Efficacy of inhaled cyclosporine in lung transplant recipients with refractory rejection: correlation of intragraft cytokine gene expression with pulmonary function and histologic characteristics

Cyclosporine CsA—The Physicochemical Characterization of Liposomal and Colloidal Systems

This paper presents an overview of the possibilities of testing various cyclosporine (CsA) formulations with an emphasis on parameters that may be key to improving the stability and biocompatibility. The feasibility of CsA colloidal systems for oral (injection) administration were investigated using different techniques and compared with similar investigations of other researchers. The chosen CsA systems were developed using dipalmitoylphosphocholine (DPPC) and/or cholesterol as a lipid matrix, stabilized with ethanol, with soybean oil or n-tetradecane as oil phase in emulsions, under natural pH, room and physiological temperature. Their integrity was found to be strictly dependent on the stabilizers. The highest CsA penetrability with the system containing phospholipid in the context of its interactions with lipid membranes was shown. Also, the bioavailability of CsA can be enhanced with the biopolymer antibacterial chitosan. This mini-review suggests the suitability of liposome/microemulsion as promising vehicles for CsA delivery. The most hopeful proved to be formulation with the smaller particle size facilitating absorption, but when safety is assessed, relying on just the particle size cannot be the only criteria. Reassumed, the CsA formulation stability known on the basis of the size and zeta potential measurements guarantees a decrease of the individual variations in the drug bioavailability, toxicity and minimizes rejection.

A randomised single-centre trial of inhaled liposomal cyclosporine for bronchiolitis obliterans syndrome post-lung transplantation

Introduction

No proven treatments exist for bronchiolitis obliterans syndrome (BOS) following lung transplantation. Inhaled liposomal cyclosporine (L-CsA) may prevent BOS progression.

Methods

A 48-week phase IIb randomised clinical trial was conducted in 21 lung transplant patients with BOS assigned to either L-CsA with standard-of-care (SOC) oral immunosuppression (L-CsA group) or SOC (SOC-alone group). Efficacy end-points were BOS progression-free survival (defined as absence of ≥20% decline in forced expiratory volume in 1 s (FEV₁) from randomisation, re-transplantation or death) and BOS grade change.

Results

BOS progression-free survival was 82% for L-CsA versus 50% for SOC-alone (p=0.1) and BOS grade worsened in 18% for L-CsA versus 60% for SOC-alone (p=0.05). Mean changes in ΔFEV₁ and forced vital capacity, respectively, stabilised with L-CsA: +0.005 (95% CI −0.004– +0.013) and −0.005 (95% CI −0.015– +0.006) L·month⁻¹, but worsened with SOC-alone: −0.023 (95% CI −0.033– −0.013) and −0.026 (95% CI −0.039– −0.014) L·month⁻¹ (p<0.0001 and p=0.009). Median survival (4.1 versus 2.9 years; p=0.03) and infection rate (45% versus 60%; p=0.7) improved with L-CsA versus SOC-alone; creatinine and tacrolimus levels were similar.

Conclusions

L-CsA was well tolerated and stabilised lung function in lung transplant recipients affected by BOS without systemic toxicity, providing a basis for a global phase III trial using L-CsA.

Liposomal aerosol cyclosporine (L-CsA) was well tolerated and stabilised lung function in lung transplant recipients affected by BOS. The data provide evidence for an ongoing global phase III trial using L-CsA for BOS.http://bit.ly/2HB8w5j

Immunosuppression and allograft rejection following lung transplantation: evidence to date

The enduring success of lung transplantation is built on the use of immunosuppressive drugs to stop the immune system from rejecting the newly transplanted lung allograft. Most patients receive a triple-drug maintenance immunosuppressive regimen consisting of a calcineurin inhibitor, an antiproliferative and corticosteroids. Induction therapy with either an antilymphocyte monoclonal or an interleukin-2 receptor antagonist are prescribed by many centres aiming to achieve rapid inhibition of recently activated and potentially alloreactive T lymphocytes. Despite this generic approach acute rejection episodes remain common, mandating further fine-tuning and augmentation of the immunosuppressive regimen. While there has been a trend away from cyclosporine and azathioprine towards a preference for tacrolimus and mycophenolate mofetil, this has not translated into significant protection from the development of chronic lung allograft dysfunction, the main barrier to the long-term success of lung transplantation. This article reviews the problem of lung allograft rejection and the evidence for immunosuppressive regimens used both in the short- and long-term in patients undergoing lung transplantation.

