부산대학교 도서관

Infections with tick‐borne encephalitis virus (TBEV) may be asymptomatic or cause severe symptoms from the central nervous system, such as meningitis or encephalitis. A mutation in the chemokine receptor 5 (CCR5) gene has been associated with increased risk of TBE but can only explain a limited number of cases and investigations of further risk factors are clearly needed. To investigate the importance of the innate immune response, 128 Lithuanian TBE patients with meningitis or encephalitis, 77 patients with aseptic meningoencephalitis (AME) and 135 healthy controls were analyzed for three mutations: two in the toll‐like receptor 3 (TLR3) gene and one in the 2´‐5´ oligoadenylate synthetase 1 (OAS1) gene. While no association was found between the mutation in OAS1 and TBE, the genotype distribution of one of the mutations in TLR3, rs3775291, differed significantly between the TBE patients and the controls. 61%, 32% and 7% of the TBE patients (n=127) were carriers of the wild‐type/wild‐type, heterozygous and mutant/mutant genotype of TLR3 rs3775291 genotype respectively. The corresponding percentages for healthy controls (n=126) were 52%, 29% and 19% (P=0.02) and for AME patients (n=75) 47%, 32% and 21% (P=0.009). The wild‐type rs3775291 allele was more common among TBE patients than healthy controls (allele frequency 0.768 vs. 0.663, P=0.01), suggesting that functional TLR3 is a risk factor for severe TBEV infection.