title: Proteomic analysis of Class IV lupus nephritis.
abstract: BACKGROUND
  There have been several attempts to standardize the definition and increase reproducibility in classifying lupus nephritis (LN). The last was made by the International Society of Nephrology and Renal Pathology Society in 2003 where the introduction of Class IV subcategories (global and segmental) was introduced.
  
  
  METHODS
  We investigated whether this subdivision is important using a proteomics approach. All patients with renal biopsies along with their clinical outcome of LN were identified and regrouped according to the above 2003 classifications. Fresh-frozen renal biopsies of Class IV LN (global and segmental), antineutrophil cytoplasmic antibody-associated vasculitis and normal tissue were analyzed using two-dimensional gel electrophoresis (2-DE) and mass spectrometry. Differentially expressed proteins were identified and subjected to principal component analysis (PCA), and post hoc analysis for the four sample groups.
  
  
  RESULTS
  PCA of 72 differentially expressed spots separated Class IV global and Class IV segmental from both normal and antineutrophil cytoplasmic antibody-associated vasculitis (ANCA). The 28 identified proteins were used in a post hoc analysis, and showed that IV-global and IV-segmental differ in several protein expression when compared with normal and ANCA. To confirm the proteomic results, a total of 78 patients (50 Class IV-Global and 28 Class IV-Segmental) were re-classified according to 2003 classification. There was no difference in therapy between the groups. The renal survival and patient survivals were similar in both groups.
  
  
  CONCLUSIONS
  There is no strong evidence to support a different outcome between the two subcategories of Class-IV LN and, they should thus be treated the same until further studies indicate otherwise.
authors.affiliation: Proteomics Unit, Stem Cell and Tissue Re-Engineering Program, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.
authors.forename: Ayodele
authors.initials: A
authors.lastname: Alaiya
authors.affiliation: Department of Pathology, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.
authors.forename: Lina
authors.initials: L
authors.lastname: Assad
authors.affiliation: Nephrology Section, Department of Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.
authors.forename: Dania
authors.initials: D
authors.lastname: Alkhafaji
authors.affiliation: Proteomics Unit, Stem Cell and Tissue Re-Engineering Program, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.
authors.forename: Zakia
authors.initials: Z
authors.lastname: Shinwari
authors.affiliation: Department of Pathology, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.
authors.forename: Hadeel
authors.initials: H
authors.lastname: Almana
authors.affiliation: Department of Biostatistics and Epidemiology, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Shoukri
authors.affiliation: Nephrology Section, Department of Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.
authors.forename: Lutfi
authors.initials: L
authors.lastname: Alkorbi
authors.affiliation: Nephrology Section, Department of Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.
authors.forename: Hossamaldin Galal
authors.initials: HG
authors.lastname: Ibrahim
authors.affiliation: Nephrology Section, Department of Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia Internal Medicine Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt.
authors.forename: Mohamed Said
authors.initials: MS
authors.lastname: Abdelsalam
authors.affiliation: Nephrology Division, Department of Medicine, New York University Medical Center, NY, USA.
authors.forename: Edward
authors.initials: E
authors.lastname: Skolnik
authors.affiliation: Proteomics Unit, Stem Cell and Tissue Re-Engineering Program, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia Transplantation Research Center, Renal Division, Children's Hospital Boston and Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Chaker
authors.initials: C
authors.lastname: Adra
authors.affiliation: Proteomics Unit, Stem Cell and Tissue Re-Engineering Program, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia Nephrology Section, Department of Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia Nephrology Division, Department of Medicine, New York University Medical Center, NY, USA Nephrology Section, Department of Medicine, MBC-46, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.
authors.forename: Mamdouh
authors.initials: M
authors.lastname: Albaqumi
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008181:Lupus Nephritis / Q000145:classification / Q000378:metabolism* / Q000473:pathology; D008297:Male; D025341:Principal Component Analysis; D011379:Prognosis; D020543:Proteome / Q000378:metabolism*; D040901:Proteomics / Q000379:methods*; D012008:Recurrence; D012189:Retrospective Studies; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D015415:Biomarkers; D020543:Proteome
keywords: global-segmental; lupus-nephritis; profiles; protein-expression; proteomics; renal-biopsies