The combi-effect--reduced rejection of the heart by combined transplantation with the lung or spleen

Risk of recipient age on 1-year mortality after simultaneous heart-lung transplantation

BACKGROUND

Heart-lung transplantation (HLTx) is relatively uncommon, and there is a paucity of literature to suggest an age at which older recipients may be exposed to excess risk for mortality. This analysis aimed to identify a threshold of age that predicts adverse outcomes after HLTx.

METHODS

The United Network of Organ Sharing registry was used to identify adult patients undergoing HLTx from 2005 to 2021. The primary outcome was 1-year mortality. Threshold regression was used to identify the threshold at which age impacts 1-year mortality. Kaplan-Meier analysis was used to model survival, and Cox proportional hazards modeling was used for risk-adjustment.

RESULTS

We identified 453 patients undergoing HLTx. Threshold analysis identified that the risk for 1-year mortality was significantly elevated beyond an age of 58 years, and 47 (10.38%) patients were older than this threshold. On Kaplan-Meier analysis, 1-year survival was significantly lower in patients > 58 years compared to younger recipients (64.7% vs. 82.0%, p = .007). After risk adjustment, the hazard ratio for 1-year mortality in recipients older than 58 years was 2.27 (95% confidence interval [1.21-4.28], p = .011).

CONCLUSION

A threshold for recipient age of 58 years of age may avoid excess 1-year mortality after HLTx. However, patients older than this threshold demonstrate acceptable early and midterm survival, and the majority survive to 1 year. Advanced age should be considered in patient selection for HLTx, but may not be a contraindication for candidacy particularly in the absence of other risk factors.

Combined Heart Lung Transplantation: An Updated Review of the Current Literature

Heart lung transplantation is a viable treatment option for patients with many end-stage heart and lung pathologies. However, given the complex nature of the procedure, it is imperative that patients are selected appropriately, and the clinician is aware of the many unique aspects in management of this population. This review seeks to describe updated organ selection policies, perioperative and postoperative management strategies, monitoring of graft function, and clinical outcomes for patients after combined heart-lung transplantation in the current era.

Respiratory viral infection in obliterative airway disease after orthotopic tracheal transplantation

BACKGROUND

The long-term survival after human lung transplantation is limited by bronchiolitis obliterans syndrome (BOS). Clinically, community-acquired respiratory viral infections have been correlated with an increased incidence of BOS. The goal of this study was to investigate the role of respiratory viral infections in chronic lung allograft rejection using the murine orthotopic tracheal transplantation model.

METHODS

Eighty orthotopic tracheal transplants were performed using BALB/c and C57BL/6 mice. Recipient mice were infected intranasally with Sendai virus (SdV), a murine parainfluenza type I virus. Experiments altering the infectious dose, infection time, harvest time, allogeneic response, and viral response were performed. Tracheal allograft rejection was monitored using percent fibrosis and lamina propria to cartilage ratio measurements. Interferon-gamma ELISPOT analysis against irradiated donor (BALB/c) splenocytes was used as immunologic indicator of alloreactivity after transplantation.

RESULTS

Sendai virus infection revealed a dose-dependent transient suppression of alloreactivity with a decrease in tracheal allograft fibrosis and frequency of alloreactive T cells at 30 days. This immunosuppression was reversed by day 60, leading to increased tracheal allograft fibrosis with a concomitant increase in the frequency of interferon-gamma producing alloreactive T cells. Pretransplant sensitization with donor antigens prevented the initial suppression of alloreactivity due to SdV infection. Furthermore, pretransplant immunization against SdV infection resulted in rapid clearing of the infection and reduced the immunopathology of rejection.

CONCLUSIONS

Respiratory viral infections can cause enhanced tracheal allograft rejection despite the initial phase of transient immunosuppression. Early treatment or vaccination against the respiratory infections may represent a viable intervention to reduce the risk of chronic rejection.

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.

