Induction therapy in lung transplantation: a prospective, controlled clinical trial comparing OKT3, anti-thymocyte globulin, and daclizumab

Are heart-lung transplant recipients protected from developing bronchiolitis obliterans syndrome?

BACKGROUND

Heart-lung transplant recipients, when compared with heart transplant recipients, are relatively spared from allograft coronary artery disease. This study was undertaken to investigate whether heart-lung transplant recipients are also spared from experiencing bronchiolitis obliterans syndrome (BOS) when compared with double-lung transplant recipients. In addition, the risk factors for developing BOS after lung transplantation were analyzed.

METHODS

Heart-lung and bilateral sequential double-lung transplant recipients were reviewed retrospectively from 1990 to 2000 using the Stanford Transplant Database. The heart-lung transplant group consisted of 77 heart-lung transplant recipients and the double-lung transplant group consisted of 51 double-lung transplant recipients. The rates of BOS, survival, acute rejection, and cytomegalovirus infection at 1, 3, and 5 years were measured.

RESULTS

There were no significant differences in patient demographics between the two groups. Rates of survival and acute rejection were similar in the two transplant groups. The incidence of cytomegalovirus infection was significantly higher in heart-lung transplant recipients. Freedom from BOS was similar in the two transplant groups. Risk factors for the development of BOS in the heart-lung and double-lung transplant recipients included male donor, younger recipient age, a diagnosis other than cystic fibrosis, nonuse of cardiopulmonary bypass, and the use of OKT3 induction therapy.

CONCLUSIONS

Heart-lung transplant recipients exhibit BOS at a rate similar to double-lung transplant recipients. The immunoprotective effect the lung allograft presumably provides the heart is not reciprocated by the heart in preventing the development of BOS.

A comparison of basiliximab and anti-thymocyte globulin as induction agents after lung transplantation

BACKGROUND

Interleukin-2 receptor antagonists have supplanted polyclonal antibody preparations as the most frequently used induction agents after lung transplantation, but the relative efficacy of these agents has not been firmly established.

METHODS

We retrospectively analyzed the efficacy of basiliximab compared with antithymocyte globulin among 157 adult lung transplant recipients at our center.

RESULTS

At 3, 6, and 12 months after transplantation, the median cumulative acute rejection A scores for the basiliximab group (2, 2, and 3, respectively) were significantly higher than those for the anti-thymocyte globulin group (1, 1, and 2, respectively; p = 0.003, 0.004, and 0.033, respectively). In addition, basiliximab recipients were more likely to develop acute rejection grade > or = A2 than anti-thymocyte globulin recipients; in fact, 60% of basiliximab recipients compared with 38% of anti-thymocyte globulin recipients developed their first episode of acute rejection grade > or = A2 in the first 100 days after transplantation (log-rank p = 0.04). Furthermore, basiliximab recipients were more likely to develop bronchiolitis obliterans syndrome than anti-thymocyte globulin recipients (log-rank p = 0.036). Two years after transplantation, 36% of basiliximab recipients and 26% of anti-thymocyte globulin recipients developed bronchiolitis obliterans syndrome. However, there were no significant differences in the incidences of cytomegalovirus viremia and pneumonitis between the 2 groups (p = 0.86 and 0.89, respectively).

CONCLUSIONS

Induction with anti-thymocyte globulin is associated with a lower burden of acute rejection and bronchiolitis obliterans syndrome compared with basiliximab, without a significant difference in the incidence of cytomegalovirus infections.

Simultaneous Donor Marrow Cell Transplantation With Reduced Intensity Conditioning Prevents Tracheal Allograft Obliteration in a Bronchiolitis Obliterans Murine Model

STUDY OBJECTIVES

Prolonged survival of transplanted kidney or liver allografts has been associated with prolonged chimerism resulting from donor-origin leukocytes carried within the allograft parenchyma. The present study, performed in a murine model, examined whether simultaneous administration of donor bone marrow cells after reduced intensity conditioning allows acceptance of heterotopic tracheal allografts and prevents the formation of the airway fibroproliferative lesion, which mimics bronchiolitis obliterans (BO).

