Background: Soluble TNF receptors (sTNFR1 and sTNFR2) are inhibitors of TNF and can block TNF bioactivity. TNF plays an important role in the development of extrinsic allergic alveolitis (EAA).
Objective: To evaluate whether sTNFR1 and sTNFR2 are locally increased in EAA.
Methods: We measured sTNFR1 and sTNFR2 in bronchoalveolar lavage fluid (BALF) and serum from nine EAA patients and 11 control subjects using an ELISA method.
Results: BALF sTNFR1 and sTNFR2 levels were 0.24+/- 0.04 ng/mL and 0.59+/-0.16 ng/mL in EAA patients, and thus significantly elevated in comparison with the controls (0.13+/-0.02 ng/mL and 0.08+/-0.04 ng/mL, both P<0.05). Serum sTNFR levels were not significantly different between the two groups. Both sTNFR1 and sTNFR2 concentrations in BALF correlated significantly with the lymphocyte percentage of BALF (r = 0.57 and 0.81, respectively).
Conclusion: The two alveolar sTNFRs, particularly sTNFR2, may be involved in the pathogenesis of EAA as counter-regulators of TNF.