Inhalable dry-emulsion formulation of cyclosporine A with improved anti-inflammatory effects in experimental asthma/COPD-model rats

The main purpose of the present study was to develop a novel respirable powder (RP) formulation of cyclosporine A (CsA) using a spray-dried O/W-emulsion (DE) system. DE formulation of CsA (DE/CsA) was prepared by spray-drying a mixture of erythritol and liquid O/W emulsion containing CsA, polyvinylpyrrolidone, and glyceryl monooleate as emulsifying agent. The DE/CsA powders were mixed with lactose carriers to obtain an RP formulation of DE/CsA (DE/CsA-RP), and its physicochemical, pharmacological, and pharmacokinetic properties were evaluated. Spray-dried DE/CsA exhibited significant improvement in dissolution behavior with ca. 4500-fold increase of dissolution rate, and then, nanoemulsified particles were reconstituted with a mean diameter of 317 nm. Laser diffraction analysis on the DE/CsA-RP suggested high dispersion of DE/CsA on the surface of the lactose carrier. Anti-inflammatory properties of the inhaled DE/CsA-RP were characterized in antigen-sensitized asthma/COPD-model rats, in which the DE/CsA-RP was more potent than the RP formulation of physical mixture containing CsA and erythritol in inhibiting inflammatory responses, possibly due to the improved dissolution behavior. Pharmacokinetic studies demonstrated that systemic exposure of CsA after intratracheal administration of the DE/CsA-RP at a pharmacologically effective dose (100 μg-CsA/rat) was 50-fold less than that of the oral CsA dosage form at a toxic dose (10 mg/kg). From these findings, use of inhalable DE formulation of CsA might be a promising approach for the treatment of airway inflammatory diseases with improved pharmacodynamics and lower systemic exposure.

In vitro and in vivo characterization on amorphous solid dispersion of cyclosporine A for inhalation therapy

Cyclosporine A (CsA) has been clinically used as immunosuppressant, and new application for airway inflammation was also proposed. However, the clinical use of CsA was limited due to severe adverse effects after systemic exposure and the poor solubility. In the present investigation, novel respirable powder (RP) of CsA was developed for pulmonary administration with use of solid dispersion of wet-milled CsA (WM/CsA), and the physicochemical and pharmacological properties of the WM/CsA and its RP formulation were characterized. CsA in the solid dispersion was found to be amorphous by X-ray powder diffraction and differential scanning calorimetry. It exhibited the improved dissolution behavior as compared to active pharmaceutical ingredients. Laser diffraction and cascade impactor analysis of newly developed WM/CsA-RP, consisting of jet-milled WM/CsA and lactose carriers, suggested high dispersion and deposition in the respiratory organs with the emitted dose and the fine particle fraction of 96 and 54%, respectively. Intratracheal administration of WM/CsA-RP (100 microg CsA) in experimental inflammatory rats led to 71 and 85% reduction of granulocyte recruitment in bronchoalveolar lavage fluids and lung tissues, respectively, with showing ca 10(2)-fold reduced AUC and C(max) values of plasma CsA as compared to the oral dosage form of CsA at toxic concentration (10 mg/kg). Upon these findings, WM/CsA-RP would be efficacious dosage form for clinical treatment of airway inflammations with minimal systemic side effects.

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.

Inhaled delivery of aerosolized cyclosporine

Aerosolized cyclosporine was the first calcineurin inhibitor to be developed for inhaled administration. Its use as a topical immunosuppressant after lung transplantation is reviewed. Animal studies in transplant and non-transplant models are considered, as is nebulized delivery of the drug, including the results of scintigraphy and pharmacokinetic studies. Open label clinical studies of the drug for the treatment of chronic and acute lung transplant rejection are detailed. Placebo controlled trials for rejection prophylaxis are described and future directions for the drug are considered. Aerosol cyclosporine provides an excellent example of how inhaled aerosol delivery can provide therapeutic concentrations of drug in the lungs while minimizing the side effects associated with high systemic concentrations. In the case of lung transplantation, the drug is delivered directly to the airways, the location of the pathology resulting in most mortality in this population (chronic allograft rejection), maximizing the efficacy of this dose-dependent immunosuppressant.

