[The humoral and cellular factors of glomerular damage]

The present review summarizes current concepts on glomerular non-inflammatory and inflammatory immune injury. Non-inflammatory glomerular injury can be ascribed to mechanisms involving antibody alone, terminal component of complement (C5b-9) or cytokines having as primary target the glomerular epithelial cells. These mechanisms induce changes in cell cytoskeleton and in surface distribution of adhesion molecules leading to functional alterations which may account for loss of glomerular permselectivity. Inflammatory glomerular injury is mediated by neutrophils, macrophages, platelets and lymphocytes as well as by resident glomerular cells. Cell derived mediators include proteases, reactive oxygen species, cationic proteins, cytokines and growth factors that may variably affect recruitment of inflammatory cells, proliferation of resident glomerular cells and production of extracellular matrix. These alterations may determine proteinuria, impairment of renal function and eventually progression of glomerular injury to sclerosis. The inflammatory type of glomerular injury is mainly initiated by subendothelial-mesangial immune deposits and/or activation of cell mediated immunity. The role of factors such as the nature, intensity and persistence of initiating mechanisms, the types of inflammatory cells involved and the response of intrinsic glomerular cells, in expression and progression of glomerular injury are discussed.