A role for cytokine measurement in therapeutic monitoring of immunosuppressive drugs following lung transplantation

Cytokines in Lung Transplantation

Lung transplantation has developed significantly in recent years, but post-transplant care and patients' survival still need to be improved. Moreover, organ shortage urges novel modalities to improve the quality of unsuitable lungs. Cytokines, the chemical mediators of the immune system, might be used for diagnostic and therapeutic purposes in lung transplantation. Cytokine monitoring pre- and post-transplant could be applied to the prevention and early diagnosis of injurious inflammatory events including primary graft dysfunction, acute cellular rejection, bronchiolitis obliterans syndrome, restrictive allograft syndrome, and infections. In addition, preoperative cytokine removal, specific inhibition of proinflammatory cytokines, and enhancement of anti-inflammatory cytokines gene expression could be considered therapeutic options to improve lung allograft survival. Therefore, it is essential to describe the cytokines alteration during inflammatory events to gain a better insight into their role in developing the abovementioned complications. Herein, cytokine fluctuations in lung tissue, bronchoalveolar fluid, peripheral blood, and exhaled breath condensate in different phases of lung transplantation have been reviewed; besides, cytokine gene polymorphisms with clinical significance have been summarized.

Bronchiolitis obliterans syndrome is associated with increased senescent lymphocytes in the small airways

BACKGROUND

Immunosuppression therapy is ineffective at preventing bronchiolitis obliterans syndrome (BOS), primarily a disease of the small airways (SAs). Our previous reports show increased senescent CD28null T and natural killer T (NKT)-like cells in the peripheral blood of patients with BOS and increased cytotoxic, proinflammatory lymphocytes in the SAs. We hypothesized that the cytotoxic, proinflammatory lymphocytes in the SAs would be steroid-resistant senescent CD28null lymphocytes.

METHODS

Intracellular cytotoxic mediator granzyme B, interferon (IFN)-γ and tumor necrosis factor (TNF)-α proinflammatory cytokines, and CD28 were measured in the blood, bronchoalveolar lavage, large airway, and SA brushing T and NKT-like cells from 10 patients with BOS, 11 stable lung transplant recipients, and 10 healthy age-matched controls. SA brushings were cultured in the presence of ±1 µmol/liter prednisolone, ±5 mg/liter theophylline, and ±2.5 ng/ml cyclosporine A, and IFN-γ and TNF-α proinflammatory cytokines were assessed using flow cytometry.

RESULTS

Increased SA CD28null T and NKT-like cells were identified in patients with BOS compared with that in the controls and stable transplant recipients. Loss of CD28 was associated with increased T and NKT-like cells expressing granzyme B, IFN-γ, and TNF-α. Loss of CD28 expression by CD8+ T cells was significantly associated with forced expiratory volume in 1 sec (R = 0.655, p = 0.006) and with time after transplantation (R = -0.552, p = 0.041). Treatment with prednisolone + theophylline + cyclosporin A inhibited IFN-γ and TNF-α production by SA CD28null CD8+ T and NKT-like cells additively.

CONCLUSIONS

BOS is associated with the loss of CD28 in SA cytotoxic, proinflammatory senescent T and NKT-like lymphocytes. Treatment options that target the proinflammatory nature of these cells in the SAs may improve graft survival.

Analysis of effectiveness of Iranian snake antivenom on Viper venom induced effects including analysis of immunologic biomarkers in the Echis carinatus sochureki envenomed victims

