1. Department of Dermatology, Johns Hopkins Medical Institutions, Baltimore, MD 21287, USA.
2. Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD 21287, USA.
3. Department of Otolaryngology, Johns Hopkins Medical Institutions, Baltimore, MD 21287, USA.
4. Department of Surgery, Johns Hopkins Medical Institutions, Baltimore, MD 21287, USA.
5. Department of Oncology, Johns Hopkins Medical Institutions, Baltimore, MD 21287, USA.
6. Department of Immunobiology, Yale University, New Haven, CT 06519, USA.