Proline-specific peptidase activities (DPP4, PRCP, FAP and PREP) in plasma of hospitalized COVID-19 patients

An Bracke, Emilie De Hert, Michelle De Bruyn, Karen Claesen, Gwendolyn Vliegen, Alexandra Vujkovic, Lida van Petersen, Fien H R De Winter, An Hotterbeekx, Isabel Brosius, Caroline Theunissen, Sabrina Van Ierssel, Maartje van Frankenhuijsen, Erika Vlieghe, Koen Vercauteren, Pieter Van der Veken, Dirk Hendriks, Samir Kumar-Singh, Ingrid De Meester

Research output: Contribution to journalA1: Web of Science-articlepeer-review


BACKGROUND: COVID-19 patients experience several features of dysregulated immune system observed in sepsis. We previously showed a dysregulation of several proline-selective peptidases such as dipeptidyl peptidase 4 (DPP4), fibroblast activation protein alpha (FAP), prolyl oligopeptidase (PREP) and prolylcarboxypeptidase (PRCP) in sepsis. In this study, we investigated whether these peptidases are similarly dysregulated in hospitalized COVID-19 patients.

METHODS: Fifty-six hospitalized COVID-19 patients and 32 healthy controls were included. Enzymatic activities of DPP4, FAP, PREP and PRCP were measured in samples collected shortly after hospital admission and in longitudinal follow-up samples.

RESULTS: Compared to healthy controls, both DPP4 and FAP activities were significantly lower in COVID-19 patients at hospital admission and FAP activity further decreased significantly in the first week of hospitalization. While PRCP activity remained unchanged, PREP activity was significantly increased in COVID-19 patients at hospitalization and further increased during hospital stay and stayed elevated until the day of discharge.

CONCLUSION: The changes in activities of proline-selective peptidases in plasma are very similar in COVID-19 and septic shock patients. The pronounced decrease in FAP activity deserves further investigation, both from a pathophysiological viewpoint and as its utility as a part of a biomarker panel.

Original languageEnglish
JournalClinica Chimica Acta
Pages (from-to)4-11
Number of pages8
Publication statusPublished - 2022


  • COVID-19
  • Carboxypeptidases
  • Dipeptidyl Peptidase 4
  • Endopeptidases
  • Gelatinases
  • Humans
  • Membrane Proteins
  • Peptide Hydrolases
  • Proline
  • Serine Endopeptidases
  • Shock, Septic


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