title: CD26/dipeptidyl peptidase IV: a comparative study of healthy persons and kidney transplant recipients before and early after transplantation.
abstract: OBJECTIVE
  Human CD26 is co-stimulatory for lymphocytes, circulates in a soluble form in blood (sCD26), and has intrinsic dipeptidyl peptidase IV (DPPIV) activity. Associations between CD26 expression on the surface of T cells (CD26+/CD3+) and acute rejection and between (CD26+/CD3+)/DPPIV and clinical immunosuppression have been reported. These results encouraged the investigation of CD26 as a potential biomarker to optimize immunosuppressive therapy. To better understand the significance of CD26, a comparative study of CD26 expression on CD3+ cells, sCD26 concentration, and DPPIV activity in healthy persons (HP) and kidney transplant recipients (KTR) was performed.
  
  
  METHODS
  Thirty-one HP and 34 KTR were included in the study. CD26+/CD3+ was determined by FACS, sCD26 concentration was determined by ELISA, and DPP activity was determined by spectrophotometry. For KTR, these parameters were studied on the day before transplantation (preTx) and 7±1days after transplantation (postTx).
  
  
  RESULTS
  There was no significant difference in the CD26+/CD3+, sCD26, and DPPIV data regarding gender, donor type (16 living donors), delayed graft function (n=8), or presence of ≥4HLA mismatches (n=16). Compared to the HP data, preTx CD26+/CD3+ was 4.5-fold higher, sCD26 was 1.2-fold higher, and DPPIV showed no significant difference. PostTx, CD26+/CD3+ was 3.8-fold higher, and sCD26 and DPPIV decreased significantly, reaching lower values than that observed in HP. Re-transplanted patients (n=5) showed significantly lower preTx CD26+/CD3+ expression than patients receiving their first transplant. Patients with preemptive transplantation (n=7) showed higher postTx CD26+/CD3+ expression than patients on dialysis.
  
  
  CONCLUSIONS
  CD26 expression on CD3+ cells was strongly increased in patients with end stage kidney disease compared to HP and remained high early postTx. The differences in sCD26 and DPPIV behavior compared to that of CD26+/CD3+ postTx may reflect a regulatory response to the new immunological situation and the effects of therapy.
authors.affiliation: Zentralinstitut für Transfusionsmedizin, Klinikum-Stuttgart, Kriegsbergstrasse 60, D-70174 Stuttgart, Germany. Electronic address: s.leicht@klinikum-stuttgart.de.
authors.forename: Simone
authors.initials: S
authors.lastname: Leicht
authors.forename: Maria
authors.initials: M
authors.lastname: Shipkova
authors.forename: Corinne
authors.initials: C
authors.lastname: Klett
authors.forename: Helena
authors.initials: H
authors.lastname: Gert
authors.forename: Eva
authors.initials: E
authors.lastname: Altrock
authors.forename: Jens
authors.initials: J
authors.lastname: Wilhelm
authors.forename: Renate
authors.initials: R
authors.lastname: Bolley
authors.forename: Jochen
authors.initials: J
authors.lastname: Wollmeyer
authors.forename: Andrea
authors.initials: A
authors.lastname: Ender
authors.forename: Beate
authors.initials: B
authors.lastname: Luz
authors.forename: Christoph
authors.initials: C
authors.lastname: Olbricht
authors.forename: Eberhard
authors.initials: E
authors.lastname: Wieland
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D017252:CD3 Complex / Q000097:blood / Q000235:genetics; D016022:Case-Control Studies; D018819:Dipeptidyl Peptidase 4 / Q000097:blood* / Q000235:genetics / Q000378:metabolism; D057075:Enzyme Assays; D005260:Female; D015870:Gene Expression; D006801:Humans; D007676:Kidney Failure, Chronic / Q000201:enzymology* / Q000473:pathology / Q000601:surgery; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D013601:T-Lymphocytes / Q000201:enzymology* / Q000473:pathology; D055815:Young Adult
chemical_list: D015415:Biomarkers; D017252:CD3 Complex; C042807:DPP4 protein, human; D018819:Dipeptidyl Peptidase 4
keywords: Biomarkers; CD26; Dipeptidyl peptidase IV activity; Kidney transplantation; T cell activation; sCD26