Medical Officer National Cancer Institute (Maryland/USA 1965)
Leiter Immunpathologisches Labor (Köln 1972)
Habilitation (Köln 1973)
Professor für Allgemeine Pathologie und pathologische Anatomie, insbesondere Immunpathologie (Köln 1974-2000)
Chairman Internationales Institut für Immunpathologie Inc. (1989)
Visiting Professor (Houston/Texas 1990)
Professor of Medicine and Pathology (Houston/Texas 2000-2010)
Adjunct Professor of Pathology (Houston/Texas 2010-2014)