1. Department of Medical Microbiology, Turku University, Turku, Finland and DNAX Research Institute of Molecular and Cellular Biology, Human Immunology Department, Palo Alto, CA, USA
2. Department of Pediatrics, Turku University Hospital, Turku, Finland
3. Department of Medicine, Turku University Hospital, Turku, Finland,
4. National Public Health Institute, Turku, Finland