[3] MGRS disorders also have a greater than 90% rate of recurrence if the monoclonal gammopathy is not eliminated either before or immediately after a renal transplant.
[3] There are several separate conditions designated as MGRS which are associated with kidney damage (either directly or indirectly) due to monoclonal immunoglobulins (M proteins).
These AL light chains are misfolded leading to the disordered deposition of amyloid multimers and fibrils in the glomeruli and blood vessels of the kidney.
[3] Light microscopy findings in AL, AH or AHL amyloidosis include acellular deposits in the glomeruli and blood vessels that stain pale eosinophilic, Congo red positive and the presence of apple green birefringence on polarized light.
The lesions stain positive for the Ig (usually IgG) as well as complement; leading to granular immunofluorescent deposits in the mesangium and glomerular basement membrane.
[3] Monoclonal immunoglobulin deposition disease (MIDD) involves light chains with unusual characteristics of the variable domain (such as a positive charge, abnormal glycosylation, hydrophobic residues) depositing in the tubular, vascular or glomerular basement membranes of the nephron.
In light microscopy it presents as a membranoproliferative or endocapillary proliferative glomerulonephritis with intracapillary monocytes and immune deposits that stain positive for PAS.
[4] In a subtype of cryoglobulinemic glomerulonephritis known as crystalglobulinemia; monoclonal immunoglobulins may precipitate in the small arterioles and capillaries of the glomeruli when exposed to colder temperatures causing endothelial injury and microthrombi.
[1] The monoclonal antibody against the plasma cell surface protein CD38 daratumumab may also be used with very high efficacy against AL amyloidosis.
With CD20 expressing B-cells and lymphoplasmacytic clones; rituximab is the preferred treatment and it can be combined with dexamethasone and cyclophosphamide.
[1] Overall mortality of the various MGRS disorders is generally less than that of multiple myeloma, but light chain amyloidosis (AL type) with cardiac involvement is associated with rapid progression to death.