Serum antistaphylococcal alpha-haemolysin titres in cystic fibrosis.

Abstract
The staphylococcal anti-a-hemolysin (AAH) titers of 138 patients with cystic fibrosis (CF) indicate there is an immunological response to their persistent bacterial flora. The C F patients over 6 months of age had median serum titers of AAH above those of control children. The 21 infants under 6 months of age all showed titers less than 1 unit/ml. Very low levels of AAH were found in the bronchial secretions tested even when the concomitant serum titers were high. The fluctuations of serial serum AAH in many CF patients paralleled the changing clinical state; in others there was no correlation.