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.
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.
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
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.