title: Urinary immunoglobulin G to albumin ratio and N-Acetyl-Beta-D-Glucosaminidase as early predictors of therapeutic response in ANCA-associated glomerulonephritis.
abstract: BACKGROUND
  The aim of our study was to evaluate the prognostic value of glomerular and tubular proteinuria and tubular enzymuria as early indicators of therapeutic response to induction therapy with i.v. pulse cyclophosphamide (CyC) and methylprednisolone (MP) in patients with antineutrophil cytoplasmic antibody (ANCA) associated glomerulonephritis.
  
  
  RESULTS
  An observational single-center study was conducted in 30 patients with ANCA-associated glomerulonephritis. Patients were divided into subgroups with good or poor response to CyC therapy according to clinical and laboratory parameters. The diagnosis of ANCA-associated glomerulonephritis was based on the Chapel-Hill disease definitions. Good response to induction therapy was significantly associated with higher absolute values of urine N-acetyl-beta-D-glucosaminidase (NAG) to creatinine ratio (above 14.83 microcat/mol) and urine immunoglobulin G (IgG) to albumin ratio (above 0.09) at the time of diagnosis, while albuminuria or proteinuria did not have any early predictive value. The remission of renal disease was anticipated as early as 3 months after introduction of induction therapy in patients with reduction of urine NAG to creatinine ratio below the baseline value and in patients with at least 24% rise in eGFR.
  
  
  CONCLUSIONS
  Urine IgG to albumin and urine NAG to creatinine ratio are better early predictors of treatment response in patients with ANCA-associated glomerulonephritis than proteinuria or albuminuria.
authors.affiliation: Department of Nephrology, University Medical Center Ljubljana, Ljubljana, Slovenia.
authors.forename: Marija
authors.initials: M
authors.lastname: Mravljak
authors.affiliation: Institute of Pathology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Alenka
authors.initials: A
authors.lastname: Vizjak
authors.affiliation: Institute of Pathology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Dusan
authors.initials: D
authors.lastname: Ferluga
authors.affiliation: Department of Nephrology, University Medical Center Ljubljana, Ljubljana, Slovenia.
authors.forename: Jernej
authors.initials: J
authors.lastname: Pajek
authors.affiliation: Department of Nephrology, University Medical Center Ljubljana, Ljubljana, Slovenia.
authors.forename: Damjan
authors.initials: D
authors.lastname: Kovac
authors.affiliation: Department of Nephrology, University Medical Center Ljubljana, Ljubljana, Slovenia.
authors.forename: Andrej
authors.initials: A
authors.lastname: Skoberne
authors.affiliation: Department of Nephrology, University Medical Center Ljubljana, Ljubljana, Slovenia.
authors.forename: Andreja
authors.initials: A
authors.lastname: Ales Rigler
authors.affiliation: Department of Nephrology, University Medical Center Ljubljana, Ljubljana, Slovenia.
authors.forename: Radoslav
authors.initials: R
authors.lastname: Kveder
authors.affiliation: Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Andrej
authors.initials: A
authors.lastname: Kosir
authors.affiliation: Department of Nephrology, University Medical Center Ljubljana, Ljubljana, Slovenia.
authors.forename: Jelka
authors.initials: J
authors.lastname: Lindic
mesh_terms: D000118:Acetylglucosaminidase / Q000652:urine*; D000368:Aged; D000419:Albuminuria / Q000175:diagnosis; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000276:immunology* / Q000378:metabolism; D015415:Biomarkers / Q000652:urine; D003520:Cyclophosphamide / Q000627:therapeutic use; D005260:Female; D005921:Glomerulonephritis / Q000175:diagnosis / Q000188:drug therapy* / Q000276:immunology / Q000652:urine*; D005938:Glucocorticoids / Q000627:therapeutic use; D006801:Humans; D007074:Immunoglobulin G / Q000652:urine*; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D008297:Male; D008775:Methylprednisolone / Q000627:therapeutic use; D008875:Middle Aged; D011379:Prognosis; D012709:Serum Albumin / Q000378:metabolism*; D016896:Treatment Outcome
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D015415:Biomarkers; D005938:Glucocorticoids; D007074:Immunoglobulin G; D007166:Immunosuppressive Agents; D012709:Serum Albumin; D003520:Cyclophosphamide; D000118:Acetylglucosaminidase; D008775:Methylprednisolone