METHODS

Allogeneic tracheal allografts from C57BL/6 mice were grafted subcutaneously into BALB/c mice (n = 6) [day 0]. Conditioning consisted of total lymphoid irradiation (200 cGy) at day - 1, donor marrow cells (3 x 10(7)) administered IV on day 0, intraperitoneal cyclophosphamide (200 mg/kg) on day 1 to eliminate alloreactive marrow cells, followed by a repeated dose of donor marrow cells on day 2. Control groups consisted of one group (n = 4) that underwent similar conditioning without donor marrow cells, and another group (n = 4) that received syngeneic BALB/c marrow cells. None of these groups were administered maintenance immunosuppression. Grafts were harvested and histopathology findings were evaluated semiquantitatively at day 28, day 55, and day 95.

RESULTS

Tracheal allografts from donor marrow cell recipients still maintained a patent airway with intact airway epithelium at 95 days after transplant. However, grafts from control animals not receiving donor marrow cells or mice administered syngeneic marrow cells had lumen obliteration by 28 days after transplant. Chimerism in animals receiving allogeneic bone marrow was confirmed. Graft vs host disease did not develop in animals receiving allogeneic marrow cells.

CONCLUSIONS

Further investigation may verify this approach to be applicable for the prevention of posttransplantation BO.

Allograft Rejection After Lung Transplantation

Lung transplantation has become an accepted therapy for selected patients with advanced lung disease. One of the main limitations to successful lung transplantation is rejection of the transplanted organ. This article discusses the clinical presentation, treatment, and prevention of hyperacute, acute, and chronic rejection in the lung transplant recipient.

Comparative Study of Basiliximab Treatment in Lung Transplantation

OBJECTIVE

This study compared the incidence of acute or chronic rejection and adverse events in lung transplant patients receiving induction basiliximab versus controls not receiving treatment.

MATERIALS AND METHODS

Basiliximab was administered to 15 patients with impaired renal function, advanced age, or high surgical risk, (group I). The mean age was 48.9 years; nine were double-lung and six single-lung grafts. They were compared to 13 lung transplants performed in 2001 (mean age 43.6 years, 11 double lung and two single lung [group II]).

RESULTS

The incidence of acute rejection was 13.3% in group I versus 38.5% in group II (P = .19, OR 4.06), with chronic rejection in 20% and 38.5% of cases, respectively (P = .4, OR 2.5). No significant differences were observed in the incidence of infections or malignancies. Nor were there any direct adverse events due to the administration of the drug. The estimated 2-year survival was 80% for group I and 54% for group II (P = .14).

CONCLUSIONS

Basiliximab has a trend to reduce the rate of acute and chronic rejection in lung transplant recipients, with no increased incidence of infections or malignancies. The 2-year survival for patients treated with basiliximab was better than the control group, despite including high risk transplant patients.

Early outcomes in human lung transplantation with Thymoglobulin or Campath-1H for recipient pretreatment followed by posttransplant tacrolimus near-monotherapy

OBJECTIVES

Acute and chronic rejection remain unresolved problems after lung transplantation, despite heavy multidrug immunosuppression. In turn, the strong immunosuppression has been responsible for mortality and pervasive morbidity. It also has been postulated to interdict potential mechanisms of alloengraftment.

METHODS

In 48 lung recipients we applied 2 therapeutic principles: (1) recipient pretreatment with antilymphoid antibody preparations (Thymoglobulin [SangStat, Fremont, Calif] or Campath [alemtuzumab; manufactured by ILEX Pharmaceuticals, LP, San Antonio, Tex; distributed by Berlex Laboratories, Richmond, Calif]) and (2) minimal posttransplant immunosuppression with tacrolimus monotherapy or near-monotherapy. Our principal analysis was of the events during the critical first 6 posttransplant months of highest immunologic and infectious disease risk. Results were compared with those of 28 historical lung recipients treated with daclizumab induction and triple immunosuppression (tacrolimus-prednisone-azathioprine).

