Monoclonal gammopathy: significance and possible causality in renal disease.
BACKGROUND
Patients with monoclonal gammopathy can develop a variety of related renal lesions or possibly have kidney disease unrelated to their monoclonal gammopathy. We characterized the spectrum of renal diseases associated with monoclonal gammopathy and renal diseases.


METHODS
Patients who underwent renal biopsy and had monoclonal gammopathy on serum and/or urine electrophoresis and/or had a renal biopsy diagnosis related to paraprotein (cryoglobulinemic glomerulonephritis [CG], monoclonal immunoglobulin deposition disease [MIDD], light chain cast nephropathy [CN], or light chain amyloidosis [AL]) were identified.


RESULTS
One hundred twenty-one patients met the inclusion criteria and were classified as having renal disease related or unrelated to monoclonal gammopathy. Among 66 cases of renal disease related to monoclonal gammopathy, diagnoses were CG (30.3%), MIDD (28.8%), CN (19.7%), AL (19.7%), and CN plus MIDD (1.5%). Among patients with monoclonal gammopathy in serum and/or urine (n = 87), 32 patients (36.8%, included in listing above) had related renal disease. Among 55 patients with monoclonal gammopathy and unrelated renal disease (63.2% of all patients with monoclonal gammopathy), various lesions were found, including diabetic nephropathy (18.1%), focal segmental glomerulosclerosis (18.1%), arterionephrosclerosis (12.7%), membranous glomerulonephritis (9.0%), minimal change disease (7.3%), various immune complex diseases, interstitial nephritis, or nonspecific changes.


CONCLUSIONS
The majority of patients with serum and/or urine monoclonal gammopathy who undergo renal biopsy have disease unrelated to monoclonal gammopathy deposition. This likely reflects the high frequency of monoclonal gammopathy of undetermined significance in older patients and the frequent use of serum and/or urine protein electrophoresis as screening tools in adult patients with renal disease.
Paueksakon
Paisit
P
Department of Pathology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
Revelo
Monica P
MP
Horn
Robert G
RG
Shappell
Scott
S
Fogo
Agnes B
AB
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000686:Amyloidosis / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D001161:Arteriosclerosis / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D001706:Biopsy; D003449:Cryoglobulinemia / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D003450:Cryoglobulins / Q000032:analysis; D004586:Electrophoresis / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000032:analysis; D007674:Kidney Diseases / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010265:Paraproteinemias / Q000150:complications* / Q000378:metabolism / Q000473:pathology; D010266:Paraproteins / Q000032:analysis; D012189:Retrospective Studies
D003450:Cryoglobulins; D007147:Immunoglobulin Light Chains; D010266:Paraproteins