory infections. Conclusions: All patients classified as partial diGeorge syndrome presented with delayed but gradual development of immune function against a background of impaired support by the thymus.