Serum interleukin-2 levels in lung transplant recipients: correlation with findings on transbronchial biopsy

Serum interleukin-2 (IL-2) levels were examined in the serum of 17 lung transplant recipients who underwent transbronchial biopsies to diagnose reasons for allograft dysfunction. Over 60 transbronchial biopsies were performed in these 17 patients in a 22-month observation period. Mean serum IL-2 levels were significantly elevated in patients experiencing allograft rejection (p less than 0.01), cytomegalovirus pneumonia (p less than 0.0006), and bacterial/fungal pneumonia (p less than 0.01), when compared with those with normal or nondiagnostic findings on transbronchial biopsies. Serum IL-2 levels were not extraordinarily elevated as seen in other types of allograft rejection and did not differentiate between infection and rejection. In addition, overlapping values were seen in the patient groups tested. Despite these limitations, elevated serum IL-2 levels in lung allograft recipients may provide supplemental information helpful in deciding when to perform transbronchial biopsies.