Electrophoretic methods for analysis of urinary polypeptides in IgA-associated renal diseases.
We evaluated the utility of SDS-PAGE/Western blot and CE coupled with MS (CE-MS) for detection of urinary polypeptide biomarkers of renal disease in patients with IgA-associated glomerulonephritides. In a reference cohort of 402 patients with various renal disorders and 207 healthy controls, we defined CE-MS patterns of renal damage and IgA nephropathy (IgAN). In a blinded analysis of a separate cohort of patients with IgAN (n = 10), Henoch-Schoenlein purpura (HSP) with nephritis (n = 10), and IgA-associated glomerulonephritis due to hepatitis C virus (HCV)-induced cirrhosis (n = 9), and healthy controls (n = 12), we compared SDS-PAGE/Western blot and CE-MS against clinical urinalysis for detection of urinary proteins/polypeptides. Urinalysis indicated proteinuria for 50, 90, and 33% of patients, respectively, and for none of the healthy controls. SDS-PAGE/Western blot showed urinary polypeptides abnormality for 90, 80, and 67% of patients, respectively, and for none of the healthy controls. CE-MS indicated a Renal Damage Pattern in 80, 80, and 100 of patients, respectively, and in 17% of healthy controls, with the more specific IgAN Pattern in 90, 90, and 1%, respectively, and in none of the healthy controls. Based on differences in CE-MS patterns, the disease mechanisms may differ among various IgA-associated glomerulonephritides. These exploratory findings should be evaluated in a prospective study with contemporaneous renal biopsy and urinary testing. If validated, it may be feasible to adapt the CE-MS methodology to develop novel tests to detect renal injury at earlier stages, assess clinical manifestations, and monitor responses to therapy in patients with IgA-associated renal diseases.
Julian
Bruce A
BA
Division of Nephrology, University of Alabama at Birmingham, Birmingham, AL 35294, USA. bjulian@uab.edu
Wittke
Stefan
S
Novak
Jan
J
Good
David M
DM
Coon
Joshua J
JJ
Kellmann
Markus
M
Zürbig
Petra
P
Schiffer
Eric
E
Haubitz
Marion
M
Moldoveanu
Zina
Z
Calcatera
Shannon M
SM
Wyatt
Robert J
RJ
Sýkora
Josef
J
Sládková
Eva
E
Hes
Ondrej
O
Mischak
Harald
H
McGuire
Brendan M
BM
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000652:urine; D001706:Biopsy / Q000379:methods; D002648:Child; D002675:Child, Preschool; D003404:Creatinine / Q000097:blood; D019075:Electrophoresis, Capillary / Q000379:methods*; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods*; D005355:Fibrosis / Q000276:immunology / Q000652:urine; D005922:Glomerulonephritis, IGA / Q000276:immunology / Q000652:urine*; D006526:Hepatitis C / Q000276:immunology / Q000652:urine; D006801:Humans; D011695:IgA Vasculitis / Q000276:immunology / Q000652:urine; D007070:Immunoglobulin A / Q000302:isolation & purification / Q000652:urine*; D013058:Mass Spectrometry; D008875:Middle Aged; D010455:Peptides / Q000302:isolation & purification / Q000652:urine*; D011237:Predictive Value of Tests; D011507:Proteinuria / Q000652:urine*; D012680:Sensitivity and Specificity
D015415:Biomarkers; D007070:Immunoglobulin A; D010455:Peptides; D003404:Creatinine