[Fibrillary glomerulopathies].

Abstract

Fibrillary glomerulonephritis is characterized by the presence, mainly in the mesangium, of fibrils demonstrated by electron microscopy of the renal parenchyma. There are several varieties of this disease, depending on the size and, above all, the composition of these fibrils. Thus, fibrillary glomerulonephritis in which the fibrils are made of the normal glomerular basement membrane components can be distinguished from a more frequent variety in which the fibrils are composed of circulating proteins deposited in glomeruli. For a long time, amyloid glomerular nephropathy has been the sole representative of the latter variety, but we now know that, beside renal amyloidosis, there is a non-amyloid fibrillary glomerulonephritis the fibrils of which are made of monoclonal or non-monoclonal immunoglobulins. If it were confirmed that the principal member of this variety, described as immunotactoid glomerulopathy, is frequently associated with monoclonal gammapathy, it would represent, together with amyloidosis and light chain deposition, another variety of glomerular lesions which may occur in monoclonal gammapathy.