1. Institute of Molecular MedicineUniversity of Düsseldorf D‐40225 Düsseldorf Germany
2. Department of Immunology and Cell BiologyUniversity of Münster D‐48149 Münster Germany
3. Institute for Chemistry and BiochemistryUniversity of Bern CH‐3012 Bern Switzerland
4. Department of Internal MedicineUniversity of Tübingen D‐72076 Tübingen Germany