Objective: There is evidence that in patients with chronic hepatitis C, immunotherapy with interferon-alpha (IFN alpha) may induce depression. A lowered activity of peptidases, such as prolylendopeptidase (PEP) and dipeptidyl peptidase IV (DPP IV), occurs in depression. This study examines whether lowered serum PEP or DPP IV activity before starting IFN alpha-based immunotherapy predicts the increase in depressive symptoms during immunotherapy.
Method: Serum PEP and DPP IV activities are measured in patients with hepatitis C before and 2, 4 and 16 weeks after starting IFN alpha-based immunotherapy. The Montgomery Asberg Depression Rating Scale (MADRS) and the Hamilton Anxiety Rating Scale (HAM-A) are completed.
Results: Patients with lower baseline PEP or DPP IV had significantly higher MADRS and HAM-A scores both at baseline and during immunotherapy. Patients with lower baseline DPP IV had significantly higher increases in the MADRS following IFN alpha treatment.
Conclusion: Lower baseline PEP and DPP IV predict higher depressive and anxiety ratings during IFN alpha-based immunotherapy.