DETECTION OF SPECIFIC ANTIBODIES IN IMMUNE-COMPLEXES OF FARMERS LUNG PATIENTS

The authors examined 23 precipitin-positive symptomatic patients with Farmer's Lung (FL) and compared them to different groups of exposed as ymptomatic precipitin-positive (EAPP) and precipitin-negative (EAPN) f armers. The sera were tested using several techniques (i.e., immunodif fusion and ELISA for specific antibodies; polyethylene glycol [PEG] fo r circulating immune complexes [CIC]) in an attempt to find an in vitr o test correlated with the disease which could also provide an insight into the pathogenetic mechanisms of Farmer's Lung. Circulating immune complexes formed by IgG were significantly higher in Farmer's Lung pa tients than in EAPP subjects. In polyethylene glycol precipitates from Farmer's Lung patients, specific antibodies found by ELISA correlated well with serum positivity, but they were not found in EAPP subjects. The possibility that the circulating immune complexes found were Ig a ggregates was ruled out, as was the possibility that the antibodies fo und in the polyethylene glycol precipitate were due to an unspecific l ink. The authors suggest that the circulating immune complexes of Farm er's Lung patients contain specific antibodies and that since their co mposition is different in EAPP subjects, these circulating immune comp lexes may play a role in the pathogenesis of the disease.