Gene Polymorphisms Not Tied to Flu Deaths in Young Adults
But increased risk of MRSA infection associated with low MBL2-producing genotypes
TUESDAY, Dec. 13 (HealthDay News) -- Influenza-related deaths among children and young adults are not associated with polymorphisms in the tumor necrosis factor (TNF) and mannose-binding lectin (MBL2) genes, according to a study published in the December issue of the U.S. Centers for Disease Control and Prevention's Emerging Infectious Diseases.
Jill M. Ferdinands, Ph.D., from the CDC in Atlanta, and colleagues compared the prevalence of eight polymorphisms in the TNF and MBL2 genes among 105 children and young adults with fatal influenza (fatal cases), with that of U.S. population-based prevalence estimates (reference sample). Subanalyses were conducted to investigate whether these polymorphisms correlated with sudden death and bacterial co-infection in fatal cases.
The investigators found that the genotype prevalence and minor allele frequencies did not differ between fatal cases and the reference sample. The risk of invasive methicillin-resistant Staphylococcus aureus (MRSA) co-infection increased significantly for fatal cases with low producing MBL2 genotypes, compared with those with high- and intermediate-producing MBL2 genotypes (odds ratio, 7.1). Limited analysis of TNF and MBL2 genes found no correlation between genetic variants and fatal influenza infection.
"We found no significant differences in allele frequencies or genotype prevalence for variants in the TNF and MBL2 genes between fatal influenza cases in patients <40 years old and a nationally representative reference sample. However, among the case-patients who died, most of whom died in childhood, variants of MBL2 responsible for low production of MBL were associated with MRSA co-infection," the authors write.