Intracellular cytokines in blood T cells in lung transplant patients--a more relevant indicator of immunosuppression than drug levels

Immune dysregulation as a driver of bronchiolitis obliterans

Bronchiolitis obliterans (BO) is a disease characterized by airway obstruction and fibrosis that can occur in all age groups. Bronchiolitis obliterans syndrome (BOS) is a clinical manifestation of BO in patients who have undergone lung transplantation or hematopoietic stem cell transplantation. Persistent inflammation and fibrosis of small airways make the disease irreversible, eventually leading to lung failure. The pathogenesis of BO is not entirely clear, but immune disorders are commonly involved, with various immune cells playing complex roles in different BO subtypes. Accordingly, the US Food and Drug Administration (FDA) has recently approved several new drugs that can alleviate chronic graft-versus-host disease (cGVHD) by regulating the function of immune cells, some of which have efficacy specifically with cGVHD-BOS. In this review, we will discuss the roles of different immune cells in BO/BOS, and introduce the latest drugs targeting various immune cells as the main target. This study emphasizes that immune dysfunction is an important driving factor in its pathophysiology. A better understanding of the role of the immune system in BO will enable the development of targeted immunotherapies to effectively delay or even reverse this condition.

Impaired immune responses and prolonged viral replication in lung allograft recipients infected with SARS-CoV-2 in the early phase after transplantation

PURPOSE

Lung transplant recipients are at increased risk of severe disease following infection with severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) due to high-dose immunosuppressive drugs and the lung is the main organ affected by Coronavirus disease 2019 (COVID-19). Several studies have confirmed increased SARS-CoV-2-related mortality and morbidity in patients living with lung allografts; however, detailed immunological studies of patients with SARS-CoV-2 infection in the early phase following transplantation remain scarce.

METHODS

We investigated patients who were infected with SARS-CoV-2 in the early phase (18-103 days) after receiving double-lung allografts (n = 4, LuTx) in comparison to immunocompetent patients who had not received solid organ transplants (n = 88, noTx). We analyzed SARS-CoV-2-specific antibody responses against the SARS-CoV-2 spike and nucleocapsid proteins using enzyme-linked immunosorbent assays (ELISA), chemiluminescence immunoassays (CLIA), and immunoblot assays. T cell responses were investigated using Elispot assays.

RESULTS

One LuTx patient suffered from persistent infection with fatal outcome 122 days post-infection despite multiple interventions including remdesivir, convalescent plasma, and the monoclonal antibody bamlanivimab. Two patients experienced clinically mild disease with prolonged viral shedding (47 and 79 days), and one patient remained asymptomatic. Antibody and T cell responses were significantly reduced or undetectable in all LuTx patients compared to noTx patients.

CONCLUSION

Patients in the early phase following lung allograft transplantation are vulnerable to infection with SARS-CoV-2 due to impaired immune responses. This patient population should be vaccinated before LuTx, protected from infection post-LuTx, and in case of infection treated generously with currently available interventions.

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.

Therapeutic Targeting Steroid Resistant Pro-Inflammatory NK and NKT-Like Cells in Chronic Inflammatory Lung Disease

The innate immune system drives the initiation of inflammation and progression to chronic inflammation in two important chronic inflammatory lung diseases involving the small airways, chronic obstructive pulmonary disease (COPD) and bronchiolitis obliterans syndrome (BOS), following lung transplantation. Recently natural killer T cell like (NKT-like) cells, which represent a bridge between the innate and adaptive immune response as well as the innate natural killer cell (NK) cells, have been shown to be important cells in these two chronic lung diseases. Importantly these cells have been shown to be resistant to commonly used anti-inflammatory drugs such as glucocorticoids and as such their inflammatory nature has been difficult to suppress. Mechanisms leading to steroid resistance in both diseases has recently been shown. Glucocorticoids switch off inflammatory genes by first entering the cell and binding to glucocorticoid receptors (GCRs). The steroid-GCR complex must then be chaperoned into the nucleus via several heat shock proteins, where they engage histone deacetylase 2 to switch off pro-inflammatory gene transcription. Many of these mechanisms are altered in NK and NKT-like cells in COPD and BOS requiring novel intervention using combinations of currently available drugs. Evidence will be presented to show how these drugs can overcome these mechanisms of drug resistance ex vivo advising novel therapeutic strategies for the treatment these two important chronic inflammatory lung diseases.

