Acknowledgements
We gratefully thank Mira Utriainen, Sanna Mäki, Minna Haanpää, Marja-Liisa Ollonen, Johanna Rintamäki, Hanna Valtonen, Riitta Santanen, Katri Keino, Alena Kaijalainen and Johanna Mustajoki for their expert technical assistance. Christel Pussinen and Mervi Nosa are thanked for their contribution to Finnish population sera collections. We also want to thank the anonymous patient for her help and collaboration throughout the study.
Funding: The study was supported by funds from the Finnish Institute for Health and Welfare (THL), Helsinki University Hospital (HUSLAB) and University of Helsinki. The funding organisations had no role in the study design, data collection and analysis, decision to publish or preparation of the manuscript.