SP-A1, SP-A2 and SP-D gene polymorphisms in severe acute respiratory syncytial infection in Chilean infants

Area of Science:

• Immunogenetics
• Pediatric Infectious Diseases
• Respiratory Medicine

Background:

• Respiratory syncytial virus (RSV) is a major cause of infant acute lower respiratory tract infections (ALRI).
• Host genetic factors are implicated in the severity of RSV-ALRI.
• Surfactant proteins SP-A1, SP-A2, and SP-D play roles in innate immunity and lung defense.

Purpose of the Study:

• To investigate the association between single nucleotide polymorphisms (SNPs) in SP-A1, SP-A2, and SP-D genes and the severity of RSV disease in infants.
• To identify potential genetic biomarkers for predicting severe RSV infection outcomes.

Main Methods:

• A prospective study comparing allele and genotype frequencies of SP-A1, SP-A2, and SP-D SNPs in RSV-infected infants and healthy blood donors.
• Statistical analysis using chi-squared tests, Armitage's trend test, and Unphased 3.0 for association and haplotype analysis.
• Infant disease severity was categorized using a strict scoring system.

Main Results:

• No significant differences in SP-A1 allele or genotype frequencies were observed, but intragenic SP-A1 haplotypes differed between groups (p=0.0021).
• The Thr(11) allele of SP-D was more frequent in RSV-infected infants (p=0.028), particularly those with severe disease (p=0.046).
• Specific SP-D haplotypes, including Thr(11)-Thr(160)-Ser(270), were significantly associated with severe and moderate RSV disease (p<0.00001).

Conclusions:

• Certain SP-D gene variants and haplotypes are associated with increased susceptibility to severe RSV infection in infants.
• These findings highlight the potential of SP-D as a genetic biomarker for RSV disease severity.
• Further local studies are recommended to validate these genetic biomarkers for clinical application.