Abstract

Background: Community Acquired Pneumonia (CAP) is increasingly prevalent. Although most patients can be cured after antimicrobial treatment, some individuals may develop acute lung injury or fatal septic shock after rapid disease progression. Genetic variation in the form of Single Nucleoid Polymorphisms (SNPs) of key molecules in innate immunity are related to clinical outcome of Community Acquired Pneumonia (CAP). Pentraxin 3 (PTX3) is one of the key members of the acute-phase reactant superfamily and plays an important role against various diseases.

Objective: The purpose of the current study was to assess the association between SNP in the PTX3 gene andits association with the risk of CAP.

Methods: This is a retrospective case-control study conducted in a department of respiratory medicine of a single medical center. Patients who were diagnosed with CAP based on the criteria of the Chinese Thoracic Society between January 2018 and December 2019 were included as the CAP group. Then CAP cases were matched 1:1 by gender with non-infectious hospitalized patients from the same department during the same time. By using polymerase chain reaction sequencing, we detected the genotypes and determined the allele frequencies and haplotype distributions of three SNPs within the PTX3 gene (rs2305619, rs3816527, and rs1840680) in the CAP and control groups, and compared their associations with the risk of CAP.

Results: Three SNPs in both groups were consistent with Hardy-Weinberg Equilibrium (HWE). A strong linkage disequilibrium was detected between any pair of the SNPs (D’=0.85 for rs2305619 and rs3816527, D’=0.91 for rs2305619 and rs1840680, and D’=0.93 for rs3816527 and rs1840680, respectively). Although there was no significant difference between CAP and control groups for genotypic distribution and haplotype frequency, we determined that SNP rs1840680 AA homozygotes were associated with a lower risk of CAP in adults (OR, 0.32; 95% CI, 0.11-0.91;
p=0.03).

Conclusions: Our findings suggested that PTX3 SNP was associated with the risk of CAP in adults. Translationally, this could mean that a diagnostic method or kit could be developed for rapid detection of SNPs in clinics to reduce the risk of CAP, especially for immunocompromised patients.

Keywords: Community-acquired pneumonia; innate immunity; Pentraxin 3; single nucleotide polymorphisms; rs1840680