Snakebite is an important toxicologic emergency with the potential of triggering local and systemic inflammation. Antivenom has remained the mainstay of treatment for snakebite envenomation. In this study we sought to investigate the effectiveness of Iranian antivenom in a series of 44 viper envenomed patients through analysis of changes in clinical severity and the levels of inflammatory markers. Clinical envenomation severity assessed by snakebite severity score (SSS) and laboratory exams of the patients were recorded before (baseline visit) and after antivenom therapy. During 12-h antivenom therapy, the median (range) score of SSS significantly decreased from 3.5 (2-10) on admission to 1 (0-5) in the last visit (P < 0.001). Moreover, a significant decrease in prothrombin time and international normalized ratio was found (P = 0.006 and 0.008; respectively). Plasma concentrations of interleukin (IL) 1-β, IL-6, IL-8, tumor necrosis factor α (TNF-α), complement hemolytic activity (CH50) were also measured in 10 severely Echis carinatus sochureki envenomed victims and 10 age and gender-matched healthy controls. Except IL-8, the baseline levels of IL-1β, IL-6 and TNF-α in victims were significantly higher than healthy controls (P = 0.005, <0.001 and < 0.001, respectively). Moreover, the baseline level of CH50 was significantly lower in the patients compared to healthy controls (P < 0.001). After 12-h antivenom therapy, the plasma levels of IL-1β, IL-6 and TNF-α significantly decreased (P = 0.032, 0.006 and 0.003, respectively), the levels of IL-8 remained relatively unchanged and the CH50 significantly increased (P = 0.011). Iranian snake antivenom was effective in treating viper bite envenomation as it reversed clinical venom effects and restored near normal underlying inflammatory status. This study is the first to ascertain and report the effectiveness of this antivenom in human subjects.

BOS is associated with decreased HDAC2 from steroid resistant lymphocytes in the small airways

Immunosuppression therapies including corticosteroids fail to prevent bronchiolitis obliterans syndrome (BOS), primarily a disease of the small airways, following lung transplantation. We reported increases in steroid-resistant proinflammatory lymphocytes and their loss of histone deacetylase 2 (HDAC2), an important mediator of steroid action, in the blood of stable lung transplant recipients. We noted similar increases in the steroid-resistant lymphocytes in both the blood and small airways in BOS compared with the large airways. We hypothesized that these small airway cells would also exhibit a loss of HDAC2, and that these changes could be reversed by treatment with theophylline (HDAC2 activator). Blood, bronchoalveolar lavage and large and small airway brushings were collected from lung transplant patients with BOS (n = 12) or stable lung function (n = 18) and healthy aged-matched controls (n = 13). Intracellular proinflammatory cytokines [interferon (IFN-γ) and tumour necrosis factor (TNF)-α and HDAC2 were measured in CD8⁺ T, natural killer (NK) T-like and NK cells from cultured small airway brushings ± 5 mg/l theophylline ± 1 µM prednisolone using flow cytometry. Increased small airway CD8 T, NK T-like and NK cells were identified in BOS versus stable transplant and controls. In BOS, these cells exhibited increased IFN-γ/TNF-α and a loss of HDAC2. HDAC2 expression by small airway CD8⁺ T cells correlated with forced expiratory volume in 1 s (FEV₁ ) (R = 0·880, P = 0·031). Theophylline and prednisolone synergistically up-regulated HDAC2 in CD8⁺ T cells. BOS is associated with loss of HDAC2 from steroid-resistant proinflammatory CD8⁺ T, NK T-like and NK cells in the small airways. Therapeutically increasing HDAC2 in these lymphocytes may reduce steroid resistance and improve graft survival.

Bronchiolitis obliterans syndrome is associated with increased p-glycoprotein expression and loss of glucocorticoid receptor from steroid-resistant proinflammatory CD8+ T cells

Immunosuppressive therapy fails to suppress the production of proinflammatory cytokines, particularly by CD8+ T cells, in stable lung transplant recipients and those undergoing chronic rejection, suggesting that some patients may become relatively resistant to immunosuppressants such as glucocorticoids (GC). We have shown loss of GC receptor (GCR) from the CD8+ cells, and we hypothesized that the drug membrane efflux pump, p-glycoprotein-1 (Pgp), may also be involved in lymphocyte steroid resistance following lung transplant. Pgp/GCR expression and interferon (IFN)-γ/tumour necrosis factor (TNF)-α proinflammatory cytokine production was measured in blood lymphocytes from 15 stable lung transplant patients, 10 patients with bronchiolitis obliterans syndrome (BOS) and 10 healthy aged-matched controls (± prednisolone ± Pgp inhibitor, cyclosporin A ± GCR activator, Compound A) using flow cytometry. Both Pgp+ and Pgp- lymphocyte subsets from all subjects produced IFN-γ/TNF-α proinflammatory cytokines. Pgp expression was increased in CD8+ Pgp+ T cells and correlated with IFN-γ/TNF-α expression and BOS grade. Reduced GCR was observed in CD8+ Pgp- T, natural killer (NK) T-like and NK cells from stable patients compared with controls, and reduced further in CD8+ Pgp- T cells in BOS. The addition of 2·5 ng/ml cyclosporin A and 1 µM prednisolone inhibit IFN-γ/TNF-α production significantly by CD8+ Pgp+ T cells from BOS patients. The addition of 10 µM Compound A and 1 µM prednisolone inhibit IFN-γ/TNF-α production significantly by CD8+ Pgp- T cells from BOS patients. BOS is associated with increased Pgp expression and loss of GCR from steroid-resistant proinflammatory CD8+ T cells. Treatments that inhibit Pgp and up-regulate GCR in CD8+ T cells may improve graft survival.

