ARDS severity in COVID-19: a case-control study of laboratory biomarkers and IL-10 SNP analysis

Acute respiratory distress syndrome (ARDS), which is often observed in severe cases of coronavirus disease 2019 (COVID-19), is known to be a major contributor to higher mortality rates. This study assesses how hematological parameters, inflammatory biomarkers, cytokines, and the -1,082 A/G polymorphism are associated with ARDS severity in COVID-19 patients.

Following exclusions, a 6-month prospective case-control study included 82 healthy controls (HCs) and 158 COVID-19 patients with varying severities of ARDS (mild: 73, moderate: 53, and severe: 32). Blood samples were collected at admission, and laboratory biomarkers were assessed using various methods. Statistical analyses included one-way analysis of variance with Tukey's test for group comparisons, Pearson correlation, and receiver operating characteristic curve for analyzing independent associations with COVID-19 severity. Multiple linear regression and chi-square tests were used to evaluate quantitative outcomes and categorical associations, respectively.

Severe ARDS patients exhibited higher C-reactive protein (CRP) levels compared to HCs. Compared to HCs, patients with moderate and severe ARDS had higher neutrophil to lymphocyte ratio (NLR), neutrophil counts, tumor necrosis factor-alpha, and interleukin-10 (IL-10), as well as lower lymphocyte counts and reduced partial pressure of oxygen/fraction of inspired oxygen (PaO₂/FiO₂) ratio. IL-10, body mass index, CRP, and NLR were associated with reduced PaO₂/FiO₂ ratio. IL-10 and CRP had the highest area under curve values toward ARDS severity. COVID-19 patients possessing the -1,082 A/G single nucleotide IL-10 GG and GA genotypes and the G allele presented with less severe ARDS.

Hematological indices (neutrophil count and NLR), CRP, and serum IL-10 hold promise in monitoring ARDS severity in COVID-19 patients. In addition, COVID-19 patients with GG and AG genotypes and the G allele of the IL-10 gene's-1,082 A/G polymorphism experience less severe ARDS. This highlights the potential protective role of IL-10 genetic variation in modulating the severity of inflammatory responses during severe acute respiratory syndrome-coronavirus-2 infection and may serve as a useful genetic marker for risk stratification in clinical settings.