title: Serum dipeptidyl peptidase IV (DPP IV, CD26) activity in chronic hepatitis C.
abstract: BACKGROUND
  DPP IV is a cell surface ectoenzyme widely distributed in the human body. It has been implicated in T-cell activation, hepatocyte-extracellular-matrix interactions and fibroblast proliferation. Furthermore, upregulated CD26 expression has been found on the surface of human hepatoma cells transfected with hepatitis C virus (HCV) c-DNA. We examined the serum DPP IV activity in a large number of patients with chronic HCV infection in a cross-sectional study. We also investigated whether the activity differs from that in controls and depends upon the response to interferon (IFN) therapy.
  
  
  METHODS
  Serum DPP IV activity was measured by microplate-based (Multiskan-Plus-MKII, Labsystem) kinetic assay in 144 patients with chronic HCV infection. Seventy-four out of 144 patients (46 non-responders, 28 responders) were formerly treated with interferon. Sixty healthy blood donors served as controls. Gly-Pro-PNA (Bachem, Torrance, USA) was used as substrate. Results are expressed in nmol/ml/min (U/l). Shapiro-Wilk's test, Mann-Whitney U test and Spearman rank order correlation were used for statistical analysis.
  
  
  RESULTS
  Serum DPP IV activity was significantly higher (mean = 20.89 [s 9.6]) in patients with chronic HCV infection than in healthy controls (12.39 [2.76, P < 10(-5)]). The enzyme activities significantly differed in naive HCV-positive patients (22.2 [9.89, P < 10(-5)]) and non-responders (23.28 [9.57, P < 10(-5)]) from that in the healthy controls and also from that in responders (13.69 [4.21]). Correlation was found between DPP IV activity and AST (r = 0.44, P < 10(-5)), ALT (r = 0.44, P < 10(-5)), GGT (r = 0.41, P < 10(-5)) levels.
  
  
  CONCLUSIONS
  Serum DPP IV activity seems to be an indicator of HCV induced liver injury. The activity may reflect the efficacy of interferon therapy.
authors.affiliation: First Dept. of Internal Medicine, Semmelweis University, Budapest, Hungary. FIRNEISZ@bel1.sote.hu
authors.forename: G
authors.initials: G
authors.lastname: Firneisz
authors.forename: P L
authors.initials: PL
authors.lastname: Lakatos
authors.forename: F
authors.initials: F
authors.lastname: Szalay
mesh_terms: D000328:Adult; D000368:Aged; D000998:Antiviral Agents / Q000627:therapeutic use; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D018819:Dipeptidyl Peptidase 4 / Q000097:blood*; D005260:Female; D019698:Hepatitis C, Chronic / Q000188:drug therapy / Q000201:enzymology*; D006801:Humans; D007372:Interferons / Q000627:therapeutic use; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome
chemical_list: D000998:Antiviral Agents; D015415:Biomarkers; D007372:Interferons; D018819:Dipeptidyl Peptidase 4