Serum precipitins against respiratory tract pathogens in 522 "normal" children, and 48 cases of cystic fibrosis treated with cloxacillin.

Well children show a steady increase of staphylococcal precipitins throughout life. Lower 
incidences are found for precipitins against H. influenzae, Pneumococcus, and haemolytic 
streptococcus. Precipitins against Proteus, Pseudomonas, and Klibsiella are rare. There are 
marked differences between the normal children and the cloxacillin-treated children with 
cystic fibrosis in respect to Pseudomonas and H. influenzae which rise 
to over 50% of cystic fibrosis children in the third quinquennium. 
However, the development of staphylococcal precipitins can be prevented by continuous 
antistaphylococcal therapy. 