Immunomodulatory plasticity of mesenchymal stem cells: a potential key to successful solid organ transplantation

Organ transplantation remains to be a treatment of choice for patients suffering from irreversible organ failure. Immunosuppressive (IS) drugs employed to maintain the allograft have shown excellent short-term graft survival, but, their long-term use could contribute to immunological and non-immunological risk factors, resulting in graft dysfunctionalities. Upcoming IS regimes have highlighted the use of cell-based therapies, which can eliminate the risk of drug-borne toxicities while maintaining efficacy of the treatment. Mesenchymal stem cells (MSCs) have been considered as an invaluable cell type, owing to their unique immunomodulatory properties, which makes them desirable for application in transplant settings, where hyper-activation of the immune system is evident. The immunoregulatory potential of MSCs holds true for preclinical studies while achieving it in clinical studies continues to be a challenge. Understanding the biological factors responsible for subdued responses of MSCs in vivo would allow uninhibited use of this therapy for countless conditions. In this review, we summarize the variations in the preclinical and clinical studies utilizing MSCs, discuss the factors which might be responsible for variability in outcome and propose the advancements likely to occur in future for using this as a "boutique/personalised therapy" for patient care.

BOS Is Associated With Increased Cytotoxic Proinflammatory CD8 T, NKT-Like, and NK Cells in the Small Airways

BACKGROUND

Immunosuppression therapy after lung transplantation fails to prevent bronchiolitis obliterans syndrome (BOS) in many patients, primarily a disease of the small airways. We have reported that BOS is associated with a lack of suppression of cytotoxic mediators, and proinflammatory cytokines, in peripheral blood T, NKT-like (particularly CD8+) and NK cells. We also showed a loss of glucocorticoid receptor (GCR) in proinflammatory lymphocytes after transplant. It is unknown whether these proinflammatory lymphocytes target the small and/or large airways in BOS.

METHODS

Blood, bronchoalveolar lavage, large proximal, and small distal airway brushings were collected from patients with BOS (n = 10), stable lung transplant patients (n = 18), and healthy aged-matched controls (n = 10). Intracellular cytotoxic mediators (perforin/granzyme B), proinflammatory cytokines (IFNγ/TNFα), and expression of GCR were determined in lymphocytes subsets from cultured blood using flow cytometry.

RESULTS

Increases in CD8 T cells, NKT-like cells, and NK cells were found in the small distal airways in BOS compared with stable patients and controls. An increase in perforin, granzyme B, IFNγ, TNFα, and a loss of GCR from these lymphocyte subsets was also found in BOS. GCR expression by CD8+ T cells from small airways correlated with FEV1 (R = 0.834, P = 0.039). Many of these changes significantly differed from those in the large airways.

CONCLUSIONS

BOS is associated with increased cytotoxic/proinflammatory CD8+ T, NKT-like, and NK cells in the small airways. Treatments that increase GCR in these lymphocyte subsets may improve graft survival.

