1. From the Department of Anatomical Pathology (Drs Gómez-Román and Val-Bernal) and Service of Immunology (Drs Ocejo-Vinyals, Sánchez-Velasco, and Leyva-Cobián), Marqués de Valdecilla University Hospital, Instituto Nacional de la Salud, Medical Faculty, University of Cantabria, Santander, Spain.
2. Drs Gómez-Román and Ocejo-Vinyals have contributed equally to this work, and both must be considered as first authors.Reprints: J. Fernando Val-Bernal, MD, Departamento de Anatomía Patológica, Hospital Universitario Marqués de Valdecilla, Avda Valdecilla s/n, 39008 Santander, Spain.