Modern immunosuppression strategies in lung transplantation:

Management of the patient undergoing lung transplantation: an intensive care perspective

The postoperative management of a patient undergoing lung transplantation involves many components of care. These components include ventilatory and hemodynamic management, immunosuppression, wound care, rehabilitation, infection control and treatment, and early detection of rejection.

Emerging drugs in lung transplantation

The balance between immunosuppression to ensure graft tolerance while preventing emergence of infectious complications is key in lung transplantation. Although opportunistic infection may appear to be the most important of these complications, malignancies and severe drug toxicities significantly affect the short- and long-term outcomes of the patients. The present practice is combination therapy using drugs with complementary immunosuppressive action, to achieve synergistic immunosuppression with the lowest possible toxicity. Components of immunosuppression include induction and maintenance regimens. Primary graft failure remains an important cause of mortality and morbidity in the immediate post-transplant period. Acute rejection is a common complication after lung transplant, but responds well to augmented immunosuppression and immunomodulation. Chronic rejection still is the major cause of mortality in patients who survive the initial year post-transplantation. Several new drugs have shown promise in decreasing the rate of loss of graft function. This review discusses the current and emerging therapeutic regimens.

Azathioprine withdrawal in stable lung and heart/lung recipients receiving cyclosporine-based immunosuppression

BACKGROUND

Chronic rejection is the leading cause of graft failure after (heart-) lung transplantation. Therefore, many centers maintain a triple immunosuppressive cyclosporine-based regimen including azathioprine (AZA) during the long-term course after lung transplantation. However, an increased risk of malignancies has been attributed to prolonged immunosuppression, and there is evidence that less intensive immunosuppressive regimens are feasible in the long-term course after other solid organ transplantation. Therefore, we investigated the effects of AZA withdrawal in stable lung transplant recipients.

METHODS

A prospective study was performed to assess the effects of AZA withdrawal in patients who received a lung transplant more than 4 years ago with stable graft function defined by absence of rejection episodes for at least 2 years and no evidence of bronchiolitis obliterans.

RESULTS

A total of 24 patients qualified for the study and 7 discontinued AZA. Despite the small number of patients, termination of the study became necessary after 12 months because significantly more grafts showed deteriorating function after withdrawing AZA (4 of 7) compared to recipients continuing a triple therapy (1 of 17; P<0.05). In recipients with deteriorating graft function conventional treatment with high-dose corticosteroids and reinstitution of AZA failed to stop the development of obliterative bronchiolitis.

CONCLUSIONS

Our data reinforce the importance of a potent immunosuppressive regimen for the maintenance of stable graft function after lung transplantation.

Obliterative bronchiolitis after lung transplantation

Despite marked improvements in early survival, long-term outcome after lung transplantation is still threatened by obliterative bronchiolitis (OB). Thought to be a manifestation of chronic allograft rejection, OB affects up to 65% of patients at 5 years after surgery and produces a relentless airflow obstruction. Early and late acute rejection are the primary risk factors for OB, but cytomegalovirus infection and airway ischemia may also play a role. In most patients, OB responds poorly to augmented immunosuppression and eventually leads to infectious complications and terminal respiratory failure. Because early diagnosis is associated with better prognosis, every effort should be made to detect OB in a preclinical stage. This may be best achieved by combining several techniques, such as surveillance transbronchial biopsy and bronchoalveolar lavage, measurements of ventilation distribution and exhaled nitric oxide, and expiratory computed tomography.