A randomized trial of inhaled cyclosporine in lung-transplant recipients

BACKGROUND

Conventional regimens of immunosuppressive drugs often do not prevent chronic rejection after lung transplantation. Topical delivery of cyclosporine in addition to conventional systemic immunosuppression might help prevent acute and chronic rejection events.

METHODS

We conducted a single-center, randomized, double-blind, placebo-controlled trial of inhaled cyclosporine initiated within six weeks after transplantation and given in addition to systemic immunosuppression. A total of 58 patients were randomly assigned to inhale either 300 mg of aerosol cyclosporine (28 patients) or aerosol placebo (30 patients) three days a week for the first two years after transplantation. The primary end point was the rate of histologic acute rejection.

RESULTS

The rates of acute rejection of grade 2 or higher were similar in the cyclosporine and placebo groups: 0.44 episode (95 percent confidence interval, 0.31 to 0.62) vs. 0.46 episode (95 percent confidence interval, 0.33 to 0.64) per patient per year, respectively (P=0.87 by Poisson regression). Survival was improved with aerosolized cyclosporine, with 3 deaths among patients receiving cyclosporine and 14 deaths among patients receiving placebo (relative risk of death, 0.20; 95 percent confidence interval, 0.06 to 0.70; P=0.01). Chronic rejection-free survival also improved with cyclosporine, as determined by spirometric analysis (10 events in the cyclosporine group and 20 events in the placebo group; relative risk of chronic rejection, 0.38; 95 percent confidence interval, 0.18 to 0.82; P=0.01) and histologic analysis (6 vs. 19 events, respectively; relative risk, 0.27; 95 percent confidence interval, 0.11 to 0.67; P=0.005). The risks of nephrotoxic effects and opportunistic infection were similar for patients in the cyclosporine group and the placebo group.

CONCLUSIONS

Inhaled cyclosporine did not improve the rate of acute rejection, but it did improve survival and extend periods of chronic rejection-free survival. (ClinicalTrials.gov number, NCT00268515.).

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.

A new class of cyclosporin analogues for the treatment of asthma

The disease management of asthma - in particular severe and steroid-resistant asthma - remains a real and daily challenge in the clinic. Cyclosporin A has been a mainstay of immunosuppression therapy in organ transplantation for many years. While its application clearly is efficacious in the inhibition of T-cell proliferation and results in the decrease of inflammatory processes, its side effects in long-term use manifested most prominently through nephrotoxicity have been the main concern against broader use of the drug in inflammatory and immune diseases other than organ transplantation. Several new strategies are currently being pursued to address cyclosporin A toxicity, as summarised in this review. The improved safety profile of novel cyclosporin analogues appear to promise potential new treatments of asthma.

Interleukin-6 and interferon-gamma gene polymorphisms in the development of bronchiolitis obliterans syndrome after lung transplantation

BACKGROUND

A number of genetic polymorphisms have been shown to regulate the production and secretion of tumor necrosis factor (TNF)-alpha, transforming growth factor (TGF)-beta1, interferon (IFN)-gamma, interleukin (IL)-6, and IL-10. Several of these genetic polymorphisms have been shown to be associated with either acute or chronic rejection of kidney, liver, and heart allografts and with development of allograft fibrosis after lung transplantation. The aim of this study was to assess the effect of these genetic polymorphisms on the development of bronchiolitis obliterans syndrome (BOS) after lung transplantation.

METHODS

Genetic polymorphisms were detected by means of polymerase chain reaction in 93 lung allograft recipients for functional polymorphisms in the TNF-alpha (-308), TGF-beta1 (+869 and +915), IL-6 (-174), IFN-gamma (+874), and IL-10 (-1082, -819, and -592) genes. Then, a correlation between BOS development and the presence of these cytokine genotypes was determined using Kaplan-Meier actuarial analysis.