Histone deacetylase 2 is decreased in peripheral blood pro-inflammatory CD8+ T and NKT-like lymphocytes following lung transplant

BACKGROUND AND OBJECTIVE

Immunosuppression therapy following lung transplantation fails to prevent chronic rejection in many patients, which is associated with lack of suppression of cytotoxic mediators and pro-inflammatory cytokines in peripheral blood T and natural killer T (NKT)-like cells. Histone acetyltransferases (HATs) and histone deacetylases (HDACs) upregulate/downregulate pro-inflammatory gene expression, respectively; however, differences in the activity of these enzymes following lung transplant are unknown. We hypothesized decreased HDAC2 expression and increased HAT expression in pro-inflammatory lymphocytes following lung transplant.

METHODS

Blood was collected from 18 stable lung transplant patients and 10 healthy age-matched controls. Intracellular pro-inflammatory cytokines and HAT/HDAC2 expression were determined in lymphocyte subsets following culture using flow cytometry.

RESULTS

A loss of HDAC2 in cluster of differentiation (CD) 8+ T and NKT-like cells in transplant patients compared with controls was noted (CD8+ T: 28 ± 10 (45 ± 10), CD8+NKT-like: 30 ± 13 (54 ± 16) (mean ± SD transplant) (control)). Loss of HDAC2 was associated with an increased percentage of CD8+ T and NKT-like cells expressing perforin, granzyme b, interferon gamma (IFN-γ) and TNF-α (no change in HAT expression in any lymphocyte subset). There was a negative correlation between loss of HDAC2 expression by CD8+ T cells with cumulative dose of prednisolone and time post-transplant. Treatment with 10 mg/L theophylline + 1 µmol/L prednisolone or 2.5 ng/mL cyclosporine A synergistically upregulated HDAC2 and inhibited IFN-γ and TNF-α production by CD8+ T and NKT-like lymphocytes.

CONCLUSION

HDAC2 is decreased in CD8+ T and NKT-like pro-inflammatory lymphocytes following lung transplant. Treatment options that increase HDAC2 may improve graft survival.

Cyclosporine use in hematopoietic stem cell transplantation: pharmacokinetic approach

Cyclosporine is one of the most vital agents in the process of successful allogeneic hematopoietic stem cell transplantation. Despite a long history and worldwide extent of cyclosporine use for prevention of graft versus host disease, currently there are lots of uncertainties about its optimal method of application to reach the best clinical outcome. A major portion of this problem stems from complicated cyclosporine pharmacokinetics. Study of cyclosporine pharmacokinetic behavior can significantly help recognition of its effectiveness and consequently, optimization of dosing, administration, monitoring and management of adverse effects. In this review, highly accredited but sparse scientific data are gathered in order to provide a better insight for preparation of practice guidelines and directing future studies for allogeneic hematopoietic cell recipients.

Cytokine signatures of human whole blood for monitoring immunosuppression

How to evaluate status of the immune system is extremely critical for clinical immunosuppressive treatment. In this study, we tested the secretion of cytokines in undiluted whole blood samples stimulated with Phorbol 12-myristate 13-acetate (PMA) and ionomycin (IONO), and compared the effects of dexamethasone (DEX), cyclosporine A (CsA) or mycophenolic acid (MPA), either alone or in combination, on cytokine profiles. The results showed that both DEX and CsA dose-dependently inhibited the production of eleven cytokines: interleukin (IL)-2, IL-4, IL-5, IL-6, IL-13, IL-17, interferon γ (IFN-γ), tumor necrosis factor α (TNF-α), granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF). Unexpectedly, MPA showed no obvious influences except for the mild inhibition on GM-CSF production. In combination treatment, cytokine profiles reflect not only the synergistic effects among drugs, but also the specific effect of the individual drug. Thus, the effects of different immunosuppressants could be reflected through their specific cytokine signatures, which can be applied to maximize immunosuppressive effects, while to minimize risk of infections and help physicians to reasonably apply immunosuppressants.

