Thermoactinomyces vulgaris, IgG Antibodies, Serum
Thermoactinomyces vulgaris is a causative agent of hypersensitivity pneumonitis (HP). Other causative microorganisms include Micropolyspora faeni and Aspergillus fumigatus. While the immunopathogenesis of HP is not known, several immune mechanisms are postulated to play a role, including both cellular and humoral mechanisms.(1)
Evaluating patients suspected of having hypersensitivity pneumonitis induced by exposure to this antigen
Elevated concentrations of IgG antibodies to Thermoactinomyces vulgaris are consistent with the diagnosis of hypersensitivity pneumonitis (HP) caused by exposure to this antigen.
Elevated concentrations of IgG antibodies to Thermoactinomyces vulgaris were found in a small number of sera from patients with HP (4%).(2)
IgG antibodies to Thermoactinomyces vulgaris are detectable in healthy individuals, and the presence of antibodies is not sufficient to establish the diagnosis of hypersensitivity pneumonitis (HP) caused by exposure to this antigen.
The levels of antibodies decrease following successful treatment of HP; but, elevated levels may persist for long periods.
0-12 years: < or =6.6 mg/L
13-18 years: < or =11.0 mg/L
>18 years: < or =23.9 mg/L
Clinical References Provides recommendations for further in-depth reading of a clinical nature
1. Fink JN, Zacharisen MC: Chapter 19: Hypersensitivity pneumonitis. In Allergy Principles and Practice. Vol 1. Fifth edition. Edited by E Middleton Jr, CE Reed, EF Ellis, et al. St. Louis, MO, Mosby Year Book Inc., 1998
2. Anderson E, Jacob GL, Roberts GD, Homburger HA: Comparative evaluation of enzyme immunoassay and immunodiffusion for detection of IgG antibodies to hypersensitivity pneumonitis antigens. Poster Presentation AAAAI Annual Meeting, San Diego, CA, March 3-8, 2000. J Allergy Clin Immunol 2000;105:S304