Benefits of posttransplantation monitoring of interleukin 6 in lung transplantation.

To determine the predictive diagnostic value of interleukin 6 (IL-6) monitoring in lung and heart-lung transplants, we measured posttransplantation serum IL-6 levels in 17 adult lung or heart-lung transplant recipients. Posttransplantation IL-6 elevation patterns were classified into 4 groups: serum IL-6 level remained negative throughout the monitoring period (group 1; n = 1; 6%); several sharp spikes with normal baseline (group 2; n = 9; 53%); persistently high level of serum IL-6 (group 3; n = 3; 18%); and several sharp spikes of serum IL-6 elevation with abnormally high baseline (group 4; n = 4; 24%). One patient without an elevation of IL-6 (group 1) did not experience any episodes of rejection or infection. Nine patients in group 2 had 19 IL-6 spikes, 13 of which were associated with histopathologically or clinically diagnosed rejection, 3 with acute bronchitis, and 1 with diffuse alveolar damage. Three patients in group 3 had persistent infections including cytomegalovirus infection, toxic megacolon, and repeated bacterial infection during the monitoring period, and 4 in group 4 died within 3 months after transplantation. From this study it appears that a spiked elevation of IL-6 could have a predictive value in diagnosing rejection, and persistently high levels of IL-6 indicate the presence of infection. Thus, IL-6 monitoring is beneficial for lung transplant recipients.