1. Division of Immuno-Haematology and Transfusion Medicine, Azienda Ospedaliera-Universitaria Policlinico, University of Palermo
2. Division of Clinical Pathology, ‘V. Cervello’ Hospital, Palermo
3. National Institute of Statistics, Palermo
4. Division of Pneumology II, ‘V. Cervello’ Hospital, Palermo, Italy