A study found that cystic fibrosis (CF) patients, especially younger patients, may be at increased risk of acute cellular rejection of transplanted tissues compared to other transplant patients. The study, “Higher Risk of Acute Cellular Rejection in Lung Transplant Recipients with Cystic Fibrosis,” was recently published in the journal Annals of Transplantation.
According to Fiorella Calabrese and colleagues from the University of Padova, Italy, no studies to date have looked into the frequency of acute cellular rejection, the most common form of transplant rejection, in CF patients who underwent a lung transplant.
Researchers compared the records of 44 patients who underwent lung transplants as a CF treatment and 89 patients who received lung transplants for other reasons, and found no difference between the two groups regarding acute cellular rejection events. Patients by group, however, differed in many respects. Those in the CF group were younger and had more pre-transplant infections or bacterial colonization, a lower body mass index (BMI), and fewer co-morbidities.
The team then stratified the patients into age groups, and compared patients with similar levels of cellular rejection. When taking age into account, they observed that CF patients had a higher risk of rejection. Moreover, younger age was a risk factor for rejection in its own right.
The study also looked at how often CF patients receiving lung transplants died of bronchiolitis obliterans syndrome (BOS) — an increase in fibrosis that closes the airways. No difference was found in BOS occurrence between CF patients and other lung transplant patients one year after surgery. CF patients also did not have more severe BOS than other patients. Furthermore, researchers reported no differences in the severity of airway inflammation or in the number of post-transplant viral infections or pneumonia between the two groups.
Interestingly, in spite of the increased frequency of acute cellular rejection in CF patients, more patients in the group receiving transplants for other reasons died in both the first and second year following surgery.
The authors could not present a scientifically sound explanation for their findings, but speculated that enhanced immune activation in CF patients might increase the risk of rejection. Another possibility is that CF patients respond less well to the drug cyclosporine, used to prevent rejection, although similar levels of cyclosporine were reported in the blood of patients in each of the two groups.