Brief Reports Lack of Effects of the Genetic Polymorphisms of Interleukin-10 in Clinical Outcomes of COVID-19 Mariana Avendan ˜ o-Fe ´ lix, 1 Luis Antonio Ochoa-Ramı ´rez, 2 Rosalı ´o Ramos-Paya ´ n, 1 Maribel Aguilar-Medina, 1 Alfredo Ayala-Ham, 3 Horacio Rendo ´ n-Aguilar, 2 Erik Liza ´ rraga-Verdugo, 1 Felipe Peraza-Garay, 4 Juan Jose ´ Rı ´os-Tostado, 2,3 and Jesu ´ s Salvador Velarde-Fe ´ lix 2,3, * Abstract Interleukin-10 (IL-10) gene polymorphisms have been associated with severity and outcomes in patients with respiratory and nonrespiratory viral infections. The aim of this study was to assess whether rs1800871 and rs1800872 polymorphisms of IL-10 gene are associated with the clinical outcomes of COVID-19 in a Mexican population. Study subjects were 193 COVID-19 patients. The genotyping was carried out with real-time PCR and serum IL-10 levels were measured with enzyme-linked immunosorbent assay. Logistic regression analysis was used for analysis association with clinical outcomes. There was no evidence of an association between alleles, genotypes, or haplotypes frequencies between patient groups according to severity and outcomes. The rs1800871 and rs1800872 polymorphisms might not be genetic risk factors for severity and mortality for COVID-19 in Mexican mestizos patients from northwest Mexico. Keywords: IL-10 gene, polymorphisms, severity, COVID-19, Mexican Introduction A n equilibrium between proinflammatory and anti- inflammatory cytokines is required to achieve a stable and healthy immune response; however, in some infectious diseases an exacerbated synthesis of these can occur (7). This phenomenon, named ‘‘storm cytokine,’’ has been considered the main responsible immunopathological process of a more severe clinical course and cause of death in patients with severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2)/ COVID-19 (12). The first clinical and laboratory reports of COVID-19 showed an immunological disturbance, being the cytokines interleukin (IL)-2, IL-6, IL-7, IL-10, tumor necrosis factor (TNF)-a, granulocyte colony-stimulating factor (G- CSF), interferon gamma-induced protein 10 (IP-10), monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein 1A (MIP1A) associated with a worsening of the disease (4,6,15). In subsequent investigations, IL-10 was considered an excellent biomarker to predict unfavorable prognosis (8,15,16,29) and a risk factor for death (30). IL-10 is a cytokine secreted by most immune system cells in response to antigen; it regulates the inflammatory response inhibiting the synthesis of others cytokines, for example IL-2, IL-3, interferon-g (IFN-g), and granulocyte-macrophage colony-stimulating factor (GM- CSF) by T helper cells (21). Its involvement in several respi- ratory and nonrespiratory infections is very well documented (9,17,19). Genetic variation in the IL-10 gene is associated with risk of infection with influenza A/H3N2 (24), severity and fa- tality by influenza A(H1N1)pdm09 (7,19), severe rhinovirus bronchiolitis (10), predisposition to hepatitis C and tick- borne encephalitis viruses (2), and risk of HPV-associated cervical cancer development (17), in different populations. In this study, we hypothesized that IL-10 gene variation may be associated with COVID-19 severity considering IL-10 is a pivotal cytokine in antiviral action and inflammation regulation. Materials and Methods Subjects and definitions Patients were recruited from Hospital General de Culia- can and Hospital Civil de Culiacan, between March 2020 and June 2020. We enrolled 193 hospitalized patients with laboratory-confirmed SARS-Cov-2 RNA detection, whose clinical data and whole blood samples were collected. The 1 Facultad de Ciencias Quı ´mico Biolo ´gicas Universidad Auto ´noma de Sinaloa (Z. C: 80013), Culiaca ´n, Mexico. 2 Hospital General de Culiaca ´n, ‘‘Bernardo J Gaste ´lum,’’ Secretaria de Salud de Sinaloa (Z.C: 80230), Culiaca ´n, Mexico. 3 Facultad de Biologı ´a, Universidad Auto ´noma de Sinaloa, Culiaca ´n, Mexico. 4 Centro de Investigacio ´n y Docencia en Ciencias de la Salud (Z.C: 80030), Culiaca ´n, Mexico. *ORCID ID (https://orcid.org/0000-0002-0692-9297). VIRAL IMMUNOLOGY Volume 34, Number 8, 2021 ª Mary Ann Liebert, Inc. Pp. 567–572 DOI: 10.1089/vim.2021.0022 567 Downloaded by 34.227.83.32 from www.liebertpub.com at 10/16/21. For personal use only.