Impact of cytokines and chemokines on lung function after COVID-19: 3- and 6-month follow-up.

<bold>Background:</bold> COVID-19 has posed a global healthcare challenge, with treatments varying according to severity. While many patients recover, some experience persistent symptoms such as cough, shortness of breath, and exercise intolerance. <bold>Objective:</bold> To assess the long-term effects of cytokines and chemokines on inflammation and airway dysfunction in post-COVID-19 patients. <bold>Methods:</bold> We prospectively studied 154 hospitalized patients with moderate COVID-19 and examined them after discharge and at 3- and 6-month follow-ups. We measured serum levels of IL-2, IL-4, IL-6, CCL5/RANTES, CXCL8/IL-8, CXCL9/MIG, and CXCL10/IP10 as well as pulmonary function tests (PFT): FVC, FEV1, FEV1/FVC, MEF 25-50-75, and DLCO. The cytokine and chemokine concentrations were determined by the ELISA method, and PFT was conducted using the JAEGER MasterScreen. <bold>Results:</bold> PFT parameters remained constant throughout the observation period. IL-2, IL-4, CCL5, CXCL8, and CXCL9 levels increased significantly at the sixth month of follow-up, whereas IL-6 and CXCL10 decreased at the third month (p < 0.05). Significant correlations were found between cytokine levels and FEV1 and between chemokine levels and MEF 25-75 and DLCO. <bold>Conclusions:</bold> Associations between PFT parameters, especially DLCO, FEV1, MEF 25-75, and cytokine/chemokine levels suggest persistent bronchial inflammation, primarily in the small airways and lung parenchyma, after COVID-19 recovery.