RESULTS

A significant correlation was detected between the presence of high-expression polymorphisms of the IL-6 and IFN-gamma genes and BOS development after lung transplantation (P =0.045 and 0.039, respectively). Also, patients with high-expression polymorphisms in both genes developed BOS significantly earlier than patients with low-expression polymorphisms in one or both genes, suggesting a synergistic effect of the alleles during BOS pathogenesis (P =0.016). No correlation was detected between polymorphisms of the TNF-alpha, TGF-beta1, and IL-10 genes and development of BOS after lung transplantation.

CONCLUSIONS

The presence of high-expression polymorphisms at position -174 of the IL-6 gene and position +874 of the IFN-gamma gene significantly increases the risk for BOS development after lung transplantation.

Addition of inhaled corticosteroids to systemic immunosuppression after lung transplantation: a double-blind, placebo-controlled trial

BACKGROUND

It is postulated that bronchiolitis obliterans syndrome (BOS) is preceded by airway inflammation that has been described even in stable lung transplant recipients. Airway inflammation is known to be suppressed by inhaled steroids in other chronic inflammatory lung diseases, e.g., asthma and chronic obstructive pulmonary disease. BOS is the major cause of morbidity and mortality after lung transplantation.

OBJECTIVE

To examine the effect of inhaled corticosteroids on the development of BOS in lung transplant recipients.

METHODS

Thirty patients were recruited and randomized in a double-blind fashion to receive either 750 microg of fluticasone propionate (FP) or an identical-appearing placebo twice daily for 3 months; 20 of this group continued until 2 years posttransplantation. Detailed spirometry was performed regularly throughout the study.

RESULTS

In the short-term study no differences were found in any examined parameters. In the long-term component of the study no differences were found in the development of neither BOS nor survival. There were minor differences in bronchoalveolar lavage (BAL) lymphocyte percentages.

CONCLUSIONS

FP is ineffective for the prevention of BOS after lung transplantation despite the airway inflammation that characterizes this condition. Inadequate local delivery, timing of the therapy relative to transplantation and inherent steroid resistance of this condition may explain the negative finding of this study.

Effects of cyclosporin A administered into the airways against antigen-induced airway inflammation and hyperreactivity in the rat

The immunosuppressant cyclosporin A given orally has anti-asthma properties but carries an undesirable risk of systemic effects. We administered cyclosporin A to Brown Norway rats either orally (p.o.) or topically by intratracheal (i.t.) instillation into the airways before inhaled antigen. Cyclosporin A suppressed the antigen-induced accumulation of activated (CD25+) CD4+ T lymphocytes and eosinophils in the lung, interleukin-5 mRNA expression in lung tissue and airway hyperreactivity. Intratracheal cyclosporin A suppressed cell accumulation at a 10-fold lower dose than that required orally. Minimum effective doses were 3 mg x kg(-1) i.t. and 30 mg x kg(-1) p.o. Intratracheal administration reduced the plasma concentration and systemic exposure compared with an equieffective oral dose, but the reduction (4-5-fold) was not as large as anticipated. Our data suggests that although topical administration to asthmatics would provide some potential for an improved safety margin, it may not offer any major advantage over existing oral therapy. However, the data clearly demonstrate that a novel immunosuppressant with similar anti-inflammatory properties but reduced potential for systemic effects would offer an attractive therapy for severe asthma.

An unusual case of fatal pulmonary allograft rejection

This case report describes an atypical form of acute pulmonary allograft rejection that was refractory to conventional therapy. The rejection manifested primarily as interstitial lymphocytic infiltrates with little perivascular involvement. Despite aggressive therapy the patient died within 7 months of transplant. The timely recognition and treatment of unusual forms of allograft rejection is vital in the management of pulmonary transplant patients.