Donor Leukocytes Combined With Delayed Immunosupressive Drug Therapy Prolong Limb Allograft Survival

Donor leukocytes administered at the time of transplantation may prolong organ allograft survival. Delayed administration of calcineurin inhibitors, such as FK506 or cyclosporine, may enhance their efficacy. Herein the effectiveness of this strategy to promote limb transplant survival was investigated in the strong histocompatibility barrier of Brown-Norway donor to Lewis recipients. Donor leukocytes (6 x 10(7) intravenously) were injected on the day of transplantation followed on day 1 to 14 with mycophenolate mofetil (MMF; 15 mg/kg/d) and prednisone, (0.5 mg/kg/d) which were then tapered by 20% each week and stopped at week 7. Administration of of FK506 (2 mg/kg/d) was started on day 4 and continued for 8 weeks, then tapered for 4 weeks to a maintenance dose of 0.8 mg/kg/d, which was continued for 12 weeks (group A; n = 8). A control group (n = 8) underwent identical treatment save for donor leukocyte injection but rather commencement of FK506 on day 1. Rejection was common during FK506 tapering in both groups. However group A showed a significantly later onset, a shorter period for reversal of the first rejection, and a significantly lower dosage of FK506 at the time of rejection. After the completion of immunosuppression, rejection occurred significantly later in group A than the control group with one animal surviving without immunosuppression on day 344. This is the first trial of a donor leukocyte injection combined with delayed FK506 administration in limb transplantation, which suggested that it could produce a modest but significant improvement in outcome.

Donor leukocytes combine with immunosuppressive drug therapy to prolong limb allograft survival

Donor leukocytes administered at the time of transplantation may prolong organ allograft survival. This study examined the effectiveness of donor leukocyte injection combined with immunosuppression for limb transplantation across the strong histocompatibility barrier of a Brown Norway donor to a Lewis recipient. Eight animals received 6 x 10(7) donor leukocytes injected on the day of transplantation. From day 1, FK506 (2 mg/kg/d), mycophenolate mofetil (MMF) (15 mg/kg/d), and prednisone (0.5 mg/kg/d) were administered for 2 weeks. After week 2, prednisone and MMF were both tapered by 20% of the initial dosage per week. After week 7, the animals received only FK506 (2 mg/kg/d). From week 8, FK506 was tapered to the maintenance dose of 0.8 mg/kg/d at week 10 and was stopped on week 24. A control group of 8 animals underwent identical treatment except that the leukocyte injection was omitted. Rejection was observed in both groups during FK506 monotherapy; however, the onset of early rejection episodes was significantly later, the period for reversal of the first rejection was significantly shorter, and the dosage of FK506 at the time of rejection was significantly lower among leukocyte-treated recipients. After completion of immunosuppression, survival was modestly prolonged in the leukocyte-treated group. One animal is surviving without immunosuppression on day 234. This trial of donor leukocyte injection combined with immunosuppression in limb transplantation showed a modest, but significant, improvement in outcome.

Tolerogenic protocols for intestinal transplantation

The intestine has long been considered as a "forbidden" organ to transplant [Ann. Surg. 216 (1992) 223-33]. This is due to the particularly challenging nature of the immunological conflict that an intestinal graft may cause: a particularly vigorous rejection response, in addition to the capacity to mount a graft-versus-host disease (GVHD) [Transplantation 37 (1984) 429]. Currently, the short-term success of intestinal transplantation (Itx) depends upon the chronic delivery of profound immunosuppression but this causes infection, malignancies--in particular posttransplant lymphoproliferative disorder (PTLD)--and direct drug toxicity. For these reasons, the results of Itx remain inferior to those of other solid organ transplants in the middle and in the long term (Intestinal Transplant Registry: www.small-bowel-transplant.org). Improved results and wider application of Itx requires the development of protocols that would facilitate acceptance of the new intestine thereby allowing to reduce the need for immunosuppression with its attending complications. Relevant experimental data and the recent evolution in the clinical strategies used to promote acceptance of intestinal grafts are reviewed.

