Increased risk of respiratory tract infections in children with Down syndrome: the consequence of an altered immune system.

Down syndrome (DS) is the most common chromosomal abnormality among live-born infants. Respiratory tract infections are the most important cause of mortality in individuals with DS at all ages. In recent decades several studies have been performed to elucidate abnormalities of the immune system in DS. However, the influence of the immune system on the occurrence of respiratory tract infections in these children has never been reviewed.