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.

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.

Molecular Diagnostics of Calcineurin-Related Pathologies

BACKGROUND

The Ca2+-dependent protein phosphatase enzyme calcineurin (Cn) (protein phosphatase 3) is best known for its role as director of the adaptive immune response. One of its principal substrates is the nuclear factor of activated T cells (NFAT), which translocates to the nucleus after dephosphorylation to mediate gene transcription. Drugs targeting Cn (the Cn inhibitors tacrolimus and cyclosporin A) have revolutionized posttransplantation therapy in allograft recipients by considerably reducing rejection rates.

CONTENT

Owing primarily to intensive study of the side effects of the Cn inhibitors, the unique importance of Cn and Cn/NFAT signaling in the normal physiological processes of many other cell and tissue types is becoming more evident. During the last decade, it has become clear that an extensive and diverse array of clinical conditions can be traced back, at least in part, to a disturbed Cn-signaling axis. Hence, both diagnostics and therapeutic monitoring could benefit from a technique that conveniently reads out Cn/NFAT operative status.

SUMMARY

This review outlines the current knowledge on the pathologic conditions that have calcineurin as a common denominator and reports on the progress that has been made toward successfully applying Cn and Cn/NFAT activity markers in molecular diagnostics.

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.

JC virus T-Antigen DNA in gastrointestinal mucosa of immunosuppressed patients: a prospective, controlled study

BACKGROUND

JC virus (JCV), a polyoma virus, is the etiological agent of progressive multifocal leukoencephalopathy in immunosuppressed patients. JCV T-Ag has proven oncogenic potential and is expressed in colonic polyps and carcinomas. We proposed that the prevalence of JCV T-Ag DNA is higher in the normal gastrointestinal (GI) mucosa of immunosuppressed patients compared with their immunocompetent counterparts.

AIMS

To look for JCV T-Ag DNA in the normal gastrointestinal mucosa of immunosuppressed patients compared with immunocompetent controls.

METHODS

Macroscopically normal samples of upper and lower GI mucosa were obtained from 38 immunosuppressed patients. A control group included samples from 19 immunocompetent inflammatory bowel disease (IBD) and 29 non-IBD cases. DNA was extracted and polymerase chain reaction (PCR) was performed using primers specific for T-Ag.

RESULTS

JCV T-Ag DNA was found in nine of the immunosuppressed patients (23.7%) and in three of the controls (6.3%; P = 0.02). Transplant recipients had a particularly high prevalence of JCV T-Ag DNA (35.3%). Patients with IBD receiving immunosuppressive drugs had a higher prevalence of JCV T-Ag DNA in comparison with IBD patients who did not receive immunosuppression (22.2% versus 10.5%, respectively), but this difference was not statistically significant (P = 0.574).

CONCLUSION

JCV T-Ag DNA is more prevalent in the upper and lower GI mucosa of immunosuppressed patients, possibly indicating that the virus resides in these patients. This may account for the higher prevalence of GI carcinomas in immunosuppressed patients.

Pharmacodynamic monitoring of calcineurin inhibition therapy: principles, performance, and perspectives

The calcineurin inhibitors (CNIs) cyclosporin A and tacrolimus are immunosuppressive drugs used extensively in allograft recipients. These drugs show large interindividual pharmacokinetic variation and are associated with severe adverse affects, including nephrotoxicity and cardiovascular disease. In current practice, CNIs are combined with other immunosuppressive drugs such as steroids and mycophenolate mofetil. Dosage is titrated based on blood concentration measurement. For further optimization of calcineurin (CN) inhibition therapy, new monitoring strategies are required. Pharmacodynamic-monitoring strategies constitute novel approaches for optimization of CNIs therapy. This review focuses on the general aspects of immunosuppressive drug pharmacodynamic monitoring and describes the methodologies used for monitoring CN inhibition therapy. Two different types of pharmacodynamic-monitoring strategies can be distinguished: (1) enzymatic strategies, which monitor inhibition of drug-target enzyme activity, and (2) immunologic strategies, which measure cellular responsiveness after in vitro simulated immunologic responses. Enzymatic tests are drug type-specific markers in which CN activity is directly determined. Immunologic strategies measure immune responsiveness at several levels, such as mRNA transcripts (intracellular) concentrations/excretion of cytokines, expression of surface activation markers, and cell proliferation. This review also discusses analytical issues and clinical experience with these techniques. The call for new methodologies to evaluate immunosuppressive therapy has led to the development of a large variety of pharmacodynamic-monitoring strategies. The first reports of their clinical relevance are available, but further understanding of the analytical and clinical variables involved are required for the development of accurate, reproducible, and clinically relevant markers.