Real-time, aptamer-based tracking of circulating therapeutic agents in living animals

A sensor capable of continuously measuring specific molecules in the bloodstream in vivo would give clinicians a valuable window into patients' health and their response to therapeutics. Such technology would enable truly personalized medicine, wherein therapeutic agents could be tailored with optimal doses for each patient to maximize efficacy and minimize side effects. Unfortunately, continuous, real-time measurement is currently only possible for a handful of targets, such as glucose, lactose, and oxygen, and the few existing platforms for continuous measurement are not generalizable for the monitoring of other analytes, such as small-molecule therapeutics. In response, we have developed a real-time biosensor capable of continuously tracking a wide range of circulating drugs in living subjects. Our microfluidic electrochemical detector for in vivo continuous monitoring (MEDIC) requires no exogenous reagents, operates at room temperature, and can be reconfigured to measure different target molecules by exchanging probes in a modular manner. To demonstrate the system's versatility, we measured therapeutic in vivo concentrations of doxorubicin (a chemotherapeutic) and kanamycin (an antibiotic) in live rats and in human whole blood for several hours with high sensitivity and specificity at subminute temporal resolution. We show that MEDIC can also obtain pharmacokinetic parameters for individual animals in real time. Accordingly, just as continuous glucose monitoring technology is currently revolutionizing diabetes care, we believe that MEDIC could be a powerful enabler for personalized medicine by ensuring delivery of optimal drug doses for individual patients based on direct detection of physiological parameters.

Loss of glucocorticoid receptor from pro-inflammatory T cells after lung transplant

BACKGROUND

Pro-inflammatory cytokines in T and natural killer T (NKT)-like cells increase with time post-transplant in otherwise stable patients, suggesting that some patients become relatively resistant to immunosuppressants such as glucocorticoids (GC). We hypothesized that GC receptor (GCR) would be down-regulated in peripheral blood pro-inflammatory T and NKT-like cells after lung transplantation and loss of GCR would correlate with time post-transplant.

METHODS

Blood was collected from 17 stable lung transplant patients and 17 healthy, aged-matched controls. Intracellular GCR expression and pro-inflammatory cytokines were determined using flow cytometry.

RESULTS

There was a loss of GCR in CD8(+) and CD8(-) T and NKT-like cells in transplant patients compared with control subjects (transplants 37 ± 9%, controls 47 ± 12%; GCR(+)CD8(+) and CD8(-) T cells: transplants 39 ± 13%, controls 58 ± 13%). Loss of GCR was associated with a greater percentage of T cells producing interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) but not NKT-like cells. There was a correlation between the percentage of GCR-negative T cells with months post-transplant (R = 0.519, p = 0.033) and dose of prednisolone (R = 0.775, p = 0.038).

CONCLUSIONS

Time post-transplant and prednisolone dose correlate with loss of GCR in pro-inflammatory T cells in stable transplant patients, suggesting the need for reassessment of the long-term use of steroids after lung transplant in view of their attendant significant side effects.

Targeting peripheral blood pro-inflammatory CD28null T cells and natural killer T-like cells by inhibiting CD137 expression: possible relevance to treatment of bronchiolitis obliterans syndrome

BACKGROUND

We have shown that bronchiolitis obliterans syndrome (BOS) is associated with attenuated suppression of pro-inflammatory cytokines and granzyme B by steroid-resistant peripheral blood CD28nullCD137+ T cells and natural killer T (NKT)-like cells. We hypothesized that we could target these steroid-resistant lymphocytes by inhibiting costimulation through CD137.

METHODS

Isolated peripheral blood mononuclear cells from transplant patients with stable lung function, patients with BOS, and healthy controls were stimulated with anti-CD3 with and without blocking anti-CD137 and with and without 10(-6) mol/liter methylprednisolone (MP) (with and without stimulatory anti-CD137). Pro-inflammatory cytokine profiles and expression of the cytotoxic mediator, granzyme B, by CD28null T and NKT-like cells were determined using flow cytometry.

RESULTS

There was a significant decrease in the percentage of CD28null T and NKT-like cells producing interferon (IFN)-γ, tumor necrosis factor (TNF)-α, and granzyme B in all individuals in the presence of anti-CD137 blocking antibody compared with anti-CD3 alone (eg, 30% decrease in CD8+CD28null TNF-α+ cells). Stimulatory anti-CD137 was associated with an increase in pro-inflammatory/cytotoxic cells. Treatment with anti-CD137 blocking with prednisolone further reduced IFN-γ, TNF-α, and granzyme B in these cells.

