1 Internal Medicine, Hospital Universitario Central de Asturias, Oviedo, Spain.
2 Internal Medicine, Hospital Valle del Nalón, Langreo, Spain.
3 Respiratory Department, Hospital Universitario Central de Asturias, Oviedo, Spain.
4 Systemic Autoinmmune Diseases Unit, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Hospital Universitario Central de Asturias, Oviedo, Spain.