Summary The use of a spray system to coat meat rolls with egg solution resulted in the development of asthmatic type symptoms in eight of thirteen workers exposed to the spray. Symptoms were severe in five workers, less severe in two, and one worker experienced vague symptoms. Even though precipitins were present in nine of the workers there were no pyrexial episodes nor influenza‐like symptoms occurring some hours after inhaling the egg material to suggest extrinsic allergic alveolitis. All sera with precipitins reacted against an antigen in egg yolk, two sera only to this antigen but no precipitins to ovalbumin were detected. Lung function, X‐ray and haematology provided no evidence that the inhalation of egg had lasting detrimental effects. There was no correlation between clinical response, skin testing, IgE levels and precipitins, hence, for each individual none of these parameters is predictive. However, collectively the results show sensitization and this has been confirmed by lack of symptoms when a different method of coating the pastry was adopted.

Sixty staff working in a hospital operating theatre, where a case of humidifier fever had been identified, were studied together with 49 subjects working in other parts of the hospital. They each had a blood test for serology, a skin test, and a chest radiograph and completed a questionnaire. The theatre staff also had pulmonary function tests. The theatre humidifier was found to contain several organisms including amoebae and antigens cross-reacting highly with those implicated in previous outbreaks of humidifier fever. Of the 60 exposed subjects, 25 had developed antibodies, nine had probable symptoms of humidifier fever, and six possible symptoms. There was a strong association between symptoms and antibodies (p = 6 x 10-5 by Fisher Four subjects reacted to the challenge, including both those with antibodies and previous symptoms.

An Andersen sampler was used to collect different sized fractions of airborne dust within pigeon lofts. Antigens associated with pigeon breeders' lung were then measured using an ELISA technique. Levels of soluble antigen in the 0.5-5 microns range correlated significantly with airborne particle concentrations in the same range, determined by particle size analysis. However, antigenic material was not soley confined to the 0.5-5 microns fraction and was detected in particles up to 11 microns in diameter. Using both particle size analysis and ELISA in local pigeon lofts revealed significantly increased particles (up to x 50) and antigens (up to x 10) in some lofts employing litter materials to dehydrate voided pigeon droppings, compared with lofts cleaned regularly with no litter agent. Paradoxically, ventilation did not influence particle or antigen concentrations under static conditions or during loft cleaning. The settling rate of loft dusts correlated significantly with that of the litter used, suggesting litter particles were a carrier for soluble pigeon dropping components, but differences in particle numbers generated from the litters and litter/dropping combinations showed that an interaction between voided droppings and litter agents had occurred. A change from litter systems to regular cleaning was undertaken in two lofts, resulting in a marked decrease in respirable particles and antigens.

A method is described which assesses results obtained from an ELISA system for the determination of human serum levels of IgG class antibodies to Aspergillus fumigatus. The method is used to discriminate positive from negative samples, and significant antibody activity may be reported to the clinician, relative to a reference positive control serum monitored simultaneously under the same test conditions. Antibody content is expressed as the absorbance of a certain dilution of serum. Duplicate samples were analysed at a single serum dilution and their absorbtion values obtained from a semi-automated ELISA microplate reader. These were entered into a computer programmed to convert the data into units on a logarithmic scale. In parallel experiments, ELISA results were compared with those obtained by the techniques of counterimmunoelectrophoresis and double diffusion which measure precipitating antibody of all classes. A relatively good degree of correlation between tests was found only among sera with a high level of antibody.