CONCLUSIONS

Blocking CD137 expression in CD28null T cells and NKT-like cells is associated with down-regulation of IFN-γ, TNF-α, and granzyme B. Targeting CD137 reduces pro-inflammatory/cytotoxic expression in steroid-resistant CD28null T and NKT-like cells and may have therapeutic implications for patients with BOS.

Up-regulation of alternate co-stimulatory molecules on proinflammatory CD28null T cells in bronchiolitis obliterans syndrome

Bronchiolitis obliterans syndrome (BOS) is associated with lack of immunosuppression of T cell proinflammatory cytokines and increased T cell granzyme B. Repeated antigen-driven proliferation down-regulates T cell CD28. We hypothesized that down-regulation of CD28 and up-regulation of alternate co-stimulatory molecules (CD134, CD137, CD152 and CD154) on T cells may be associated with BOS. Co-stimulatory molecules, granzyme B, perforin and intracellular cytokines were measured by flow cytometry on T cells from stable lung transplant patients (n = 38), patients with BOS (n = 20) and healthy controls (n = 10). There was a significant increase in the percentage of CD4/28(null) and CD8/28(null) T cells producing granzyme B, interferon (IFN)-γ and tumour necrosis factor (TNF)-α in BOS compared with stable patients. Down-regulation of CD28 was associated with steroid resistance and up-regulation of CD134, CD137, CD152 and CD154 on CD4(+) T cells and CD137 and CD152 on CD8(+) T cells. There was a significant correlation between increased CD28(null) /CD137 T cells producing IFN-γ, TNF-α with BOS grade (r = 0·861, P < 0·001 for CD28(null) /CD137 IFN-γ/CD8) and time post-transplant (r = 0·698, P < 0·001 for CD28(null) /CD137 IFN-γ/CD8). BOS is associated with down-regulation of CD28 and up-regulation of alternate co-stimulatory molecules on steroid-resistant peripheral blood proinflammatory CD4(+) and CD8(+) T cells. Therapeutic targeting of alternate co-stimulatory molecules on peripheral blood CD28(null) T cells and monitoring response using these assays may help in the management of patients with BOS.

Increased natural killer T-like cells are a major source of pro-inflammatory cytokines and granzymes in lung transplant recipients

BACKGROUND AND OBJECTIVE

Natural killer T (NKT)-like cells are a small but significant population of T lymphocytes; however, their role in lung transplant and the effect of current immunosuppressive agents on their function is largely unknown. We have previously shown lung transplant rejection was associated with an increase in peripheral blood T cell γ-interferon (IFN-γ), tumour necrosis factor-α (TNF-α) and granzyme B. NKT-like cells are a source of these pro-inflammatory mediators and as such may be involved in lung transplant pathology.

METHODS

We analysed NKT-like cell numbers and cytokine and granzyme profiles in peripheral blood from a group of stable lung transplant patients and control subjects using multiparameter flow cytometry.

RESULTS

There was a significant increase in NKT-like cells in transplant patients compared with control subjects (6.8 ± 4.9 vs 0.8 ± 0.2% lymphocytes respectively). There was an increase in the numbers of NKT-like cells producing IFN-γ, TNF-α, IL-2 IL-17, granzyme and perforin in transplant patients compared with controls. Immunosuppressant drugs were less effective at inhibiting IFN-γ and TNF-α production by T and NKT-like cells than NK cells in vitro.

CONCLUSIONS

Current therapeutics is inadequate at suppressing NKT-like cell numbers and their production of pro-inflammatory mediators known to be associated with graft rejection. Alternative therapies that specifically target NKT-like cells may improve patient morbidity.

