[1] Kantonsspital Bruderholz, Cent Labs, Bruderholz, Switzerland
[2] Ctr Hosp Lyon Sud, Immunol Lab, Lyon, France
[3] Univ Ziekenhuizen Leuven, Cent Klin Lab, Leuven, Belgium
[4] Vejle Sygehus, Klin Kem Adeling, Aarhus, Denmark
[5] Grp Hosp Pitie Salpetriere, Cent Biochim Lab, F-75634 Paris, France
[6] Guys & St Thomas Hosp, Dept Chem Pathol, London SE1 9RT, England