[1] Natl Inst Hlth & Welf, Dept Vaccinat & Immune Protect, Helsinki, Finland
[2] Univ Helsinki, Biomedicum Stem Cell Ctr, FIN-00014 Helsinki, Finland
[3] Univ Turku, Immunogenet Lab, SF-20500 Turku, Finland
[4] Univ Eastern Finland, Dept Clin Microbiol, Kuopio, Finland
[5] Univ Helsinki, Hosp Children & Adolescents, FIN-00014 Helsinki, Finland
[6] Tampere Univ Hosp, Dept Pediat, Tampere, Finland