Role of interleukin 2 receptors in immunologic monitoring following cardiac transplantation.

Two-color flow cytometry was used to measure lymphocyte activation antigens, IL-2 receptor (IL-2R), and HLA-DR, on T helper/inducer and cytotoxic/suppressor subsets in the peripheral blood of cardiac transplant patients. Data including 213 cardiac biopsies to determine rejection were obtained on 24 consecutive recipients receiving cyclosporine and prednisone, who survived greater than 5 weeks. The results showed a correlation between the presence of CD4(T4)-IL-2R and rejections or infection occurring within the first 5 weeks posttransplantation. Sensitivity was 79% (73% for rejection only) specificity 97%, P less than .001 by Fisher's exact test. The number of T4-IL-2R cells peaked at 213 cells/microliter with a mean lead time of approximately 3 days prior to positive biopsy (n = 8). After 5 weeks posttransplantation, the sensitivity decreased to 35% (25% rejection only). This decrease may be due to the lack of samples immediately prior to biopsy in patients after 5 weeks posttransplantation. CD8(T8)-IL-2R, T8-DR, T4-DR levels did not correlate with rejections. The results suggest that T4-IL-2R cells that escape cyclosporine inhibition are highly correlated with rejection and enumeration may contribute to increased utility of immune monitoring in these patients.