[1] Univ Cologne, Ctr Mol Med, Inst Genet, Dept Mouse Genet & Metab, D-50674 Cologne, Germany
[2] Univ Cologne, Inst Genet, Dept Mouse Genet & Inflammat, D-50674 Cologne, Germany
[3] European Mol Biol Lab, Mouse Biol Unit, I-000016 Monterotondo, Italy
[4] Heidelberg Univ, Inst Pathol, Heidelberg, Germany
[5] Harvard Univ, Sch Med, CBR Inst Biomed Res, Boston, MA 02115 USA