Posttransplant administration of donor leukocytes induces long-term acceptance of kidney or liver transplants by an activation-associated immune mechanism

Donor leukocytes play a dual role in rejection and acceptance of transplanted organs. They provide the major stimulus for rejection, and their removal from the transplanted organ prolongs its survival. Paradoxically, administration of donor leukocytes also prolongs allograft survival provided that they are administered 1 wk or more before transplantation. Here we show that administration of donor leukocytes immediately after transplantation induced long-term acceptance of completely MHC-mismatched rat kidney or liver transplants. The majority of long-term recipients of kidney transplants were tolerant of donor-strain skin grafts. Acceptance was associated with early activation of recipient T cells in the spleen, demonstrated by a rapid increase in IL-2 and IFN-gamma at that site followed by an early diffuse infiltrate of activated T cells and apoptosis within the tolerant grafts. In contrast, IL-2 and IFN-gamma mRNA were not increased in the spleens of rejecting animals, and the diffuse infiltrate of activated T cells appeared later but resulted in rapid graft destruction. These results define a mechanism of allograft acceptance induced by donor leukocytes that is associated with activation-induced cell death of recipient T cells. They demonstrate for the first time that posttransplant administration of donor leukocytes leads to organ allograft tolerance across a complete MHC class I plus class II barrier, a finding with direct clinical application.

An overview of combined heart and kidney transplantation

This review describes to date the experience with combined heart-kidney transplant (HNTx) from a single donor. HNTxs are very uncommon relative to single-organ transplants of the heart and kidney, as well as combined kidney-pancreas and combined kidney-liver transplants. Two groups of patients seem to be candidates for HNTx: 1) those with end-stage heart disease and fixed (nonreversible) renal disease, and 2) those with end-stage renal disease and severe cardiac disease unamenable to other treatment. In both groups, significant disease should be limited to the heart and kidney. Reports to date generally suggest decreased cardiac rejection in HNTx relative to heart-only transplants. Renal rejection in HNTx seems markedly reduced relative to kidney-only transplants. Simultaneous rejection of both organs is very uncommon, and, therefore, surveillance of both organs is necessary. Short-term patient survival seems to be acceptable in HNTx. Long-term patient and graft survival remains unknown, and further multi-center reports are needed.

Anti-CD4 therapy in combined heart-kidney, heart-liver, and heart-small bowel allotransplants in high-responder rats

BACKGROUND

In these experiments, we studied the role of anti-CD4 (Ox38) monoclonal antibody in the induction of allograft unresponsiveness in high-responder Lewis rats in the single liver, kidney, small bowel, and heart versus the combined heart-kidney, heart-liver, and heart-small bowel transplantation models.

METHODS

ACI heart, kidney, liver, and small bowel allografts were transplanted into untreated and anti-CD4 treated Lewis rats. In selected animals bearing long-surviving ACI liver or kidney allografts for over 3 months, donor-matched second heart or third-party (Brown Norway) heart allografts were transplanted. Simultaneously, heart-liver, heart-kidney, and heart-small bowel transplants were performed on the day of operation. Rejected allografts were verified by autopsy and pathology.

RESULTS

ACI liver allografts were permanently accepted by Lewis recipients treated with either regular-dose (5 mg/kg for 4 days) or low-dose (5 mg/kg for 2 days) of anti-CD4 monoclonal antibody. Pretransplant anti-CD4 therapy (5 mg/kg for 4 days but not 5 mg/kg for 2 days) resulted in a long-term survival of kidney allografts (mean survival time [MST] > 100.0 days, n=5). Pretransplant anti-CD4 treatment (5 mg/kg for 4 days) could not induce tolerance when single ACI hearts were transplanted; however, long-term survival of ACI heart allografts could be induced when heart transplants were combined with liver (n=7) or kidney (n=8) transplants. The survival of both ACI heart allografts (MST=25.0 days, n=4) and small bowel allografts (MST=28.0 days, n=4) was also prolonged when simultaneous heart and small bowel transplantation was performed in anti-CD4-treated recipients. The second ACI heart allograft was permanently accepted by tolerant Lewis recipients of ACI liver or kidney allografts induced by anti-CD4 treatment, and third-party heart grafts were acutely rejected without affecting survival of the primary allografts.

