The long-term effect of a positive pressure respirator on the specific antibody response in pigeon breeders.

A group of pigeon fanciers with Pigeon Breeder's Lung wore a positive pressure respirator with a full mask and hood when working with pigeons. Serial measurements of specific IgG antibody to pigeon globulin (ELISA) were made in 22 subjects. Thirteen wore a respirator (monitored over 14 months) and nine did not (monitored over 3 months). Following introduction of the respirator, the serum antibody to pigeon globulin significantly decreased when compared with the non-respirator group. This fall in antibody persisted over 14 months reflecting the reduction of antigen inhalation. Although circulating antibody decreased in all those wearing respirators, the remaining levels were still within the range that can be associated with clinical symptoms possibly because of inward leakage of antigen bypassing the filter.