[IGA concentration in serum, sputum and bronchoalveolar lavage in chronic bronchitis]

IgA concentrations in serum, sputum and bronchoalveolar lavage were determined in 11 patients with chronic obstructive lung disease exacerbated by infection and in 22 with similar disease during an infection-free period. Patients with infection had a higher serum-IgA concentration than those without. But there was no difference in sputum-IgA concentration between the two groups. Both for sputum and broncho-alveolar lavage there was a positive correlation between anti-elastolytic inhibition capacity and IgA concentration. In vitro it has been demonstrated that IgA concentration measured immunologically decreases with increasing elastase concentration, in line with increasing free elastolytic activity. Local IgA deficiency in patients with infection apparently results from proteolytic splitting of the immunoglobulin.