CONCLUSION

Our current results show that: (1) there is a vigorous rejection of heart > or = small bowel > kidney > liver in high-responder Lewis rats after pretransplant anti-CD4 therapy; and (2) simultaneous or metachronous combined liver-heart and kidney-heart transplants may protect heart allografts from rejection.

What is the optimal approach for the end-stage diabetic nephropathy patient considering simultaneous pancreas-kidney transplantation?

This case-based discussion regards two very different patients with end-stage diabetic nephropathy (ESDN) who are considering transplantation. What is the best approach for each individual: pancreas-kidney transplant or kidney transplant alone? Suppose a live kidney donor is available? What are the risks and benefits of each approach? In the candidate evaluation process, medical issues, such as uncorrectable coronary artery disease, are investigated and may preclude transplantation altogether or dictate the optimal approach. Similarly, a careful psychosocial profile is important to tailor the approach to the patient. The multidisciplinary transplant team has an obligation to provide informed consent, foster realistic expectations, and advise the candidate based on collective expertise. Ultimately, the decision as to the best course-pancreas-kidney, kidney transplant alone, or no transplantation-is the result of a collaborative effort between the patient and the transplant team.

Simultaneous heart and kidney transplantation as treatment for end-stage heart and kidney failure

BACKGROUND

The aim of the present analysis was to define the role of simultaneous heart and kidney transplantation (HNTX) using organs from the same donor by evaluation of clinical strategy and achieved outcome compared with a reference group of concurrently single heart transplant (HTX) and kidney transplant (NTX) recipients. Compared with other organ combinations (pancreas-kidney, heart-lung), HNTX has been performed infrequently and is reported mainly as case records in the literature. Because of expansion of recipient selection criteria for HTX and NTX, the number of patients requiring simultaneous replacement of both organs is increasing.

METHODS

Six HNTX recipients, three of them suffering from long-standing type I diabetes, received transplants between September 1990 and March 1996 and were analyzed in terms of clinical and immunological demographics and outcome. They were compared with 379 HTX and 769 NTX recipients operated upon within this period.

RESULTS

Survival for HNTX is 100% with a mean follow-up of 32.7+/-21.1 months. Cold ischemic time of the kidney was significantly shorter for HNTX than for NTX (6.5+/-1.0 hr vs. 22.1+/-6.8 hr, P<0.005). Although HNTX patients received HLA-unmatched grafts, no rejection of the kidney has been observed to date. There was no difference for rejection of the heart in HNTX compared to HTX recipients.

CONCLUSIONS

Satisfying results are obtained by HNTX and justify the use of two organs for one recipient. The favorable immunological behavior of the kidney despite use of HLA-unmatched grafts is most probably explained by higher immunosuppression and short cold ischemic time, although a combination effect cannot be excluded.

Are heart-lung transplant recipients protected from developing transplant coronary artery disease? A case-matched intracoronary ultrasound study

BACKGROUND

Accelerated coronary artery disease is a major cause of mortality in heart transplant recipients; however, it does not appear to play a major role in the clinical outcome of heart-lung transplant recipients. The purpose of this study was to determine whether the incidence and severity of transplant coronary artery disease as detected by intracoronary ultrasound in heart-lung transplant recipients are less than those encountered in heart transplant recipients.

