Post-Transplant Lung Issues

Long-Term Follow-Up

Post-Transplant Lung Issues

Q: Are lung problems common after a transplant?


It is estimated that 30 percent to 60 percent of all hematopoietic stem cell transplant (HSCT) patients develop some type of post-transplant lung problem. These can be infections, such as aspergillus or cytomegalovirus (CMV), or non-infectious problems such as bronchiolitis obliterans syndrome (BOS) and bronchiolitis obliterans organizing pneumonia (BOOP).

For further information, please refer to:
Late onset lung problems
Late effects


Q: What causes lung problems after a transplant?


Bronchiolitis obliterans syndrome (BOS) and bronchiolitis obliterans organizing pneumonia (BOOP) are the most common noninfectious lung problems occurring in allogeneic transplant patients. Currently, BO is classified by the National Institutes of Health as a form of graft-vs.-host disease (GVHD) in the lung. Patients are generally at risk for BO if they have GVHD at other sites, are older, had poor lung function before transplant, and had respiratory viral infections. BOOP is seen in association with GVHD, but can occur without active GVHD. Currently, the cause of BOOP is unknown. However, we believe this is also an immune mediated problem that results in inflammation in the lungs. Infectious lung problems generally occur in patients taking immunosuppressive therapy for GVHD.

For further information, please refer to:

Risk factors
Pre-transplant lung problems



Q: What is the difference between bronchiolitis obliterans syndrome (BOS) and bronchiolitis obliterans organizing pneumonia (BOOP)?


BOS is generally a disease of the small airways, where the small airways become narrower presumably due to GVHD, to the point that airflow is limited through the airways. On lung function testing, this appears as an obstructive pattern. When detected, BOS is usually severe and generally irreversible. The goal of therapy with immunosuppression is to prevent progression. Unfortunately, BOS is often "silent" and clinically unnoticed until it is severe. BOS is generally not detectable using standard chest X-ray or CT, but can be detected using a high resolution CT scan. Respiratory infections can also cause airflow obstruction, so patients generally need a bronchoscopy to make sure an infection is not present before initiation of therapy. Therefore, our efforts here have focused on how to identify patients earlier, so treatment may be started to stop the progression of BOS before it becomes severe. BOOP is an inflammatory disease that involves the small airways and the alveoli, the gas exchanging units in the lungs. Most commonly, this results in a restrictive pattern on lung function testing, which means that the lungs cannot expand well. BOOP is detectable using a CT scan or chest X-ray. However, because it looks like pneumonia, additional studies such as bronchoscopy and lung biopsy are usually necessary to confirm the diagnosis. BOOP differs from BOS in that it is very responsive to immunosuppressive therapy. Most BOOP cases are completely reversible, although a small percentage of the population will have steroid resistant or dependent BOOP.

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Q: What can I do to avoid lung problems after a transplant?


Research has shown that patients can develop significant lung function impairment before they begin to notice symptoms. For this reason, it is very important that even patients who don't appear to have a problem be evaluated by their health-care provider. These lung problems tend to occur within the first two years after transplant. This is why the latest recommendations from the National Institutes of Health suggest that lung function is followed closely during the first two years after transplant. Pulmonary function tests should be obtained every three months during the first year, then every six months during the second year, then yearly thereafter. Each of these pulmonary function tests should be compared to each other, as well as the pretransplant pulmonary function test, to determine if there has been a significant change. Patients who have been prescribed medication to prevent infections, especially while on immunosuppressive therapy, should consult their health-care provider before making any changes regarding their medications.