In the lung aerosol cyclosporine provides a regional concentration advantage over intramuscular cyclosporine

BACKGROUND

Acute rejection remains an almost universal complication among lung transplant recipients. Refractory rejection as well as chronic systemic immunosuppression is associated with significant morbidity and mortality. Recent studies suggest that aerosol cyclosporine may address these issues by effectively preventing acute cellular rejection while maintaining low systemic drug concentrations. This study was designed to evaluate the concentrations of cyclosporine in blood and lung tissue after aerosol and intramuscular administration.

METHODS

Lewis rats were divided into 4 experimental groups: Groups A (n = 33) and B (n = 30) received aerosol cyclosporine 3 and 5 mg/kg, respectively; Groups C (n = 33) and D (n = 30) received systemic cyclosporine 5 and 15 mg/kg, respectively. We used high-performance liquid chromatography to quantitate blood and lung tissue cyclosporine levels at timed intervals. We used the trapezoidal rule to approximate area under the concentration vs time curve (AUC).

RESULTS

Aerosol delivery of cyclosporine resulted in higher and more rapid peak drug levels in lung tissue samples than did systemic delivery. At an equivalent 5 mg/kg dose, the cyclosporine AUC was 3 times higher with aerosol delivery than with intramuscular delivery in lung tissue (477,965 vs 157,706 ng x hour/g, respectively). The lung tissue: blood AUC ratio was highest in the aerosol groups (27.3:1 and 17.4:1) compared with the intramuscular groups (8.1:1 and 9.4:1).

CONCLUSION

Local aerosol inhalation delivery of cyclosporine provides a regional advantage over systemic intramuscular therapy by providing higher peak concentrations and greater lung tissue exposure.

Successful treatment of acute, ongoing rat lung allograft rejection with the novel immunosuppressant SDZ-RAD

BACKGROUND

Recent experimental data have shown that coadministration of microemulsion cyclosporine and the novel immunosuppressant SDZ-RAD potentiates the immunosuppressive efficacies of both drugs to suppress allograft rejection. Our study was designed to assess the potential of delayed SDZ-RAD administration, in addition to cyclosporine maintenance therapy, to reverse acute rejection in an allogeneic rat lung transplant model.

METHODS

Unilateral left lung transplantation was performed using Brown-Norway donors implanted into Lewis recipients. An untreated control group and a cyclosporine monotherapy group (7.5 mg/kg) were followed for 7 days. An additional cyclosporine monotherapy group (7.5 mg/kg), and a combined therapy group treated with cyclosporine (7.5 mg/kg) plus SDZ-RAD (2.5 mg/kg), were followed for 21 days. For treatment of ongoing rejection, 7.5 mg/kg cyclosporine was given as maintenance therapy, and SDZ-RAD (2.5 mg/kg) was added on postoperative day 7. Drugs were given orally, and in the combined therapy regimens, administered 6 hours apart. Outcome variables included daily weight, radiographs, and histology.

RESULTS

Radiographs on postoperative day 7 showed mild and moderate opacification of the left chest in the cyclosporine monotherapy groups and the untreated control group. Addition of SDZ-RAD to cyclosporine treatment on postoperative day 7 reversed opacification by postoperative days 14 and 21. Monotherapy with microemulsion CsA resulted in mild histological rejection by day 7, which progressed to moderate rejection by day 21. Addition of SDZ-RAD on postoperative day 7 reversed acute rejection, resulting in none or minimal rejection at day 21.

CONCLUSIONS

SDZ RAD reverses acute rejection under cyclosporine maintenance therapy in a stringent lung allotransplant model.

Nebulizer-compatible liquid formulations for aerosol pulmonary delivery of hydrophobic drugs: glucocorticoids and cyclosporine

This review discusses pulmonary delivery of glucocorticoids and cyclosporine in pharmaceutically acceptable organic solvents and liposomes, as well as in micellar solutions and microemulsions, by means of liquid aerosols generated by nebulizers. The review points out the importance of a variety of parameters for successful treatment of immunologically mediated lung diseases by inhalation of drug containing aerosols with particular references to physico-chemical properties of formulations, aerosol parameters, pharmacokinetics, and lung deposition in experimental animals and humans. The prospects for the use of these types of formulations for clinical treatment of asthma, lung transplant rejection processes and other lung diseases are summarized.

