[Immunopathology of the kidney. Immunohistochemical findings in inflammatory kidney disease]

Abstract

The immunohistological evaluation of kidney biopsies is essential for the diagnosis of inflammatory lesions caused by immunological processes. It enables the differentiation between glomerulonephritis caused by the action of antibodies against glomerular basement membrane (autoimmune-glomerulonephritis) and glomerulonephritis caused by deposition of circulating immune complexeses. The larger group of immunecomplex-glomerulonephritides can further be differentiated behalf of the topography of immunoglobulin and complement deposits within the glomerulus. Some immunohistological findings correlate with histologically characterized glomerulonephritides (acute postinfectious, perimembranous, membrano-proliferative glomerulonephritis, dense deposits disease). Morphologically similar glomerular lesions e.g. autoimmune-glomerulonephritis, immune-complex-glomerulonephritis or IgA-nephropathy can be characterized according to their underlying immunopathogenesis. Since immunopathological lesions may occur at a time when histologically no or only minimal lesions are evident, as e.g. in perimembranous glomerulonephritis or in early stages of lupus nephritis immunohistological examinations should be performed as early as possible. Later in the course of glomerulonephritis secondary phenomena like nonspecific insudations of immunoglobulins or complement factors make interpretations difficult. Besides the definition of immunopathogenesis immunohistological examinations may lead to answer etiological and therefore therapeutical questions by the detection of antigens within immune complexes.