Intracellular cytokines in blood T cells in lung transplant patients--a more relevant indicator of immunosuppression than drug levels.
Allograft rejection remains a major cause of morbidity and mortality following lung transplantation and is associated with an increase in T-cell pro-inflammatory cytokine expression. Systemic levels of immunosuppressive drugs used to reduce pro-inflammatory cytokine expression are closely monitored to their 'therapeutic range'. However, it is currently unknown if levels of these drugs correlate with pro-inflammatory cytokine expression in peripheral blood T cells. To investigate the immunomodulatory effects of currently used immunosuppressive regimes on peripheral blood T-cell cytokine production, whole blood from stable lung transplant patients and control volunteers were stimulated in vitro and cytokine production by CD8+ and CD4+ T-cell subsets determined using multiparameter flow cytometry. T-cell IL-2 and TNFalpha production was significantly reduced from lung transplant patients compared to controls. CD4+ T-cell production of IFNgamma was also significantly reduced from lung transplant patients but production of IFNgamma by CD8+ T cells remained unchanged. There was an excellent correlation between the percentage of CD8+ T cells and the percentage of CD8+ T cells producing IFNgamma from transplant patients. T-cell IL-4 and CD8+ T-cell production of TGFbeta was significantly increased from lung transplant patients. We now provide evidence that current immunosuppression protocols have limited effect on peripheral blood IFNgamma production by CD8+ T-cells but do up-regulate T-cell anti-inflammatory cytokines. Drugs that effectively reduce IFNgamma production by CD8+ T cells may improve current protocols for reducing graft rejection in these patients. Intracellular cytokine analysis using flow cytometry may be a more appropriate indicator of immunosuppression than drug levels in these patients. This technique may prove useful in optimizing therapy for individual patients.
Hodge
G
G
Department of Thoracic Medicine, Royal Adelaide Hospital, Adelaide, South Australia. hodgeg@mail.wch.sa.gov.au
Hodge
S
S
Reynolds
P
P
Holmes
M
M
D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D016207:Cytokines / Q000032:analysis*; D005434:Flow Cytometry / Q000379:methods; D006801:Humans; D007165:Immunosuppression Therapy / Q000379:methods*; D007371:Interferon-gamma / Q000032:analysis; D007376:Interleukin-2 / Q000032:analysis; D016040:Lung Transplantation / Q000276:immunology*; D018655:Lymphocyte Count / Q000379:methods; D013601:T-Lymphocytes / Q000276:immunology*; D016212:Transforming Growth Factor beta / Q000032:analysis; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis
D016207:Cytokines; D007376:Interleukin-2; D016212:Transforming Growth Factor beta; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma