Immunological mechanisms

The primary glomerulonephritides and many of the secondary glomerulonephritides are caused by the presence of immunoglobulin within the glomerulus and are, therefore, said to be immune mediated (Fig. 3.55.1). The processes involved are only partially understood. It is helpful to think of them in two main groups: immune complex deposition and nephrotoxic antibody.

Fig. 3.55.1 The three main types of immune-mediated glomerular injury. The final common pathway is activation of complement and inflammatory cells. (A) Circulating immune complexes are trapped in the glomeruli. (B) Antibodies to a ‘planted’ antigen cause in-situ immune complex formation. (C) Nephrotoxic antibody: antiglomerular basement membrane immunoglobulin binds to the basement membrane in a linear fashion.