Aims: Members of the toll-like receptor (TLR) family have been shown to play important roles in inflammatory responses. Single-nucleotide polymorphisms (SNPs) altering receptor activity may either have detectable effects or might be without results due to compensatory mechanisms. We determined the genotype frequencies of functionally relevant SNPs in TLR2, 4 and 5 in critically ill patients (n=150) from a multidisciplinary surgical intensive care unit (ICU). The inflammatory response (procalcitonin, C-reactive protein, white blood count) and clinical classification (Acute Physiology and Chronic Health Evaluation Score II, Simplified Acute Physiology Score II, Sepsis-related Organ Failure Assessment) were monitored daily.
Results: The genetic polymorphisms correlate with neither development nor outcome of sepsis. No correlations were found between C-reactive protein or WBC and the investigated SNPs. In patients in the ICU with abdominal surgery and multiple trauma, the TLR2-R753Q SNP was associated with infection at ICU admission (p<0.01); and for carriers of the TLR4-D299G SNP, a trend was observed (p=0.0776). Patients with multiple trauma carrying the TLR4-D299G SNP displayed significantly higher levels of procalcitonin (p=0.0212).
Conclusions: None of the investigated SNPs clearly predicted outcome of sepsis-related multiorgan failure. TLR2-R753Q SNP may be a useful marker to identify patients with high risk to develop infections at ICU admission but should be validated in larger studies. Future SNP-arrays investigating predisposition for infection should include this SNP alone or in combination with other functionally relevant SNPs.