Antigen-specific IgG antibodies in feather duvet lung.

ABSTRACT

BACKGROUND: Feather duvet lung (FDL) is a rare subgroup of bird fancier's lung (BFL). We were interested in determining antigen-specific IgG antibodies in patients with FDL and comparing them with those with BFL. MATERIAL AND METHODS: Specific IgG antibodies against goose and duck feathers, analysed with an automated fluorimetric enzyme immunoassay, were measured in healthy subjects (group A, n = 30), in patients with FDL (group B, n = 10) and with BFL (group C, n = 35); typical specific IgG antibodies of BFL in groups B and C. RESULTS: An optimal threshold value for antibodies against goose or duck feathers to differentiate patients with either BFL or FDL from healthy subjects was determined at 10.85 mg L(-1) for goose feathers and at 8.81 mg L(-1) for duck feathers, respectively. Specific IgG antibodies against goose feathers were significantly higher in group B compared with group C. A ratio of specific IgG antibodies against goose feathers and budgerigar antigens with a threshold value of 0.91 could discriminate between patients with FDL and BFL with a specificity of 97% and a sensitivity of 90%. CONCLUSIONS: We were able to demonstrate the significant difference in IgG antibodies in patients with FDL and BFL and their contribution to discriminate between these similar kinds of extrinsic allergic alveolitis.