title: Quantitation of immunosuppression by flow cytometric measurement of the capacity of T cells for interleukin-2 production.
abstract: BACKGROUND
  Methods to quantitate the effects of immunosuppressive drugs on immune reactivity might be helpful for monitoring immunosuppressive treatment. Cyclosporine (CsA) inhibits the induction of cytokine synthesis in T cells, and measurement of interleukin (IL)-2 production might constitute a parameter of this drug's effect.
  
  
  METHODS
  We determined the percentages of CD4+ and CD8+ lymphocytes producing IL-2 upon stimulation by phorbol myristate acetate and calcium ionophore in whole blood culture, using immunostaining of intracytoplasmatic and membrane markers, followed by multiparameter flow cytometry. A total of 38 clinically stable transplant patients on various immunosuppressive protocols were studied.
  
  
  RESULTS
  The percentage of CD4+ T cells producing IL-2 was strongly reduced in patients compared with healthy controls (23% [range, 3-68%] vs. 59.0% [range, 41-70%]; P=0.000035). The percentage of CD4+ T cells producing IL-2 was negatively correlated with the CsA level (Rc=-0.0821, P=0.00002297) but not with prednisolone or azathioprine doses. Fewer CD8+ T cells produced IL-2 in transplant patients compared with controls, but the difference failed to reach statistical significance. The percentage of CD8+ T cells capable of producing IL-2 was inversely correlated to CsA levels (Rc=-0.0375, P=0.0011).
  
  
  CONCLUSIONS
  These data suggest that the functional effects of CsA in transplant recipients can be quantitatively determined and that the capacity of CD4+ T cells to produce IL-2 upon stimulation constitutes a functional parameter of CsA effects on the immune system. Prospective studies are required to determine whether this method is useful for clinical monitoring.
authors.affiliation: Department of Gastroenterology and Hepatology, University Hospital, Groningen, The Netherlands.
authors.forename: A P
authors.initials: AP
authors.lastname: van den Berg
authors.forename: W N
authors.initials: WN
authors.lastname: Twilhaar
authors.forename: G
authors.initials: G
authors.lastname: Mesander
authors.forename: W J
authors.initials: WJ
authors.lastname: van Son
authors.forename: W
authors.initials: W
authors.lastname: van der Bij
authors.forename: I J
authors.initials: IJ
authors.lastname: Klompmaker
authors.forename: M J
authors.initials: MJ
authors.lastname: Slooff
authors.forename: T H
authors.initials: TH
authors.lastname: The
authors.forename: L H
authors.initials: LH
authors.lastname: de Leij
mesh_terms: D000328:Adult; D000368:Aged; D001379:Azathioprine / Q000627:therapeutic use; D001803:Blood Transfusion; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D002478:Cells, Cultured; D016572:Cyclosporine / Q000493:pharmacokinetics / Q000627:therapeutic use; D004359:Drug Therapy, Combination; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D006650:Histocompatibility Testing; D006801:Humans; D007165:Immunosuppression Therapy; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D007376:Interleukin-2 / Q000096:biosynthesis*; D016030:Kidney Transplantation / Q000276:immunology*; D016031:Liver Transplantation / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D015166:Monitoring, Immunologic / Q000379:methods*; D010298:Parity; D011239:Prednisolone / Q000627:therapeutic use; D012016:Reference Values; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D007166:Immunosuppressive Agents; D007376:Interleukin-2; D016572:Cyclosporine; D011239:Prednisolone; D001379:Azathioprine