Dipeptidyl peptidase IV and adenosine deaminase activity - Decrease in depression

Dipeptidyl peptidase IV (DPPIV) and adenosine deaminase (ADA), two T cell a ssociated enzymes, are known to have a possible interaction and play essent ial roles in immune system functioning. On the other hand, depression has b een shown to be accompanied with some immune-inflammatory alterations. In t his regard, in order to make a contribution to the understanding of the ong oing immune disturbances in depression, serum DPPIV and ADA activities were determined in minor and major depressives and compared with healthy contro ls. Both enzyme activities were found to be decreased in major depressives compared to controls while only DPPIV activity was significantly lower in m ajor depressives than the minor depressives. There were significant inverse relationships between enzyme activities and the severity of depression. Mo reover, a positive intracorrelation was found between decreased DPPIV and A DA levels. The correlated decrease in DPPIV and ADA, might be a further sup port for their possible association. Results also suggest that decreased en zyme activities might reflect the impaired immune state in depression while major depressed patients might have a greater tendency to immune dysfuncti on than the minor depressed ones. (C) 1999 Elsevier Science Ltd. All rights reserved.