Introduction
Coronavirus disease (COVID-19) first emerged in Wuhan, China, in December 2019, and it was found to be caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), a novel coronavirus. Genetic sequencing of the virus has shown that it is a betacoronavirus that is closely linked to the severe acute respiratory syndrome (SARS) virus (1). Coronaviruses are among the main pathogens that primarily target the human respiratory system. SARS-CoV and Middle East respiratory syndrome coronavirus (MERS-CoV) causes fatal infections. As a novel betacoronavirus, SARS-CoV-2 is more contagious. Although it has a lower mortality rate than SARS-CoV and MERS-CoV do, the severity of disease is more variable with SARS-CoV-2 (2).
Severe disease characterized by interstitial pneumonia develops in 10%–20% of patients (especially in elderly individuals and those with underlying comorbidities). Particularly, macrophage activation syndrome characterized by hyperferritinemia, hepatic dysfunction, and diffuse intravascular coagulation and rapidly developing acute respiratory distress syndrome (ARDS) characterized by high levels of acute phase reactants or septic shock may occur (3,4).
Periostin has been associated with many respiratory disorders. It has been recently shown to be an indicator of disease progression in idiopathic pulmonary fibrosis (5-7) and asthma (8). It is a matricellular protein. Matricellular proteins are nonstructural, extracellular matrix (ECM) proteins that are highly expressed at sites of injury or inflammation. They interact with other ECM proteins to mediate tissue remodeling, and they bind to growth factors and cytokines to modulate their activities (9). Expression of POSTN , the gene encoding human periostin, can be induced by the cytokines transforming growth factor beta (TGF-β), interleukin (IL)-4, and IL-13 (10,11). Periostin interacts with multiple molecules involved in signal cascades to modulate the expression of various genes such as those encoding collagen, chemokines, and TGF-β (12,13).
In this study, we aimed to investigate whether periostin could be a useful new biomarker in the follow-up and severity assessment of the disease in patients with COVID-19 pneumonia. In addition, this is the first study on periostin levels in patients with COVID-19.