Is there an impact of treatment with DPP-4 inhibitors on lymphocyte subpopulations in type 2 diabetic patients?

Introduction: Dipeptidil peptidase 4 inhibitors (DPP-4) are a group of antihyperglycemic agents. DPP-4 is an enzyme expressed on lymphocyte surface as co-stimulatory molecule in activation processes. The aim was to assess lymphocyte subpopulations initially and after 14 days of treatment with DPP-4 inhibitors sitagliptin, saxagliptin and vildagliptin. Material and methods: The study was conducted in three groups 10 subjects each, of type 2 diabetic patients. In subjects studied an initial tests followed by repeated ones after 14 days of treatment with sitagliptin, saxagliptin, and vildagliptin in therapeutic doses were performed. Baseline test as well as lymphocyte subpopulations (total T cells, and T-cell subsets CD4+, CD8+, CD26+, CD45RA+, CD45RO+, CD4+/CD25+) using 7-colour flow cytometry method were performed. Results: In patients receiving sitagliptin no significant increase in lymphocyte subpopulations were observed. In patients who received vildagliptin significant increase of total T-cells (p < 0.05); in patients treated with saxagliptin significant (p < 0.05) though mild increased percentage of total T-cells and CD4+, CD26+, CD45RO+ subsets were found. Conclusions: The study showed mild but significant increase of several T-cell subsets after treatment with saxagliptin and vildagliptin with non significant elevation after treatment with sitagliptin. It seems that changes are not expressed enough to have a clinical impact.