RESULTS

Recipient pretreatment with both antilymphoid preparations allowed the use of postoperative tacrolimus monotherapy with prevention or control of acute rejection. Freedom from rejection was significantly greater with Campath than with Thymoglobulin (P = .03) or daclizumab (P = .05). After lymphoid depletion with Thymoglobulin or Campath, patient and graft survival at 6 months was 90% or greater. Patient and graft survival after 9 to 24 months is 84.2% in the Thymoglobulin cohort, and after 10 to 12 months, it is 90% in the Campath cohort. There has been a subjective improvement in quality of life relative to our historical experience.

CONCLUSION

Our results suggest that improvements in lung transplantation can be accomplished by altering the timing, dosage, and approach to immunosuppression in ways that might allow natural mechanisms of alloengraftment and diminish the magnitude of required maintenance immunosuppression.

Induction Therapy for Pediatric and Adult Heart Transplantation: Comparison Between OKT3 and Daclizumab

BACKGROUND

Induction therapy can reduce morbidity and early mortality in pediatric and adult heart transplant recipients. Monoclonal and polyclonal agents are most widely used; they nonspecifically deplete the T-cell pool and are thus associated with drug-induced side effects. The cytokine release syndrome is one of the most problematic events associated with induction. Daclizumab, a highly humanized, specific interleukin-2 receptor blocker, may be efficacious to the monoclonal agent, OKT3. Due to its specific action and properties, the safety profile of this agent may be superior to OKT3.

METHODS

Forty subjects received daclizumab and their clinical outcomes were compared against a historical group of 40 subjects who received OKT3. Three- and six-month outcome measures included survival, rejection history, steroid burden, and complications.

RESULTS

Mortality was low between the groups with equivalent 6-month survival. No differences in rejection profile or time to the first significant rejection event were detected; no subject had severe acute rejection within the first 180 days. Steroid requirement for maintenance immunosuppression and treatment of rejection was also similar between the groups. Six-month prevalence for complications were significantly different; 55% of OKT3-treated subjects having at least one event compared to 33% of daclizumab-treated subjects (P=0.04). The likelihood of complications occurred within the first month after transplantation.

CONCLUSIONS

Daclizumab induction therapy is as efficacious as OKT3 in the prevention of early acute rejection after heart transplantation among pediatric and adult subjects. Complications related to the induction agent are significantly lower in the humanized product.

Airway cellular response to two different immunosuppressive regimens in lung transplant recipients

A number of new immunosuppressive drugs have become available in transplant medicine. We investigated the effects of two different immunosuppressive protocols on bronchoalveolar lavage fluid cellular characteristics in 34 lung transplant recipients who were treated with anti-thymocyte globulin induction therapy, cyclosporine, azathioprine (AZA), and prednisolone (regimen I), compared with 17 recipients receiving basiliximab induction, tacrolimus, AZA, and prednisolone (regimen II). We performed bronchoalveolar lavages between 15 and 40 d post-transplantation, in stable clinical condition and no acute rejection, cytomegalovirus, and/or respiratory tract infection. The regimen II treatment was associated with a significantly lower percentage lavage fluid lymphocytes than with regimen I. The CD4/CD8 ratio was significantly higher with regimen II than with regimen I: 1.56 (range 0.41-2.16) and 0.33 (0.04-0.95) respectively; p < 0.001, mainly because of a lower percentage CD8(+) cells with regimen II: 25% (12-51) vs. regimen I: 60% (34-77); p < 0.001. The percentage CD4(+) CD25(+) cells appeared lower with regimen II: 21% (10-88) vs. regimen I: 50% (0-87); p = 0.04. Overall survival was similar between the groups, whereas a beneficial trend in freedom of bronchiolitis obliterans syndrome was observed with regimen II. Airway lymphocyte subtypes are affected by the immunosuppressive protocol used. This observation should be taken into account when studying transplant recipients, and may contribute to our understanding of alloreactive airway disease.

