Airway secretory IgA concentrations in patients with lung cancer. Evaluation of the uninvolved lung

To determine whether concentrations of the primary airway immunoglobulins (SIgA, IgG) are altered in the uninvolved lung of patients with lung cancer, we determined concentrations of SIgA and IgG in bronchial washings recovered from a proximal airway of the uninvolved lung in 24 patients with lung cancer and in ten patients with benign lung disease. When standardized for the amount of total protein recovered (SIgA/TP, IgG/TP), bronchial washings recovered from the uninvolved lung of lung cancer patients demonstrated a significantly decreased SIgA/TP ratio compared to control subjects (.14 +/- .02 vs .31 +/- .05, SEM, p less than 0.05). There were no differences in the IgG/TP ratios. Lung cancer patients with a decreased serum albumin (less than 3.2 g/dl) had a significantly decreased SIgA/TP ratio in bronchial washings compared to patients with a higher serum albumin (.08 +/- .03 vs .18 +/- .04, SEM, p less than 0.05). The decreased relative concentration of airway SIgA in lung cancer patients may adversely affect airway defenses against bacterial colonization.