Relative to control-treated Schwann cells, both human and rat Schwann cells exposed to CIDP patient sera displayed decreased p57kip2, c-Jun, brain-derived neurotrophic factor (BDNF), and glial cell line-derived neurotrophic factor (GDNF) mRNA expression, an upregulation of nerve growth factor (NGF) mRNA, and a reduction in granulocyte-macrophage colony-stimulating factor (GM-CSF). This evidence concerns the gene GDNF and chronic inflammatory demyelinating polyradiculoneuropathy.