Association of polymorphisms in long pentraxin 3 and its plasma levels with COVID-19 severity.

COVID-19 is an infectious respiratory disease caused by SARS-CoV-2. Pentraxin 3 (PTX3) is involved in the activation and regulation of the complement system, demonstrating an important role in the pathogenesis of COVID-19. The aim was to evaluate the association of single nucleotide polymorphisms in PTX3 and its plasma levels with the severity of COVID-19. This is a retrospective cohort study, carried out between August 2020 and July 2021, including patients with confirmed COVID-19 hospitalized in 2 hospitals in the Northeast Region of Brazil. Polymorphisms in PTX3 (rs1840680 and rs2305619) were determined by real-time PCR. PTX3 plasma levels were measured by ELISA. Serum levels of interleukin (IL)-6, IL-8, and IL-10 were determined by flow cytometry. A multivariate logistic regression model was used to identify parameters independently associated with COVID-19 severity. P values  < 0.05 were considered significant. The study included 496 patients, classified as moderate (n = 267) and severe (n = 229) cases. The PTX3 AA genotype (rs1840680) was independently associated with protection against severe COVID-19 (P = 0.037; odds ratio = 0.555). PTX3 plasma levels were significantly associated with COVID-19 severity and mortality (P < 0.05). PTX3 levels were significantly correlated with IL-6, IL-8, IL-10, C-reactive protein, total leukocytes, neutrophil-to-lymphocyte ratio, urea, creatinine, ferritin, length of hospital stay, and higher respiratory rate (P < 0.05). Our results revealed a protective effect of the PTX3 AA genotype (rs1840680) on the development of severe forms of COVID-19. Additionally, PTX3 plasma levels were associated with the severity of COVID-19. The results of this study provide evidence of an important role of PTX3 in the immunopathology of COVID-19.