Garlic compounds selectively kill childhood pre-B acute lymphoblastic leukemia cells in vitro without reducing T-cell function: Potential therapeutic use in the treatment of ALL

Drugs used for remission induction therapy for childhood precursor-B acute lymphoblastic leukemia (ALL) are nonselective for malignant cells. Several garlic compounds have been shown to induce apoptosis of cancer cells and to alter lymphocyte function. To investigate the effect of garlic on the apoptosis of ALL cells and lymphocyte immune function, cells from newly diagnosed childhood ALL patients were cultured with several commonly used chemotherapeutic agents and several garlic compounds. Apoptosis, lymphocyte proliferation and T-cell cytokine production were determined using multiparameter flow cytometry. At concentrations of garlic compounds that did not result in significant increases in Annexin V and 7-AAD staining of normal lymphocytes, there was a significant increase in apoptosis of ALL cells with no alteration of T-cell proliferation as determined by CD25/CD69 upregulation or interferonγ, interleukin-2 or tumor necrosis factor-α intracellular cytokine production. In contrast, the presence of chemotherapeutic agents resulted in nonselective increases in both lymphocyte and ALL apoptosis and a decrease in T-cell proliferation and cytokine production. In conclusion, we show selective apoptosis of malignant cells by garlic compounds that do not alter T-cell immune function and indicate the potential therapeutic benefit of garlic compounds in the treatment of childhood ALL.

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.

Increased intracellular T helper 1 proinflammatory cytokine production in peripheral blood, bronchoalveolar lavage and intraepithelial T cells of COPD subjects

The role of T cells in the pathophysiology of chronic obstructive pulmonary disease (COPD) is not yet certain, although varying reports have shown increases in T helper 1 (Th1) and/or Th2 cytokines in peripheral blood and bronchoalveolar lavage (BAL). No studies have examined cytokine production by intraepithelial T cells obtained by bronchial brushing (BB). Intracellular cytokine analysis of T cell subsets from peripheral blood, BAL and BB from smoker and ex-smoker COPD patients, COPD patients receiving inhaled corticosteroids and smoker and non-smoker control subjects was studied using multi-parameter flow cytometry. CD4 : CD8 inversion was noted in the peripheral blood of smoker and ex-smoker COPD groups, in BAL and BB from smoker controls and BAL of COPD smokers. There was an increase in intracellular CD8(+) T cell Th1 proinflammatory cytokines in some COPD groups in the peripheral blood and in CD8(+) T cell tumour necrosis factor (TNF)-alpha in some COPD groups and smoker controls in BAL and BB. There was an increase in proinflammatory cytokines in COPD smokers compared with ex-smokers and a decrease in COPD smokers receiving inhaled corticosteroids in the airways. There was a negative correlation between forced expiratory volume in 1 s (FEV(1)) and the percentage of BAL and intraepithelial CD8(+) T cells producing TNF-alpha. COPD patients exhibit systemic inflammation as evidenced by increased intracellular Th1 proinflammatory cytokines in blood, BAL and intraepithelial CD8(+) T cells, whereas smoker controls showed localized Th1 response in the lung only. Systemic therapeutic targeting of TNF-alpha production by CD8(+) T cells may improve morbidity in COPD patients while targeting of TNF-alpha in the lung may prevent smokers progressing to COPD.

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.

Pharmacodynamics of T-cell function for monitoring immunosuppression

OBJECTIVES

Recent studies show that measuring pharmacodynamic (PD) effects offers a unique possibility to predict immunosuppression. Thus, in this study we have monitored the PD properties of immunosuppressants on diverse T-cell functions in heart transplant (HTx) recipients.

