The Prognostic Value of Lung Injury and Fibrosis Markers, KL-6, TGF-β1, FGF-2 in COVID-19 Patients

• Published in: Biomarker insights Vol. 17; p. 11772719221135443
• Main Authors: Karadeniz, Hazan, Avanoğlu Güler, Aslıhan, Özger, Hasan Selçuk, Yıldız, Pınar Aysert, Erbaş, Gonca, Bozdayı, Gülendam, Deveci Bulut, Tuba, Gülbahar, Özlem, Yapar, Dilek, Küçük, Hamit, Öztürk, Mehmet Akif, Tufan, Abdurrahman
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 2022; Sage Publications Ltd; SAGE Publishing
• Subjects: Alveoli; Biomarkers; Coronaviruses; COVID-19; Diagnosis; Fibrinogen; Fibroblast growth factor 2; Fibrosis; Growth factors; Inflammation; Lung diseases; Lymphocytes; Original Research; Prognosis; Serum levels; Severe acute respiratory syndrome coronavirus 2; Transforming growth factor-b1; computed tomography; fibroblast growth factor-2; Coronavirus disease 2019; biomarker; Krebs von den Lungen-6; transforming growth factor-beta1
• ISSN: 1177-2719; 1177-2719
• DOI: 10.1177/11772719221135443

Background: Biomarkers of lung injury and interstitial fibrosis give insight about the extent of involvement and prognosis in well-known interstitial lung diseases (ILD). Serum Krebs von den Lungen-6 (KL-6) reflects direct alveolar injury and, transforming growth factor-beta1 (TGF-β1) and fibroblast growth factor-2 (FGF-2) are principal mediators of fibrosis in ILD and in almost all fibrotic diseases. In this sense, we aimed to assess associations of these biomarkers with traditional inflammatory markers and clinical course of COVID-19. Methods: Patients with COVID-19 who had confirmed diagnosis with SARS-CoV-2 nucleic acid RT-PCR were enrolled and followed up prospectively with a standardized approach one month after diagnosis. Patients were divided into severe and non-severe groups according to National Institutes of Health criteria. Outcome was assessed for the requirement of intensive care unit (ICU) admission, long term respiratory support and death. Blood samples were collected at enrollment and serum levels of KL-6, TGF-β1, FGF-2 were determined by ELISA. Association between these markers with other prognostic markers and prognosis were analyzed. Results: Overall 31 severe and 28 non-severe COVID-19 patients were enrolled and were compared with healthy control subjects (n = 30). Serum KL-6 levels in COVID-19 patients were significantly higher (median [IQR]; 11.54 [4.86] vs 8.54 [3.98] ng/mL, P = .001] and FGF-2 levels were lower (median [IQR]; 76.84 [98.2] vs 101.62 [210.6] pg/mL) compared to healthy control group. A significant correlation was found between KL-6 values and CRP, fibrinogen, d-dimer and lymphocyte counts. However, we did not find an association between these markers and subsequent severity of COVID-19, mortality and long-term prognosis. Conclusions: Serum KL-6 levels were significantly elevated at the diagnosis of COVID-19 and correlated well with the other traditional prognostic inflammatory markers. Serum levels of principal fibrosis mediators, TGF-β1, FGF-2, were not elevated at diagnosis of COVID-19, therefore did not help to anticipate long term prognosis.