Arthritis & Rheumatism, Volume 60,
October 2009 Abstract Supplement
The 2009 ACR/ARHP Annual Scientific Meeting
Philadelphia October 16-21, 2009.
Urinary Biomarkers May Differentiate Between Children with ISN/RPS Class IV Versus Class V of Lupus Nephritis (LN)
Das1, Lena, Suzuki1, Michiko, Bennett1, Michael, Haines2, Kathleen A., Klein-Gitelman3, Marisa, Olson4, Judyann C., Onel5, Karen
Cincinnati Children's Hospital Medical Center, Cincinnati, OH,
University of Cincinnati, Cincinnati, OH
Hackensack Univ Med Ctr, Hackensack, NJ,
Children's Memorial Hospital, Chicago, IL,
Med Coll of Wisconsin, Milwaukee, WI,
Univ of Chicago, Chicago, IL,
Oklahoma University Health Science Ctr, Oklahoma City, OK,
Hospital for Sick Children and University of Toronto. Toronto, ON,
University Hospitals/Case Medical Center/Rainbow Babies and Children's Hospital. Cleveland, OH,
BC Childrens Hospital, Vancouver, BC,
Biopsy-proven LN occurs in up to 75% of all children with SLE. ISN/RPS classes of LN differ in major histological features, clinical manifestations and prognosis. Our aim was to identify urinary biomarkers that can differentiate between ISN/RPS class IV and class V in children with LN.
In this ongoing study, urine samples from children with LN ISN/RPS class IV (n=6) and pure class V (n=7) collected within 60 days of a kidney biopsy and those of controls with focal segmental glomerulosclerosis (n=4) were tested. Two proteomic methods were employed that reliably measure large and mid-molecular weight proteins, i.e. 2-dimensional gel electrophoresis (2-DGE) and surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS), respectively. Candidate biomarker proteins were selected if levels differed significantly when comparing class IV vs. V, class IV vs. controls, or class V vs. controls. The identity of relevant protein spots seen on 2-DGE was obtained by MALDI-TOF-MS/MS.
Using 2-DGE and MALDI-TOF-MS/MS, we found human serum albumin fragments (25kDa) and a1-B glycoprotein (60kDa) significantly over-expressed in class IV vs. class V LN. For SELDI-TOF-MS/MS four different chromatographic surfaces were tested; spectra were analyzed with ProteinChip Data Manager 3.07. The resulting urinary signature of mid-molecular weight proteins that differed between groups of samples based on robust and reproducible peaks is shown in the Table, with areas under the receiver operating characteristic curves > 0.7 (all p < 0.05).
We have identified two proteins and a urinary biomarker signature that appear to be significantly different between LN ISN/RPS class IV and class V. Further studies in larger patient groups, including adults with SLE, are needed to confirm our findings and to assess the diagnostic accuracy of these candidate biomarkers.
To cite this abstract, please use the following information:
Das, Lena, Suzuki, Michiko, Bennett, Michael, Haines, Kathleen A., Klein-Gitelman, Marisa, Olson, Judyann C., et al; Urinary Biomarkers May Differentiate Between Children with ISN/RPS Class IV Versus Class V of Lupus Nephritis (LN) [abstract]. Arthritis Rheum 2009;60 Suppl 10 :1527