The apoptotic death of neuroblastoma cells caused by serum from patients with insulin-dependent diabetes and neuropathy may be Fas-mediated. 
Immunoglobulins from patients with diabetic neuropathy are toxic to neuroblastoma cells.  The cell death has characteristics of apoptosis: condensed chromatin, shrunken cytoplasm, elevation of [Ca2+]i and DNA fragmentation.  N1E-115 cell membranes contain Fas, a regulator of apoptosis that recently has been shown to be involved in pancreatic beta-cell destruction leading to diabetes.  Fas-specific antibodies bind to the surface of N1E-115 cells and induce apoptosis.  Serum from patients with diabetic neuropathy block Fas-antibody binding.  We conclude that sera from patients with diabetic neuropathy contain an activator of Fas-regulated apoptosis that may contribute to the pathogenesis of diabetic neuropathy.