SPECIFIC IGG2 ANTIBODIES TO PSEUDOMONAS-AERUGINOSA LIPID-A AND LIPOPOLYSACCHARIDE ARE EARLY MARKERS OF CHRONIC INFECTION IN PATIENTS WITH CYSTIC-FIBROSIS

The IgG subclass antibody response to the two parts of Pseudomonas aer uginosa lipopolysaccharide; endotoxic lipid A and the O-polysaccharide , were investigated in a retrospective longitudinal study involving 16 patients with cystic fibrosis and chronic P. aeruginosa lung infectio n. The purpose of the study was to see if any of the IgG subclasses of either specificity could be used as prognostic markers in the develop ment and subsequent course of the lung disease. IgG2 anti-lipid A, IgG 3 anti-lipid A, and IgG2 anti-polysaccharide showed a significant posi tive correlation with deteriorating pulmonary function already before chronic P. aeruginosa lung infection was diagnosed as well as in subse quent years. The findings suggest antigenic exposure of the patient be fore chronic infection is detected by routine sputum examinations, and further support our previous findings of a critical role of the IgG s ubclass response in modulating the course of inflammatory lung damage in these patients.