Pulmonary consequences of congenital and acquired primary immunodeficiency states.

A sophisticated system of pulmonary host defense strives to maintain the functional integrity of the lung against the threats of infections, toxins, and malignancy. Congenital and acquired defects in the immune mechanisms of this host defense are associated with a variety of pulmonary disorders that include infections with usual or opportunistic organisms; inflammatory disorders; and malignancies. The age of the patient, associated abnormalities, family history, and the type of pulmonary and systemic diseases that are present provide clues to the specific underlying disorder. Laboratory tests including immunoglobulin levels, lymphocyte subset enumeration, and tests of lymphocyte function can help to confirm the clinical impression. Determination of the specific disorder allows the physician to anticipate possible complications, initiate appropriate prophylactic measures, and, in an increasing number of diseases, offer specific therapy.