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 on 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 γ/δ 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

Keywords: DiGeorge Syndrome - immunology, Adolescent, Aging - immunology, Autoantibodies - blood, Child, Child, Preschool, Cohort Studies, DiGeorge Syndrome - immunology, Immunoglobulin A - blood, Immunoglobulin G - blood, Infant, Newborn, Lymphocyte Activation, T-Lymphocytes - immunology