Time post-lung transplant correlates with increasing peripheral blood T cell granzyme B and proinflammatory cytokines

Immunosuppression therapy following lung transplant fails to prevent chronic rejection/bronchiolitis obliterans syndrome, which we have shown is associated with lack of suppression of peripheral blood T cell granzyme B, interferon (IFN)-γ and tumour necrosis factor (TNF)-α. We hypothesized that these proinflammatory mediators may increase with time post-transplant in otherwise stable patients before clinical signs of declining lung function, and patients experiencing declining lung function would show a further increase in these mediators. Intracellular cytokine profiles and granzyme B were investigated in T cells in whole blood and airways from lung transplant patients using flow cytometry. There was a significant negative correlation between forced expiratory volume in 1 s (FEV(1) ), drug dose and time post-transplant. A significant correlation between increased granzyme B, IFN-γ, interleukin (IL)-2 and TNF-α and time post-transplant was noted in peripheral blood T cells but not lung T cells from stable patients. Patients with similar drug dose but experiencing declining FEV(1) showed a further increase in peripheral blood T cell IFN-γ, IL-2 and TNF-α. Time post-lung transplant correlates with increasing peripheral blood T cell granzyme B and proinflammatory cytokines. Declining FEV(1) is associated with a further increase in these proinflammatory mediators. Drugs that reduce these inflammatory mediators effectively may reduce the incidence of chronic graft rejection.

Acute lung transplant rejection is associated with localized increase in T-cell IFNgamma and TNFalpha proinflammatory cytokines in the airways

BACKGROUND

Allograft rejection remains a major cause of morbidity and mortality after lung transplantation and is associated with increased gene expression for proinflammatory cytokines. T cells are a major cell type involved in graft rejection. There have been no previous studies of cytokine production by T cells from blood, bronchoalveolar lavage (BAL), and intraepithelial T cells from bronchial brushings (BB) during rejection episodes; we hypothesized that T-cell proinflammatory cytokines would be increased in the airways during rejection episodes despite standard immunosuppression regimens.

METHOD

To investigate changes in cytokine profiles during rejection episodes, whole blood, BAL, and BB from stable lung transplant patients and those with acute rejection were stimulated in vitro and intracellular cytokine production by CD8- (CD4+) and CD8+ T-cell subsets determined using multiparameter flow cytometry.

RESULTS

Transforming growth factor (TGF)-beta was significantly decreased in blood CD4+ and CD8+ T cells while interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha were significantly increased in BAL CD4+ and CD8+ T cells in patients with evidence of rejection. There was no change in CD4:CD8, interleukin (IL)-2, or IL-4 between stable and rejecting groups.

CONCLUSIONS

Acute lung transplant rejection is associated with decreased intracellular T-cell TGFbeta in blood and increased intracellular IFNgamma and TNFalpha in BAL CD4+ and CD8+ T cells. Drugs that effectively reduce airway T-cell IFNgamma and TNFalpha proinflammatory cytokine production may improve current protocols for reducing acute graft rejection in lung transplant patients.

Evidence for IFN-? up- and IL-4 downregulation late post-transplant in patients with good kidney graft outcome

We found recently that patients with good graft outcome showed higher IFN-gamma and IL-2, and lower IL-10 plasma levels late post-transplant than early post-transplant. In this retrospective study, we compared cytokine plasma levels in 33 symptom-free outpatients with those of 33 renal transplant recipients with early acute rejection (EAR), 29 with chronic rejection (CR), and 34 healthy controls (HC) to assess whether there is evidence for Th1 activation late post-transplant in patients with good graft outcome. Cytokines were measured pre-transplant, one wk, one month, six months, one yr, and two yr after transplantation. Twelve and 24 months post-transplant, IFN-gamma plasma levels were significantly higher (p = 0.001; p = 0.001, respectively) and IL-4 plasma levels significantly lower (p = 0.028; p = 0.003, respectively) in patients with stable graft function than those in controls. Six, 12, and 24 months post-transplant, patients with stable graft function had similar IFN-gamma and IL-4 plasma levels as patients with successfully treated EAR (p = n.s.), and higher IFN-gamma (p = 0.013; p = 0.001; p = 0.0005, respectively) and lower IL-4 (p = 0.007; p = 0.417; p = 0.0001, respectively) plasma levels than patients with CR. These data suggest that increased plasma IFN-gamma and decreased plasma IL-4 late post-transplant might be involved in the induction of mechanisms that facilitate good long-term graft outcome.