Pharmacokinetics of liposomal aerosolized cyclosporine A for pulmonary immunosuppression

BACKGROUND

The results of pulmonary transplantation are compromised by acute and chronic rejection. We hypothesized that a liposomal form of aerosolized cyclosporine A (CsA) would be selectively deposited and concentrated in the lungs. The theoretical advantage of this therapy is selective pulmonary immunosuppression with prolonged utilization.

METHODS

Eighteen dogs were endotracheally intubated; aerosolized liposomal CsA was administered for 15 min. CsA levels were measured in whole blood, lung, trachea, heart, kidney, liver, and spleen at various times after treatment.

RESULTS

The lung rapidly absorbs aerosolized liposomal CsA; other organs have much lower concentrations. The retention of pulmonary CsA delivered by liposome aerosol is approximately 120 min in this model.

CONCLUSIONS

Aerosolized liposomal CsA is selectively deposited and concentrated in the lungs; other organs absorb less CsA.

Nebulized cyclosporine in the rat: assessment of regional lung and extrapulmonary deposition

BACKGROUND

Nebulized cyclosporine (CsA) has been shown to limit lung allograft rejection as well as intramuscular (IM) CsA, with limited blood diffusion. The present study determined the pharmacokinetic parameters of nebulized CsA, by the assessment of regional lung deposition and extrapulmonary diffusion of CsA.

METHODS

CsA was given either by IM injection (10 mg/kg) or by aerosol (at 10 and 25 mg/kg doses); 70 rats were killed at 25 and 50 min, and at 2, 4, 6, 8, 12, 24, or 48 hr after CsA administration. CsA levels were measured in the whole lung, in central and peripheral parts of the lung, in whole blood, kidney, and heart. The areas under the concentration time curves (AUCs) were determined.

RESULTS

In blood, kidney, and heart, CsA levels were significantly higher for IM than for aerosol administrations at 10 and 25 mg/kg doses. In the whole lung, the AUC was greater for the aerosol route at 25 mg/kg doses (588 ng x hr/mg) than for the low-dose (200 ng x hr/mg) or IM administration (200 ng x hr/mg). The central to peripheral index of CsA (ratio of AUC central/peripheral part of the lung) was not significantly different for both aerosol administrations (0.63 and 0.69, respectively) and for the IM route (0.81).

CONCLUSIONS

Nebulized CsA allows better pulmonary concentration than IM administration, with equivalent central and peripheral deposition whatever the mode of administration, and results in lower levels in blood, kidney, and heart.

Expression of gamma-IFN mRNA in bronchoalveolar lavage fluid correlates with early acute allograft rejection in lung transplant recipients

Various cytokines are upregulated in acute allograft rejection (AR). Local production of Th-1 cytokines is suggested to play a pathogenic role in AR, and Th-2 cytokines in the development of allograft tolerance. The purpose of this study was to correlate the expression of Th-1 [interleukin-2 (IL-2) and gamma-interferon (gamma-IFN)], and Th-2 [interleukin-10 (IL-10)] cytokines in bronchoalveolar lavage (BAL) fluid with AR in lung transplant (LT) recipients. The role of Th-1 dominance expressed as IgG2/IgG1 ratio in BAL in AR was also examined. The mRNA expression for IL-2, gamma-IFN and IL-10 was examined in 64 BAL specimens from 23 LT recipients using reverse transcriptase-polymerase chain reaction (RT-PCR). IgG1 and IgG2 levels were measured in 55 BAL specimens by enzyme-linked immunosorbent assay (ELISA). The expression on mRNA for these cytokines, and the ratio of IgG2/IgG1 was correlated with AR (early AR occurring within 3 months of transplant and late AR occurring after 3 months). Ten patients had 17 episodes of biopsy proven AR. Twelve episodes of AR (6 patients) occurred within the first 3 months of transplantation. In 5 patients, AR was diagnosed 4, 5, 6, 9 and 24 months post-transplantation. Detection of gamma-IFN mRNA correlated significantly with early AR (p < 0.001), whereas it lacked correlation with late AR. Expression of IL-2 and IL-10 mRNA did not correlate with AR. IL-10 was present in most samples irrespective of the presence or absence of AR. The ratio of IgG2/IgG1 was similar in patients with or without AR. Our findings suggest that the detection of gamma-IFN mRNA in BAL by RT-PCR is useful for immune monitoring of early AR in LT recipients. Absence of elevated IgG2/IgG1 ratio, and presence of IL-10 in BAL during AR suggests that Th-1 cytokines may not be the sole mediator of rejection in LT recipients.