Daclizumab induction in solid organ transplantation

Antibody induction therapy is used in solid organ transplantation to prevent rejection in the early postoperative period. It is especially useful in high-risk groups such as retransplants, patients with delayed graft function to delay the initiation of nephrotoxic calcineurin inhibitors (tacrolimus, cyclosporin), highly sensitised recipients and African-American recipients. Historically, antibody induction has been associated with a high incidence of adverse effects and a complicated administration regimen. Daclizumab is a monoclonal antibody that exerts its effect by binding to the alpha subunit (CD25) of the human interleukin (IL)-2 receptor on the surface of activated lymphocytes, thus preventing the binding of IL-2. It is used for induction therapy and is well-tolerated with easy administration. Although originally studied as a five-dose regimen, there is a growing accumulation of data that fewer doses (two or three) are efficacious and less costly for preventing rejection.

Induction therapy after cardiac transplantation: A comparison of anti-thymocyte globulin and daclizumab in the prevention of acute rejection

BACKGROUND

Induction therapy with antibodies decreases and delays early allograft rejection. We compared the safety and efficacy of daclizumab and anti-thymocyte globulin (ATG) with respect to the frequency and severity of acute cardiac allograft rejection in heart transplant recipients.

METHODS

Forty sequential adult patients were retrospectively studied. In the first 20 patients ATG (2.5 mg/kg daily for 3 to 5 days peri-/and post-operatively) was used as induction therapy and, in the remaining 20 patients, daclizumab (1 mg/kg peri-operatively and every 2 weeks thereafter for a total of 5 doses) was used. A standard triple-drug immunosuppression regimen was administered to all patients.

RESULTS

Baseline characteristics and trough levels of cyclosporine in the 2 groups were similar. During the induction period, defined as the first 3 months, 12 acute rejection episodes requiring treatment (ISHLT Grade > or =2) occurred in the ATG group and 9 in the daclizumab group (p > 0.05). However, the number of biopsies with Grade 1 rejection was increased >2-fold in the daclizumab group (n = 35) compared with the ATG group (n = 17; p = 0.04). The total number of biopsies performed within the first 3 months increased by 26% in the daclizumab group. The number and severity of rejection episodes after 3 months was similar in the 2 groups. The overall occurrence of bacterial infections was significantly higher in the ATG group than in the daclizumab group (p = 0.05).

CONCLUSIONS

ATG and daclizumab are equally effective in preventing acute rejections requiring treatment (ISHLT Grade > or =2). Due to the significantly greater frequency of Grade 1 rejections, daclizumab was found to be associated with an increased number of additional biopsies for monitoring rejection status. This implies additional costs to the transplant program, and the long-term implications of the increased number of low-grade rejection episodes remains to be determined.

Lung transplantation: A decade of experience

BACKGROUND

Over the past 3 decades, the field of lung transplantation has been refined. However, many barriers exist that limit long-term success. The purpose of this study was to review a single institution's long-term experience with single and double lung transplantation and to assess the effect of different immunosuppressive therapies on outcomes.

METHODS

Lung transplant recipients, both single and double, were reviewed, retrospectively. Patients were divided into five groups: group I, all lung transplants (n = 127); group II, single lung transplants (n = 73); group III, double lung transplants (n = 54); group IV, OKT3 induction therapy recipients (n = 27); and group V, RATG induction therapy recipients (n = 100). Rates of survival, rejection, bronchiolitis obliterans syndrome (BOS) and infection were analyzed at 1, 3, and 5 years.

RESULTS

There were no significant differences in survival, acute rejection rate, freedom from BOS, nor infection between single and double lung transplant recipients. Induction therapy with RATG (group V) was associated with significantly improved survival and freedom from acute rejection, BOS, and infection when compared to OKT3 induction therapy (group IV).

CONCLUSIONS

An earlier impression that RATG is superior to OKT3 induction therapy has borne true in terms of overall survival and incidence of BOS, acute rejection and infection rates. Lung transplantation, using RATG induction therapy, remains an important modality for end-stage pulmonary disease.

