[1] Univ Helsinki, Biomed Helsinki, FIN-00029 Helsinki, Finland
[2] TNO PG, Gaubius Lab, Leiden, Netherlands
[3] Univ Helsinki, Dept Lab Diagnost, Helsinki, Finland
[4] ORTON, Orthopaed Hosp, Invalid Fdn, Inst Res, Helsinki, Finland
[5] Univ Helsinki, Cent Hosp, Dept Med Invartes Med, Helsinki, Finland