Airway infection in stable lung transplant patients is associated with decreased intracellular T-helper type 1 pro-inflammatory cytokines in bronchoalveolar lavage T-cell subsets

Current immunosuppression protocols to prevent lung transplant rejection reduce pro-inflammatory and T-helper type 1 (Th1) cytokines. However, Th1 T-cell pro-inflammatory cytokine production is important in host defense against bacterial infection in the lungs. Excessive immunosuppression of Th1 T-cell pro-inflammatory cytokines leaves patients susceptible to infection. To investigate whether pulmonary infection in lung transplant recipients is associated with reduced Th1 T-cell pro-inflammatory cytokines, whole blood and bronchoalveolar lavage (BAL) fluid from 13 stable lung transplant patients with 'culture-negative' BAL and 13 patients with 'culture-positive' BAL was stimulated in vitro, and cytokine production by CD8+ and CD4+ T-cell subsets was determined using multiparameter flow cytometry. In BAL samples, there was a significant decrease in interleukin-2 (IL2) in CD3+ T cells and tumor necrosis factor-alpha (TNF-alpha) in CD8+ T cells (but not CD4+) in 'culture-positive' compared with 'culture-negative' transplant patients. There was no difference in blood Th1 T-cell cytokines between 'culture-positive' compared with 'culture-negative' transplant patients. A decrease in Th1 cytokines IL-2 and TNF-alpha in BAL T-cell subsets is associated with isolation of potentially pathogenic organisms in the lungs in stable lung transplant patients. Excessive immunosuppression of these Th1 T-cell pro-inflammatory cytokines in stable transplant patients may leave them susceptible to infection. Modifying immunosuppression by monitoring intracellular Th1 pro-inflammatory cytokines in BAL T cells may help to improve morbidity and infection rates in stable lung transplant patients.

Compartmentalization of intracellular proinflammatory cytokines in bronchial intraepithelial T cells of stable lung transplant patients

Allograft rejection remains a major cause of morbidity and mortality following lung transplantation and is associated with an increased expression of T cell proinflammatory cytokines. We have shown that CD4(+) T cell proinflammatory cytokine production was significantly reduced in peripheral blood and bronchoalveolar lavage (BAL) of stable lung transplant patients, consistent with immunosuppression therapy. However, analysis of inflammatory cytokine profiles of intraepithelial T cells in bronchial brushing (BB) may be more relevant than peripheral blood or BAL T cells for assessing immune graft status. To investigate the immunomodulatory effects of currently used immunosuppressive regimens on bronchial intraepithelial T cell cytokine production, whole blood, BAL and BB from stable lung transplant patients and control volunteers were stimulated in vitro and cytokine production by CD8(+) and CD4(+) T cell subsets determined using multi-parameter flow cytometry. In bronchial intraepithelial T cell subsets in control subjects and transplant patients there was compartmentalization of interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha production, a decrease in interleukin (IL)-2 production by CD4(+) T cells and CD4 : CD8 inversion compared with blood and BAL. Although there was a decrease in T cell proinflammatory cytokine production in blood of transplant patients, this was not found in BAL or bronchial intraepithelial CD8 T cell subsets, suggesting that the same level of immunosuppression may not occur in the lung of transplant recipients. Drugs that effectively reduce CD8 T cell proinflammatory cytokine production in the lung compartment may improve current protocols for reducing graft rejection in these patients.

Cytokine analysis to predict immunosuppression

BACKGROUND

Recently, it has been realized that TH1/TH2 cytokine production offer the unique possibility to predict drug efficacy. However, there is still an incessant need to explore assay conditions and techniques of analyzing cytokines, which are specific and reliable for monitoring drug efficacy.

METHODS

In this study we used the multiplex bead array technique to detect cytokines of TH1/TH2 cells in whole blood of heart transplanted (HTx) recipients.

RESULTS

We found significantly different levels of cytokine expression in HTx recipients compared with cytokine levels in patients prior to HTx. Furthermore, particular cytokine levels were significantly decreased 2 h after drug dosing, compared with cytokine levels before dosing in mitogen-stimulated whole blood.

CONCLUSIONS

Cytokine analysis with the multiplex array technique in mitogen-stimulated whole blood provides the possibility to predict immunosuppression.