Bronchiolitis Obliterans Syndrome

Post-transplantation bronchiolitis obliterans syndrome (BOS) is a clinicopathological syndrome characterised histologically by obliterative bronchiolitis (OB) and physiologically by airflow limitation. It affects long-term survival with no consistently effective treatment strategy.An updated review of risk factors for OB/BOS, and approaches to prevention and treatment was performed through a systematic review of relevant studies between January 1990 and February 2005. The initial search identified 853 publications, with 56 articles reviewed after exclusions. Early acute rejection is the most significant risk factor, with late rejection (> or =3 months) also significant. Lymphocytic bronchitis/bronchiolitis is relevant, with later onset associated with greater risk. Viral infections are identified as significant risk factors. Human leukocyte antigen matching and OB/BOS development is a weaker association, but is stronger with acute rejection. Recipient and donor characteristics have a minor role. There is limited evidence that altering immunosuppression is effective in reducing the rate of decline in lung function. BOS reflects an allo-immunological injury, possibly triggered by cytomegalovirus and respiratory viral infections, or noninfectious injury. Immunological susceptibility may be reflected by more frequent acute rejection episodes. Preventative and therapeutic modifications in immunosuppression remain important. Identifying markers of immunological susceptibility and, hence, risk stratification requires further research.

Critical care aspects of lung transplantation

Lung transplantation currently is the preferred treatment option for a variety of end-stage pulmonary diseases. Remarkable progress has occurred through refinements in technique and improved understanding of transplant immunology and microbiology. As a result, recipients are surviving longer after their transplant. Despite improvements in short- and intermediate-term survival, long-term success with lung transplantation remains limited by chronic allograft rejection, also known as bronchiolitis obliterans syndrome. Despite its long-term limitations, lung transplantation remains the only hope for many with end-stage pulmonary disease, and during the past 20 years, it has become increasingly accepted and used. As a result, clinicians working in an intensive care unit (ICU) are more likely to be exposed to these patients both in the immediate postoperative period as well as throughout their remaining lives. It is thus important that the ICU team have a working knowledge of the common complications, when these complications are most likely to occur, and how best to treat them when they do arise. The main focus of this review is to address the variety of potential graft and life-threatening problems that may occur in lung transplant recipients. Because the ICU is also the most common setting where a potential donor is identified, donor issues will briefly be addressed.

Comparison of three tacrolimus-based immunosuppressive regimens in lung transplantation

Immunosuppressive therapy for solid organ transplantation has significantly evolved over the past decade. While these therapies have been found to be beneficial in abdominal organ transplantation, the efficacy of these therapies remains unclear in lung transplantation. We retrospectively compared three potent immunosuppressive regimens in our lung transplant population: Group 1 (tacrolimus/azathioprine/prednisone), Group 2 (tacrolimus/azathioprine/prednisone/daclizumab) and Group 3 (tacrolimus/mycophenolate mofetil/prednisone/daclizumab). We compared these three groups with respect to 3-year rates of acute rejection, chronic rejection, infection and survival. A total of 109 patients was followed during the course of this study. There were 32 patients in Group 1, 49 patients in Group 2 and 28 patients in Group 3. Freedom from acute rejection at 1 and 3 years were higher in Group 3 compared with Group 1 (p < 0.05). The overall incidence of infection up to 3 years after transplantation was comparable among all three groups. Freedom from chronic rejection and survival at 1 and 3 years did not differ among the three groups. In conclusion, we determined the safety and efficacy of three potent immunosuppressive regimens in lung transplantation. Addition of daclizumab and MMF to a tacrolimus-based immunosuppressive regimen decreased the incidence of acute rejection episodes without increasing any adverse events in our lung transplantation population.

Acute allograft rejection after lung transplantation: diagnosis and therapy

Acute rejection remains a significant problem after lung transplantation. While it generally is a treatable condition, significant resources and therapies are directed toward its prevention and resolution. Its larger significance undoubtedly rests in its contribution to the pathogenesis of BOS. Significant questions regarding the origins of AR, the role of LBB, alternative histologic appearances of acute allograft injury, and optimal therapy remain. Controversy regarding the utility of surveillance bronchoscopy and preemptive treatment of occult AR persists because of lack of conclusive evidence. Future investigations might resolve these matters and provide more efficacious and less toxic therapies that will hopefully reduce the impact of chronic rejection and improve long-term outcomes.