MATERIALS

PDs and blood concentrations (PK) of three different basis-immunosuppressive drugs were studied: cyclosporin A (CsA); tacrolimus (TRL) and sirolimus (SRL). T-cell function was analysed by expression of proliferating cell nuclear antigen (PCNA) labelling, expression of cytokines (IL-2, IFN-gamma) and surface antigen (for example, CD25) by FACS analysis.

RESULTS

In group I, at time points C0 and C2, increased CsA-PK significantly inhibited expression of IL-2, IFN-gamma, PCNA and CD25 (P < 0.05). Correlations (r(2)) at C2 between inhibition of T-cell functions (PD) with PK and with drug doses were: CsA-PK: 0.71-0.91 and CsA-dose: 0.73-0.87. In group II, increased TRL-PK over time did not further inhibit expression of CD25, but inhibited PCNA expression more on day 3, and IL-2 and IFN-gamma expression was significantly higher on days 2 and 3 compared to PD effects of CsA (P < 0.05). Blood SRL concentrations in C0 group III, increased on day 1 and remained stable at days 3 and 4. Expression of PCNA was not altered in the SRL-PK category, whereas expression of CD25 was higher and expression of cytokines was lower than PD effects of CsA.

CONCLUSIONS

Our results show that PD effects on T-cell function can be used to monitor immunosuppression bringing potential to increase the efficacy and safety of immunosuppressive therapy after HTx.

Pin1 modulates the type 1 immune response

Background/Abstract

Immune responses initiated by T cell receptor (TCR) and costimulatory molecule mediated signaling culminate in maximal cytokine mRNA production and stability. The transcriptional responses to co-stimulatory T cell signalling involve calcineurin and NF-AT, which can be antagonized by interference with the cis-trans peptidyl-prolyl isomerases (PPIase), cyclophilin A and FKBP. Signalling molecules downstream of CD28 which are essential for the stabilization of cytokine mRNAs are largely unknown.

Methodology/Principal Findings

We now show that Pin1, a third member of the PPIase family mediates the post-transcriptional regulation of Th1 cytokines by activated T cells. Blockade of Pin1 by pharmacologic or genetic means greatly attenuated IFN-γ, IL-2 and CXCL-10 mRNA stability, accumulation and protein expression after cell activation. In vivo, Pin1 blockade prevented both the acute and chronic rejection of MHC mismatched, orthotopic rat lung transplants by reducing the expression of IFN-γ and CXCL-10. Combined transcriptional and post-transcriptional blockade with cyclosporine A and the Pin1 inhibitor, juglone, was synergistic.

Conclusions/Significance

These data suggest Pin1 inhibitors should be explored for use as immunosuppressants and employed with available calcineurin inhibitors to reduce toxicity and enhance effectiveness.

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.

Increased intracellular pro- and anti-inflammatory cytokines in bronchoalveolar lavage T cells of stable lung transplant patients

BACKGROUND

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 recently shown that peripheral blood T-cell proinflammatory cytokine production was significantly reduced in stable lung transplant patients consistent with immunosuppression therapy. However, analysis of inflammatory cytokine profiles in bronchoalveolar lavage (BAL) T cells may be more relevant than peripheral blood T cells for assessing graft status.

METHODS

To investigate the immunomodulatory effects of currently used immunosuppressive regimens on BAL T-cell cytokine production, whole blood and BAL from stable lung transplant patients and control volunteers was stimulated in vitro and cytokine production by CD8+ and CD4+ T-cell subsets determined using multiparameter flow cytometry.

RESULTS

There was a significant decrease in T-cell proinflammatory cytokine production in BAL compared with blood from control subjects but not transplant patients. Anti-inflammatory cytokine IL-4 was increased in BAL compared with blood from both groups. There was a significant increase in IFNgamma, IL-2, IL-4, TGFbeta, and TNFalpha production by CD8 T cells and IFNgamma and TNFalpha production by CD4 T cells in BAL from transplant patients compared with controls.

CONCLUSIONS

We have shown decreased T-cell pro- and anti-inflammatory cytokine production in BAL compared with blood in control subjects but not in stable lung transplant patients. Current immunosuppression protocols have limited effect on T-cell proinflammatory cytokine production in BAL but do upregulate anti-inflammatory cytokines IL-4 and TGFbeta. Drugs that effectively reduce T-cell proinflammatory cytokine production in BAL may improve current protocols for reducing graft rejection in these patients.