Heisenberg Fellowship no. DFG NO454/3-I from the Deutsche Forschungsgemeinschaft (to NN). • 4-13 Reprints not available. Address correspondence to N Novak, Department of Dermatology, University of Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany. E-mail: • Received July 3, 2006. • Accepted Novembe