Higher serum DPP-4 enzyme activity and decreased lymphocyte CD26 expression in type 1 diabetes

Pathol Oncol Res. 2011 Dec;17(4):925-30. doi: 10.1007/s12253-011-9404-9. Epub 2011 Jul 22.


Dipeptidyl peptidase-4 (DPP-4) is involved in the metabolism of peptide hormones, T-cell activation and proliferation. In type 1 diabetes mellitus (T1DM) β-cell destruction involves a number of dysregulated T-cells. Our aim was to assess the serum DPP-4 activity and the lymphocyte membrane bound CD26 expression in patients with type 1 diabetes and healthy controls. Ninety-eight (T1DM: 48, F/M = 20/28, mean age: 34.4y; control: 50, F/M = 39/11 mean age: 32,4y) individuals were included. Fasting serum DPP-4 enzymatic activity, plasma glucose (FPG), CD26 expression on CD3+, CD4+ and CD8+ lymphocytes, HbA1c and body mass index (BMI) were assessed. ICA and GAD antibodies were assessed in the T1DM group. DPP-4 enzymatic activity was determined by kinetic enzyme assay, ICA and GAD were assessed by ELISA. Determination of the CD26 expression on CD3+, CD4+ and CD8+ lymphocytes was performed by flow-cytometric analysis. We found higher serum DPP-4 activity (Mean: T1DM: 30.069 U/L, control: 22.62 U/L, p < 0.0001) and decreased CD26 lymphocyte expression on all lymphocyte subpopulations in T1DM. Fasting serum DPP-4 activity was independent from the ICA or GAD status of patients with T1DM. Here we first present that the serum DPP-4 activity is increased and the lymphocyte membrane bound CD26 expression is decreased in type 1 diabetes. Decreased lymphocyte membrane bound CD26 expression in T1DM might be a novel part of the T-lymphocyte regulatory dysfunction observed in type 1 diabetes mellitus. These results might provide some basis for the clinical implication of DPP-4 inhibition in patients with T1DM.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Autoantibodies / immunology
  • Blood Glucose / metabolism
  • Body Mass Index
  • Case-Control Studies
  • Diabetes Mellitus, Type 1 / blood
  • Diabetes Mellitus, Type 1 / enzymology*
  • Diabetes Mellitus, Type 1 / immunology*
  • Diabetes Mellitus, Type 2 / blood
  • Diabetes Mellitus, Type 2 / enzymology
  • Diabetes Mellitus, Type 2 / immunology
  • Dipeptidyl Peptidase 4 / biosynthesis*
  • Dipeptidyl Peptidase 4 / blood*
  • Dipeptidyl Peptidase 4 / immunology
  • Dipeptidyl Peptidase 4 / metabolism
  • Fasting / blood
  • Female
  • Glutamate Decarboxylase / immunology
  • Glycated Hemoglobin / metabolism
  • Humans
  • Insulin-Secreting Cells / enzymology
  • Insulin-Secreting Cells / immunology
  • Lymphocyte Activation / immunology
  • Male
  • Middle Aged
  • T-Lymphocytes / enzymology
  • T-Lymphocytes / immunology*


  • Autoantibodies
  • Blood Glucose
  • Glycated Hemoglobin A
  • hemoglobin A1c protein, human
  • islet cell antibody
  • Dipeptidyl Peptidase 4
  • Glutamate Decarboxylase