1. Department of Paediatrics; University of Tartu; Tartu Estonia
2. Tartu University Hospital; Tartu Estonia
3. Children's Hospital and Jorvi Hospital; University of Helsinki and Helsinki University Central Hospital; Helsinki Finland
4. Immunogenetics Laboratory; University of Turku; Turku Finland
5. Department of Clinical Microbiology; University of Eastern Finland; Kuopio Finland
6. Children's Hospital; University of Helsinki and Helsinki University Central Hospital; Helsinki Finland
7. Department of Paediatrics; Tampere University Hospital; Tampere Finland