Predominance of influenza B/Yamagata lineage viruses in Bulgaria during the 2017/2018 season.

In this study, we investigated the antigenic and genetic characteristics of influenza viruses circulating in Bulgaria during the 2017/2018 season. The detection and typing/subtyping of influenza viruses were performed using real-time RT-PCR. Results of antigenic characterisation, phylogenetic and amino acid sequence analyses of representative influenza strains are presented. The season was characterised by the predominance of B/Yamagata viruses, accounting for 77% of detected influenza viruses, followed by A(H1N1)pdm09 (17%), B/Victoria (3.7%) and A(H3N2) (2.4%). The sequenced B/Yamagata, B/Victoria, A(H1N1)pdm09 and A(H3N2) viruses belonged to the genetic groups 3, 1A, 6B.1 and 3C.2a1, respectively. Amino acid analysis of B/Yamagata isolates revealed the presence of three changes in haemagglutinin (HA), eight changes in neuraminidase (NA) and a number of substitutions in internal proteins compared with the B/Phucket/3073/2013 vaccine virus. Despite the amino acid changes, B/Yamagata viruses remained antigenically related to the vaccine strain. B/Victoria isolates fell into a group of viruses with double deletion (Δ162-163) in HA1. Substitutions in HA and NA sequences of B/Victoria, A(H1N1)pdm09 and A(H3N2) viruses were also identified compared with the vaccine strains, including in antigenic sites. The results of this study confirm the genetic variability of circulating influenza viruses and the need for continual antigenic and molecular surveillance.

A promoter polymorphism in the CD14 gene is associated with elevated levels of soluble CD14 but not with IgE or atopic diseases.

BACKGROUND: A polymorphism in the promoter region of the CD14 gene, C-159T, has been shown to be associated with increased levels of soluble CD14 (sCD14) and decreased serum immunoglobulin E (IgE) and the expression of a more severe atopic phenotype in previous studies. METHODS: To test if these associations are consistently found in different populations and different age groups, we genotyped 2048 children of different age groups as well as 888 adults from different regions of Germany for the CD14 C-159T polymorphism. RESULTS: While an association between this promoter polymorphism and levels of sCD14 could be confirmed in our study population (CC: 1017 ng/ml vs TT: 1370 ng/ml, P = 0.03), no association between CD14 C-159T genotypes and IgE levels or the prevalence of atopic diseases was seen. CONCLUSIONS: The lack of association between CD14 genotypes and IgE as well as atopic outcomes in this large German study population seems to indicate that CD14 genotypes may not directly be involved in the development of allergies during childhood.