[1] S Giovanni Dio Hosp, Immunol & Allergol Lab Unit, I-50143 Florence, Italy
[2] Univ Leuven, Dept Microbiol Immunol & Transplantat, B-3000 Leuven, Belgium
[3] Onze Lieve Vrouw Hosp, Dept Lab Med, B-9300 Aalst, Belgium
[4] S Giovanni Dio Hosp, Rheumatol Unit, I-50143 Florence, Italy
[5] Univ Florence, Dept Clin & Expt Med, I-50139 Florence, Italy
[6] Univ Hosp Leuven, Dept Lab Med, B-3000 Leuven, Belgium
[7] Univ Perugia, Dept Med & Surg, Rheumatol Unit, I-06122 Perugia, Italy