METHODS AND RESULTS

We studied the left anterior descending coronary artery with the use of intracoronary ultrasound imaging in 22 heart-lung transplant recipients at the time of their routine annual coronary angiogram. Twenty-two heart transplant recipients were case matched for number of years after transplant at ultrasound study, recipient age, donor age, and diagnosis of nonischemic cardiomyopathy. Mean intimal area, intimal index, Stanford class, and incidence of at least moderate disease (Stanford class > or = 3) were measured and calculated in each group and then compared between the two groups. Mean intimal area (1.6 +/- 2.5 versus 3.8 +/- 2.8 mm2), mean intimal index (0.07 +/- 0.10 versus 0.22 +/- 0.14), mean Stanford class (1.7 +/- 1.0 versus 2.7 +/- 1.2), and incidence of Stanford class > or = 3 (14% versus 45%) were significantly lower in the heart-lung transplant recipient group.

CONCLUSIONS

The incidence and severity of transplant coronary artery disease are much less in patients receiving heart-lung transplants than in those receiving heart transplants alone.

Enhancement of cytomegalovirus infection and acute rejection after allogeneic lung transplantation in the rat

A possible mechanism of the induction of lung transplant rejection by cytomegalovirus (CMV) infection is the inflammatory upregulation of adhesion ligand molecules on transplant endothelia by the viral infection leading to leukocyte activation. To study this question a rat model of rat cytomegalovirus (RCMV) infection and acute lung transplant rejection was established to study: (1) the influence of RCMV infection on the course of rejection, (2) the influence of rejection on the course of RCMV infection, and (3) the influence of RCMV on adhesion molecule expression and leukocyte infiltration. For this Lew (RT1l) rats received either syngenic (n=25) or allogeneic (BN, RT1n; n=38) left lateral lung transplants. Postoperatively, CsA 25mg/kg was given on days 1-3 and triple drug (CsA, Aza, Pred) immunosuppression was given from days 4-10 to induce systemic RCMV infection and acute rejection developed from postoperative day (POD) 15-25 in allogeneic transplants. In RCMV-positive animals the rejection grade was gradually increased at POD 15 and 18. Furthermore, after allogeneic transplantation an enhanced viral infection of the lung transplant as early as POD 11 was found and increased salivary gland PFU titers on days 20 and 25. In the absence of rejection infiltration a maximal induction of ICAM-1 adhesion molecules was found on lung endothelia in RCMV+ allogeneic animals as compared with noninfected controls. This induction was found to lesser degree for VCAM-1 and MHC class II adhesion ligand molecules. This was accompanied by a significantly increased CD11a+ and CD49d+ leukocyte infiltration into the alveolar interstitium on day 11 and 15 in infected transplants. The results show an enhancement of RCMV infection after allogeneic lung transplantation leading to endothelial activation and recruitment of CD11a/CD49d+ leukocytes. This mechanism may strongly influence transplant inflammation and the long-term course of lung transplant rejection.

Tissue-specific effects of anti-CD4 therapy in induction of allograft unresponsiveness in high and low responder rats

In these experiments, we studied the role of anti-CD4 (Ox38) monoclonal antibody in the prevention of heart and/or kidney allograft rejection in low (ACI) and high (Lewis) responder rats. In low responder ACI rats, donor-specific tolerance for heart and kidney allografts (individually or in combination) was achieved by pretransplant anti-CD4 therapy. In high responder Lewis rats, anti-CD4 therapy alone (or combined with anti-CD8 (Ox8), thymectomy or total lymphoid irradiation) did not prevent first-set rejection of heart allografts. This difference was correlated with a more profound and longer lasting CD4+ cell depletion in the low responder strain. Anti-CD4 treatment, however, produced tolerance of kidney transplants in high responder rats. Additionally, anti-CD4 treatment induced tolerance to heart (as well as kidney) allografts in Lewis recipients of combined kidney and heart allografts from ACI. The effects of anti-CD4 treatment thus depend upon the recipient responder status as well as the organs transplanted and the order of transplantation.