TNF-? is a key cytokine involved in granulomatous inflammation. We presumed that serum TNF-? concentration (sTNF-?,) reflecting an active inflammatory process, may define an endotype of sarcoidosis.
Material and Methods: In a retrospective study of 125 sarcoidosis patients? demographic, radiological, functional, and biochemical parameters were categorized into numeric and quantitative variables. ELISA methods measured sTNF-?. The Kruskal-Wallis test was applied to investigate if the distribution of sTNF-? varies between categories of qualitative variables. Pearson?s correlations were calculated for quantitative variables. The cut-off value of sTNF-? was calculated to define TNF-? dependent endotype of sarcoidosis.
Results: sTNF-? concentration positively correlated with age, CXR progression, and the presence of extrapulmonary involvement (EI) and negatively correlated with lung function (LF) test and exercise ability (EA). sTNF-? was not associated with gender, symptoms, disease duration, radiological signs of fibrosis, and previous prednisone therapy. Patients with sTNF-? > 28.58 pg/ml had significantly higher serum concentrations of unspecific inflammatory markers, worse LF, significantly lower post-exercise Sp02, decreased EA, CXR progression, and EI compared to individuals with sTNF-? <28.58 pg/ml.
Conclusion: sTNF-? defines an endotype of radiologically progressive sarcoidosis with impaired LF, decreased EA, and EI. The cut-off value of 28.58 pg/ml discriminates between active, advanced sarcoidosis, and non-progressive forms. sTNF-? could aid in the individualized management of sarcoidosis.