[Significance of IgG serum levels in cystic fibrosis]

IgG serum levels were measured in 25 patients with cystic fibrosis aged 1 to 19 years and in 4 additional patients deceased over the last 4 years. Levels were correlated with a number of parameters. Twelve patients (group A) had raised IgG levels, and 17 (group B) normal or low levels. Age between groups did not differ. Patients in group A had lower Shwachman score (p less than 0.001), worse Chrispin and Norman radiologic score (p less than 0.05), lower weight (p less than 0.001) and height (p less than 0.05) and lower FVC (p less than 0.05), and FEV1 (p less than 0.01). Raised levels were associated with increased number of serum precipitins against Pseudomonas aeruginosa but not against Staphylococcus aureus. Raised IgG levels might be secondary to heavier bronchial infection, but there is growing evidence that immunologic response in cystic fibrosis may worsen the course of the disease.