Post-COVID-19 Patients Who Develop Lung Fibrotic-like Changes Have Lower Circulating Levels of IFN-β but Higher Levels of IL-1α and TGF-β

Purpose: SARS-CoV-2 infection induces in some patients a condition called long-COVID-19, herein post-COVID-19 (PC), which persists for longer than the negative oral-pharyngeal swab. One of the complications of PC is pulmonary fibrosis. The purpose of this study was to identify blood biomarkers to predict PC patients undergoing pulmonary fibrosis. Patients and Methods: We analyzed blood samples of healthy, anti-SARS-CoV-2 vaccinated (VAX) subjects and PC patients who were stratified according to the severity of the disease and chest computed tomography (CT) scan data. Results: The inflammatory C reactive protein (CRP), complement complex C5b-9, LDH, but not IL-6, were higher in PC patients, independent of the severity of the disease and lung fibrotic areas. Interestingly, PC patients with ground-glass opacities (as revealed by chest CT scan) were characterized by higher plasma levels of IL-1 alpha, CXCL-10, TGF-beta, but not of IFN-beta, compared to healthy and VAX subjects. In particular, 19 out of 23 (82.6%) severe PC and 8 out of 29 (27.6%) moderate PC patients presented signs of lung fibrosis, associated to lower levels of IFN-beta, but higher IL-1 alpha and TGF-beta. Conclusions: We found that higher IL-1 alpha and TGF-beta and lower plasma levels of IFN-beta could predict an increased relative risk (RR = 2.8) of lung fibrosis-like changes in PC patients.

Automated summary

This study identified higher levels of CRP, C5b-9, and LDH in post-COVID-19 patients, which could predict the risk of pulmonary fibrosis. Moreover, increased levels of IL-1 alpha and TGF-beta, along with decreased levels of IFN-beta, were associated with an increased risk of lung fibrosis in these patients.