Quantifying serum antibody in bird fanciers' hypersensitivity pneumonitis.
BACKGROUND
Detecting serum antibody against inhaled antigens is an important diagnostic adjunct for hypersensitivity pneumonitis (HP). We sought to validate a quantitative fluorimetric assay testing serum from bird fanciers.


METHODS
Antibody activity was assessed in bird fanciers and control subjects using various avian antigens and serological methods, and the titer was compared with symptoms of HP.


RESULTS
IgG antibody against pigeon serum antigens, quantified by fluorimetry, provided a good discriminator of disease. Levels below 10 mg/L were insignificant, and increasing titers were associated with disease. The assay was unaffected by total IgG, autoantibodies and antibody to dietary hen's egg antigens. Antigens from pigeon serum seem sufficient to recognize immune sensitivity to most common pet avian species. Decreasing antibody titers confirmed antigen avoidance.


CONCLUSIONS
Increasing antibody titer reflected the likelihood of HP, and decreasing titers confirmed antigen avoidance. Quantifying antibody was rapid and the increased sensitivity will improve the rate of false-negative reporting and obviate the need for invasive diagnostic procedures. Automated fluorimetry provides a method for the international standardization of HP serology thereby improving quality control and improving its suitability as a diagnostic adjunct.
McSharry
Charles
C
Division of Immunology, Infection and Inflammation, University of Glasgow, Western Infirmary, Glasgow G11 6NT, UK. cms4q@clinmed.gla.ac.uk
Dye
George M
GM
Ismail
Tengku
T
Anderson
Kenneth
K
Spiers
Elizabeth M
EM
Boyd
Gavin
G
D000818:Animals; D000906:Antibodies / Q000097:blood*; D000941:Antigens / Q000276:immunology; D001331:Automation; D001716:Bird Fancier's Lung / Q000175:diagnosis* / Q000276:immunology*; D001717:Birds / Q000276:immunology; D016022:Case-Control Studies; D002446:Celiac Disease / Q000276:immunology; D010856:Columbidae / Q000276:immunology; D021181:Egg Hypersensitivity / Q000276:immunology; D005470:Fluorometry / Q000379:methods* / Q000592:standards*; D006801:Humans; D007124:Immunoenzyme Techniques; D007074:Immunoglobulin G / Q000097:blood; D011233:Precipitin Tests; D012680:Sensitivity and Specificity; D013045:Species Specificity
D000906:Antibodies; D000941:Antigens; D007074:Immunoglobulin G