1. Department of DermatologyCharitéHumboldt University Berlin D-10117 Germany
2. Growth Factor and Regeneration GroupMax-Delbrück Center for Molecular Medicine Berlin D-13122 Germany
3. Hoechst Marion Roussel Inc. Bridgewater New Jersey 08807 USA
4. Institute of ImmunologyFree University Berlin D-12203 Germany
5. Institute of Laboratory MedicineCharitéCampus Virchow ClinicHumboldt University Berlin D-10117 Germany