Immunoglobulin and antibody levels in bronchoalveolar lavage fluid from symptomatic and asymptomatic pigeon breeders.

Twenty-one symptomatic subjects with pigeon breeders' lung (PBL) and 10 asymptomatic pigeon breeders, with a similar exposure to pigeon antigens, underwent bronchoalveolar lavage. Total IgG, IgM and IgA in lavage fluid were determined as were specific antibody levels against antigens in pigeon serum and droppings. Results were converted to levels in epithelial lining fluid (ELF) using lavage and serum urea ratios. It was found that symptomatics represent a group that is hyperreactive to pigeon antigens compared with the asymptomatic group with significantly higher IgG, IgM, IgA levels as well as specific antibody levels against pigeon serum and droppings. Paired serum and ELF samples from 12 symptomatic subjects showed significantly elevated IgG, IgM and IgA levels in ELF compared with serum when values were expressed in terms of albumin. This strongly supports the concept of local production of immunoglobulins within the lung after inhaling immunogens as opposed to their diffusion from the vasculature. Results for IgA indicate that any putative protective role for this immunoglobulin is not valid in relation to the prevention of extrinsic allergic alveolitis. Analysis of smoking habits, lung immunoglobulins and response to inhalation challenge confirm the negative influence of smoking on total and functional lung immunoglobulins; however, levels in the ELF of ex-smokers suggest that the effect of smoking is not permanent. Smoking did not prevent responses to inhalation challenge.