Plasma levels of TNF-α and MMP-9 in patients with silicosis.

Objective: Silicosis is usually recognized at later stages of the disease, and early biomarkers for silicosis will be useful for timely diagnosis. We aimed at examining plasma levels of TNF-α and MMP-9, and correlation between these, in patients with different stages of silicosis in order to test suitability of these inflammatory factors as early biomarkers for silicosis.
Patients and Methods: TNF-α and MMP-9 were quantified by ELISA in plasma specimens from 30 healthy individuals (control group), 28 individuals exposed to silica dust but without clinical disease, and 30 patients with silicosis.
Results: Plasma levels of TNF-α and MMP-9 were increased in individuals exposed to silica dust (p < 0.05 vs. control individuals) and were further elevated in patients with silicosis (p < 0.05 vs. control individuals and individuals exposed to silica dust). There was a significant correlation between plasma levels of TNF-α and MMP-9 both in individuals exposed to silica dust (r = 0.696, p < 0.01) and patients with silicosis (r = 0.768, p < 0.01).
Conclusions: Plasma levels of TNF-α and MMP-9 are increased prior to development of clinically recognized silicosis, suggesting that these biomarkers are involved in the onset and development of silicosis. Combined detection of TNF-α and MMP-9 may be useful for early diagnosis of silicosis.