[1] Univ Leon, Inst Biomed, Transplantat Immunobiol Sect, E-24071 Leon, Spain
[2] Castilla & Leon Transplantat Reg Agcy, Leon Univ Hosp, Leon 24071, Spain
[3] Univ Hosp, Dept Med Specialties, Div Immunol & Allergy, Geneva, Switzerland
[4] Fac Med, Geneva, Switzerland