Aspects of serum and sputum antibody in chronic airways obstruction.

Immunoglobulin levels and precipitating antibody against a range of microbial antigens were 
measured in simultaneously collected serum and sputum samples from patients with 
chronic bronchitis (11), cystic fibrosis (9), bronchiectasis (9), and asthma (4). 
Sputum was prepared by dialysis and high-speed centrifugation methods. Results showed 
that it was possible to detect precipitating antibody in the sputum, 
and the rate was increased when both methods were used. A 
discrepancy was noted between the detection rate in the sputum and 
serum. This, combined with the lack of correlation between sputum and 
serum immunoglobulins, lack of relationship between bronchial inflammation and sputum immunoglobulins, 
and the lack of IgM in the sputum suggested that the 
antibody and immunoglobulin were locally produced. Sputum IgA (7S) in patients 
with chronic bronchitis was significantly lower (P less than 0-05) than 
that found in patients with cystic fibrosis and bronchiectasis. Significant differences 
(P less than 0- 05) were also noted in serum IgG 
levels between patients with chronic bronchitis, bronchiectasis, and cystic fibrosis while 
serum IgM levels in patients with chronic bronchitis were significantly lower 
(P less than 0-05) when compared to serum levels in patients 
with cystic fibrosis. The presence of precipitating antibody in the sputum 
raises the possibility that type III reactions may be important in 
the pathogenesis of these conditions. 