The use of combined intravenous pulse methylprednisolone and oral cyclosporin A in the treatment of corneal graft rejection: a preliminary study

PURPOSE

Oral cyclosporin A used in addition to high-dose intravenous pulse methylprednisolone has been shown to have an adjunctive effect in reversing the rejection of liver and renal transplants. The aim of this prospective study was to evaluate the benefits and risks of this combined drug therapy in acute corneal graft rejection.

METHODS

Eleven patients with acute corneal graft rejection received the combined regimen of a single pulse of intravenous methylprednisolone (500 mg) and a low dose of oral cyclosporin A (to maintain a trough blood level of 100-200 micrograms/l).

RESULTS

At a mean follow-up of 16.5 months (range 8-22 months) from the presentation of the graft rejection, reversal of graft rejection was achieved in 10 of 11 cases (90.9%). No recurrence of graft rejection was encountered during the study period. One patient developed a duodenal ulcer, which healed after medical treatment. No other complications were encountered.

CONCLUSIONS

The high efficacy and low risk of the combined regimen demonstrated in this preliminary study call for a larger-scale prospective double-masked study to confirm the value of this treatment protocol.

Effect of cyclosporin A on inflammatory cytokine production by human alveolar macrophages

Cyclosporin A (CsA) is an immunomodulator drug that has been used in the treatment of several types of advanced pulmonary interstitial disease. This beneficial effect occurs mainly in circumstances in which alveolitis due to CD4 lymphocytes is absent, suggesting that CsA acts on other types of cells. The present study was undertaken to determine the effect of CsA on inflammatory cytokine secretion by human alveolar macrophages (AMs). Human AMs were collected by bronchoalveolar lavage from four control subjects and 13 patients with interstitial lung disease. Purified human AMs were incubated with different concentrations of CsA (200, 20 and 2 ng ml-1) in the presence or absence of lipopolysaccharide (LPS). Interleukin-1 beta (IL-1 beta), tumour necrosis factor-alpha (TNF-alpha), IL-6 and IL-8 levels were measured in supernatants using specific enzyme-linked immunosorbent assays. It was found that CsA inhibits basal secretion of TNF-alpha and IL-8 at 20 and 200 ng ml-1. However, none of the different concentrations of CsA modified basal secretion of IL-1 beta nor IL-6. By contrast, a lower concentration of CsA (2 ng ml-1) inhibits LPS-stimulated secretion of all inflammatory cytokines. It is concluded that CsA exerts a modest effect on inflammatory cytokine production by human AMs.

Bronchiolitis obliterans: pathogenesis, prevention, and management

Increasing early success-post lung transplant has been tempered by the long-term development of histologic bronchiolitis obliterans (OB) or of the progressive airway obstruction which is called bronchiolitis obliterans syndrome (BOS). Multiple lines of evidence suggest that OB/BOS is due to an injury directed against the epithelial cells in the airways of the donor lung by the immune system of the recipient. Acute rejection is the strongest risk factor for the subsequent development of this process. Efforts to prevent or minimize acute rejection may reduce the prevalence of OB/BOS. Results of treatment with augmented immunosuppression have been disappointing but the treatment of complicating infections in the allograft can be beneficial. Multicenter studies are needed to assess the efficacy of new immunosuppressive agents in preventing or treating OB/BOS.

Interleukin 6 and interferon-gamma gene expression in lung transplant recipients with refractory acute cellular rejection: implications for monitoring and inhibition by treatment with aerosolized cyclosporine

BACKGROUND

The purpose of this study was to correlate cytokine gene expression from bronchoalveolar lavage (BAL) cells and peripheral blood lymphocytes (PBL) with graft histology in recipients with persistent acute rejection treated with aerosolized cyclosporine (ACsA).

