MPO and ganglioneuroma: We and others have shown that deposited extracellular MPO can be recognized by MPO-specific CD4+ T cells that in turn initiate cell-mediated glomerular injury characterized by DTH effectors, including the glomerular recruitment of M1 macrophages and the deposition of fibrin, features of GN that are prominent in human and murine anti-MPO GN (46, 47).