title: Diagnostic value of brush border enzymes of the proximal renal tubules in rheumatoid arthritis.
abstract: BACKGROUND
  Proximal tubules of the kidney have a dominant function in the excretion of different enzymes in the urine. These enzymes can be used as markers for secondary renal damage under the action of different diseases, medicines, and toxins. The aim of this study was to evaluate the values of alanine aminopeptidase (AAP), gamma-glutamyl transferase (gamma-GT), and beta2 microglobulin (beta2m) in urine of patients with untreated rheumatoid arthritis (RA) and to define the possible association between untreated rheumatoid arthritis and tubular function at the brush border region.
  
  
  METHODS
  We used a kinetic assay for AAP, standard methods by the International Federation for Clinical Chemistry (IFCC) for gamma-GT and Microparticle Enzyme Immunoassay (MEIA), (Abbott A(x)SYM System) for the determination of beta2m in urine of 70 participants (35 untreated RA patients and 35 healthy volunteers (HC)).
  
  
  RESULTS
  From the total of 35 RA patients, AAP enzymuria was found in 24 patients with test sensitivity (68.57%), gamma-GT in 16 patients with test sensitivity (45.71%), while the presence of urinary beta2m was found in a very low percentage of cases. Out of 18 rheumatoid factor (RF) negative patients, 14 patients were AAP and 10 patients were gamma-GT positive, while the presence of beta2m in urine was not detected. Among 17 RF positive RA patients, the presence of AAP and gamma-GT was noticed in 10 and 6 patients, respectively, while the presence of beta2m in urine was not detected.
  
  
  CONCLUSIONS
  In conclusion, AAP had a higher sensitivity than gamma-GT and beta2m in detection of asymptomatic renal lesions in untreated RA.
authors.affiliation: Department of Rheumatology, University Clinical Center, Skopje, R. Macedonia. drspasovski@yahoo.co.uk
authors.forename: Dejan
authors.initials: D
authors.lastname: Spasovski
authors.forename: Jelka
authors.initials: J
authors.lastname: Masin-Spasovska
authors.forename: Marina
authors.initials: M
authors.lastname: Nada
authors.forename: Jordan
authors.initials: J
authors.lastname: Calovski
authors.forename: Emilija
authors.initials: E
authors.lastname: Sandevska
authors.forename: Baskim
authors.initials: B
authors.lastname: Osmani
authors.forename: Tatjana
authors.initials: T
authors.lastname: Sotirova
authors.forename: Svetlana
authors.initials: S
authors.lastname: Balkanov
authors.forename: Dusko
authors.initials: D
authors.lastname: Dukovski
authors.forename: Arif
authors.initials: A
authors.lastname: Ljatifi
authors.forename: Goce
authors.initials: G
authors.lastname: Spasovski
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000150:complications / Q000201:enzymology* / Q000473:pathology; D018826:CD13 Antigens / Q000097:blood; D003404:Creatinine / Q000097:blood / Q000652:urine; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D007674:Kidney Diseases / Q000097:blood / Q000175:diagnosis* / Q000201:enzymology; D007687:Kidney Tubules, Proximal / Q000201:enzymology* / Q000648:ultrastructure; D008297:Male; D008871:Microvilli / Q000201:enzymology; D008875:Middle Aged; D011237:Predictive Value of Tests; D012217:Rheumatoid Factor / Q000097:blood; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D014508:Urea / Q000097:blood; D001613:beta 2-Microglobulin / Q000652:urine; D005723:gamma-Glutamyltransferase / Q000097:blood
chemical_list: D001613:beta 2-Microglobulin; D014508:Urea; D012217:Rheumatoid Factor; D003404:Creatinine; D005723:gamma-Glutamyltransferase; D018826:CD13 Antigens