Bacterial precipitins and their immunoglobulin class in atopic asthma, non-atopic asthma, and chronic bronchitis

In a study of groups of patients with atopic (extrinsic) asthma, non-atopic (intrinsic) asthma, and chronic bronchitis, no difference could be detected in the numbers having precipitating antibodies against species specific antigens from Staphylococcus aureus or Streptococcus pneumoniae compared to suitably matched control subjects. Precipitating antibodies against species specific antigens from Haemophilus influenzae, demonstrated in this investigation by double diffusion in agar gel, were found much more frequently in patients with chronic mucopurulent or obstructive bronchitis (50%) than in either asthmatic subjects (6%) or normal controls (6%) (P = less than 0.0005). While the precipitating antibody demonstrated in these patients against the extracts of Str. pneumoniae and Staph. aureus was in the IgG class alone, IgM and IgA antibody were detected against the species specific but not the non-species specific antigens of H. influenzae. These results underline the importance of H. influenzae as an infecting agent in chronic bronchitis and suggest that the finding of precipitins against the species specific H1 and H2 antigens of this bacterium denotes infection either concurrently or in the recent past. There is no evidence to suggest from this study that infection with Staph. aureus, Str. pneumoniae or H. influenzae is any more common in asthmatics as a group compared to controls or between patients with the non-atopic (intrinsic) and atopic (extrinsic) form of the disease.