Received January 11, 2008
Accepted on August 5, 2008

BASIC RESEARCH

Imatinib Suppresses Cryoglobulinemia and Secondary Membranoproliferative Glomerulonephritis

Masayuki Iyoda ^*, Kelly L. Hudkins ^*, Shirly Becker-Herman , Tomasz A. Wietecha ^*, Miriam C. Banas ^||, Shunhua Guo ^*, Almut Meyer-Bahlburg , Jolanta Kowalewska ^*, Gang Liu ^*, Steven F. Ziegler ^¶, David J. Rawlings ^**, and Charles E. Alpers ^*1

*Department of Pathology, University of Washington, Departments of Pediatrics and **Immunology, University of Washington School of Medicine, Seattle Children’s Research Institute, and ¶Immunology Program, Benaroya Research Institute at Virginia Mason, Seattle, Washington; Department of Nephrology, Showa University School of Medicine, Tokyo, Japan; and ||Department of Nephrology, University of Regensburg, Regensburg, Germany

¹ To whom correspondence should be addressed. E-mail: calp{at}u.washington.edu.

	Abstract

Imatinib is a receptor tyrosine kinase inhibitor that blocks the activity of c-Abl, c-Kit, and PDGF receptors. We tested the protective effects of imatinib in thymic stromal lymphopoietin transgenic mice, a model of cryoglobulinemia and associated membranoproliferative glomerulonephritis (MPGN), in which some glomerular manifestations likely result from PDGF receptor activation. Surprising, administration of imatinib beginning at weaning suppressed production of cryoglobulin, attenuating both the renal injury and systemic features of cryoglobulinemia. Flow cytometry suggested that inhibition of B cell development in the bone marrow likely caused the reduction in cryoglobulin production. In addition, administration of imatinib to thymic stromal lymphopoietin transgenic mice with established MPGN also diminished cryoglobulin production and reversed the renal and systemic lesions. These data suggest that treatment with imatinib may be a novel therapeutic approach for cryoglobulinemia and MPGN in humans.