[1] ASO S Giovanni Battista Torino, Div Pneumol, I-10126 Turin, Italy
[2] ASO S Giovanni Battista Torino, Div Thorac Surg, I-10126 Turin, Italy
[3] ASO S Giovanni Battista Torino, Div Virol, I-10126 Turin, Italy
[4] ASO S Giovanni Battista Torino, Div Cardiac Surg, I-10126 Turin, Italy
[5] ASO S Giovanni Battista Torino, Dept Pathol, I-10126 Turin, Italy