Serum interleukin-2 receptor levels measured by enzyme immunoassay in heart and kidney transplanted patients.

IL-2R serum concentrations were assayed by a sandwich enzyme immunoassay method in order to ascertain if the measurement of the soluble form of IL-2R can be considered a useful marker of allograft rejection in heart and kidney transplanted patients. Serum IL-2R levels increased significantly compared to pre-operated values (1129 +/- 215 U/ml vs. 592 +/- 209 U/ml, p less than 0.01) in six heart-transplanted patients during acute rejection crises documented by clinical findings and endomyocardial biopsy, and returned to baseline levels after successful treatment (544 +/- 395 U/ml vs. 1129 +/- 215 U/ml, p less than 0.01). Moreover, we observed that severe bacterial (n = 5) or viral (n = 2) infections were also accompanied by a significant increase of IL-2R serum levels in heart-transplanted patients (1076 +/- 263 U/ml vs. 486 +/- 146 U/ml, p less than 0.01 in bacterial, and 1290 +/- 368 U/ml vs. 370 +/- 85 U/ml in viral infections). In the six patients with renal transplant, the mean pre-operative IL-2R level was also elevated (1507 +/- 203 U/ml). A 1.5-4 fold increase of IL-2R levels has been observed at the beginning of both acute rejection and clinically evident infection. Our data show that the serum concentration of IL-2R is increased in heart and kidney transplanted patients during allograft rejection crisis. However, the information gained with this assay must be cautiously interpreted because an increase of IL-2R concentrations can also indicate bacterial or viral infections.(ABSTRACT TRUNCATED AT 250 WORDS)