Immunodeficiencies: Congenital and Acquired

Abstract

Immunodeficiencies are classified as either primary diseases with a genetic origin or those that are secondary to an underlying disorder. X-linked (congenital) agammaglobulinemia results from a failure of pre-B cells to differentiate into mature B cells. The defect in Bruton’s disease is in rearrangement of immunoglobulin heavy chain genes. It occurs almost entirely in males and is apparent after 6 months of age following disappearance of the passively transferred maternal immunoglobulins. Patients have recurrent sinopulmonary infections caused by Haemophilus influenzae, Streptococcus pyogenes, Staphlococcus aureus, and Streptococcus pneumoniae. These patients have absent or decreased B cells and decreased serum levels of all immunoglobulin classes. The T-cell system and cell-mediated immunity appear normal.