Intrinsic abnormalities of lymphocyte counts in children with down syndrome.

Objective: Down syndrome (DS) is associated with an increased frequency of infections, hematologic malignancies, and autoimmune diseases, suggesting that immunodeficiency is an integral part of DS that contributes significantly to the observed increased morbidity and mortality. We determined the absolute counts of the main lymphocyte populations in a large group of DS children to gain further insight into this immunodeficiency.

Study Design: In a large group of children with DS (n = 96), the absolute numbers of the main lymphocyte subpopulations were determined with 3-color immunophenotyping using the lysed whole-blood method.