1. Medizinische Klinik und Poliklinik I, Hospital of the University of Munich, Campus Großhadern,1 and
2. Anatomische Anstalt,2 Ludwig-Maximilians-Universität, Munich, Germany, and
3. Institute for Human Gene Therapy, Department of Medicine and Molecular and Cellular Engineering, University of Pennsylvania and The Wistar Institute,3 and
4. Division of Pulmonary Medicine, Children's Hospital of Philadelphia,4 Philadelphia, Pennsylvania 19104