METHODS

We measured mRNA for interleukin (IL) 6, interferon (IFN)-gamma, and IL-10 in recipients (1) without rejection (n=13), (2) with acute rejection that responded to pulsed methylprednisolone (n=7), and (3) with "refractory" acute rejection that failed to respond to conventional immunosuppression (n=17). In the latter group, ACsA was initiated.

RESULTS

BAL cell IL-6 and IFN-gamma were highest in recipients with refractory rejection compared with recipients with steroid-responsive rejection and recipients with no rejection. Improvement in rejection histology occurred in 15 of 17 recipients who were treated with ACsA. IL-6 and IFN-gamma mRNA levels from BAL cells decreased during treatment with ACsA (median IL-6:actin ratio: before treatment, 0.40 vs. after treatment, 0.003, P=0.001; IFN-gamma:actin ratio: before treatment, 0.32 vs. after treatment, 0.04, P=0.001). PBL IL-6 and IFN-gamma mRNA expression also decreased during ACsA treatment after 180 days. Expression of IL-10 mRNA from BAL and PBL did not change during ACsA treatment (0.0 vs. 0.03 and 0.0 vs. 0.02, respectively).

CONCLUSIONS

IL-6 and IFN-gamma mRNA expression from BAL cells was highest in those recipients with refractory histologic acute rejection. ACsA was associated with decreased IFN-gamma and IL-6 gene expression in BAL cells and PBL.

Review of immunosuppression for lung transplantation. Novel drugs, new uses for conventional immunosuppressants, and alternative strategies

The history, pharmacokinetics, mechanisms of action, and experimental as well as clinical data on the immunosuppressive potential of the novel drugs tacrolimus (FK506), sirolimus (rapamycin), mycophenolic acid (mycophenolate mofetil), and leflunomide (and its malononitriloamide analogues) are provided. Novel approaches with the following conventional immunosuppressants are outlined: methotrexate, aerosolized immunosuppression and the implementation of steroid taper. Total lymphoid irradiation and photopheresis for treatment of recurrent rejection are also discussed.

Treatment of refractory acute allograft rejection with aerosolized cyclosporine in lung transplant recipients

Lung transplant recipients who have persistent acute cellular rejection are at increased risk for the development of chronic rejection, the leading cause of reduced long-term survival. This study evaluated the use of aerosolized cyclosporine as rescue therapy for unremitting acute rejection. Between June 1993 and March 1996, 18 patients with rejection that failed to resolve after therapy with pulse steroids and antilymphocyte globulin were enrolled in the study. Aerosolized cyclosporine A (300 mg) treatment was initiated for 10 consecutive days followed by a maintenance regimen of 3 days per week. Efficacy was assessed by graft histologic and pulmonary function testing. With the use of linear regression, results in these patients were compared with those in 23 control patients, matched for histologic acute rejection, who had continued to receive conventional rescue therapy. Two patients were unable to tolerate the treatments and were withdrawn from the study. Significant improvement in histologic rejection occurred in 14 of the remaining 16 patients after a mean of 37 days of aerosolized cyclosporine therapy. Measures of forced vital capacity and forced expiratory volume in 1 second (change in percent predicted/100 days plus or minus the standard error) increased over time in the treated patients whereas the condition of control patients declined despite repeated attempts at conventional rescue (forced vital capacity, aerosolized cyclosporine group, 4.6 +/- 2.9 vs control group -8.1 +/- 1.9, p = 0.001; forced expiratory volume in 1 second, aerosolized cyclosporine group, 2.1 +/- 4.4 vs control group -9.8 +/- 2.6, p = 0.043). Renal and hepatic toxicity during cyclosporine therapy was not observed. The incidence of acute histologic rejection (> or = A2) decreased from 2.49 +/- 0.68 episodes/100 days before aerosolized cyclosporine therapy to 0.72 +/- 0.3 episodes/100 days (p < 0.05). In summary, aerosolized cyclosporine is a safe and effective therapy for acute rejection that has failed to improve with conventional treatment.