The Impact of Surfactant Protein‐D Gene Polymorphism on COVID‐19 Clinical Outcomes

Background COVID‐19, caused by the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), presents a broad spectrum of clinical manifestations, ranging from asymptomatic cases to severe, life‐threatening respiratory complications. Pulmonary surfactant‐associated protein D (SP‐D) is a critical component of pulmonary immune defense. The objective of this study was to investigate the association between a specific single‐nucleotide polymorphism (SNP) in the SP‐D gene, designated as rs721917 (C/T Met31Thr), and its potential impact on susceptibility to and severity of COVID‐19. Methods This retrospective case–control study enrolled 135 participants, including 111 confirmed COVID‐19 patients and 24 asymptomatic or presymptomatic individuals, who were classified into five subgroups. Addressing a significant research gap, we identified the C/T polymorphism (rs721917, T > C) of the SP‐D gene within the Iranian population using the tetra‐amplification refractory mutation system polymerase chain reaction (T‐ARMS PCR) method. Results Statistical analysis showed a significant association between the SP‐D rs721917 TT genotype and T allele with increased COVID‐19 severity and hospitalization risk. The TT genotype was more frequent in ICU and CCU‐admitted patients compared to the CC genotype ( p < 0.05) and was linked to higher hospitalization rates overall. However, no significant correlation was found with mortality rates or patients' age. Conclusion These findings suggest that variations at the rs721917 locus within the SFTPD gene may provide valuable insights into the heterogeneity of COVID‐19 outcomes across different populations, thereby offering potential for enhanced diagnostic and prognostic strategies.