[1] Univ Turin, Headache Ctr, S Lazzaro Hosp, I-12051 Turin, Italy
[2] S Lazzaro Hosp, Main Lab, Turin, Italy
[3] San Giovanni Bosco Hosp, Hematol Unit, Turin, Italy
[4] Reg Serv Epidemiol, Alessandria, Italy
[5] Occupat Med Serv, Turin, Italy
[6] S Lazzaro Hosp, Dept Neurol, Turin, Italy
[7] S Lazzaro Hosp, Blood Transfus Serv, Turin, Italy
[8] S Lazzaro Hosp, Adm Med Off, Turin, Italy
[9] San Giovanni Bosco Hosp, Dept Clin Immunol, Turin, Italy