Focal glomerulonephritis shows pathologic involvement of some glomeruli, while the others have a normal aspect. It occurs in many different diseases as systemic lupus erythematosus, Schonlein Henoch syndrome, the Goodpasture syndrome and recurrent hematuria. Although focal by light microscopy, immunoglobulins are present in all glomeruli, as revealed by immunofluorescence techniques. There are clearly several different pathogenetic mechanisms and the factors which determine the focal nature of the entity are poorly understood. The widespread distribution of immunoglobulins shows that the condition is focal only in so far as the response to the immunologic stimulus is concerned. As an explanation, it has been suggested that in certain instances there is a primary deposition of immune complexes in the mesangium of the glomerulus. In this case there will be no injury to the capillary loops because the complexes are confined to the mesangium. If the complexes are laid down so rapidly that their mass exceeds the capacity of the mesangium to accommodate them, some will accumulate in the loop wall and produce a local or segmental lesion. The degree of loop involvement varies from one glomerulus to another so that a focal as well as segmental lesion will be produced. There are undoubtedly many factors that determine why some complexes localize in the mesangium. Size is one of these factors. In rabbits given repeated injections of bovine serum albumin large complexes of over 1 x 106 daltons give rise to a predominantly mesangial pattern which may develop a focal glomerulonephritis by light microscopy.
|Original language||English (US)|
|Number of pages||12|
|State||Published - Dec 1 1975|
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