Serum & urinary interleukin-2 levels as predictors in acute renal allograft rejection.

BACKGROUND & OBJECTIVES In spite of potent immunosuppression, acute rejection continues to be the single largest cause of graft dysfunction after renal transplantation. Renal allograft biopsy, though invasive, continues to be the reference standard, though certain clinical and biochemical parameters are helpful in assessment of these patients. Acute renal allograft rejection is mediated by T lymphocytes, which express increased number of interleukin-2 receptors (IL-2R). The soluble component of IL-2R in serum and urine may be useful in detecting early graft rejection. This study assesses the possibility of using serum and urinary IL-2R estimation in early prediction and diagnosis of acute renal allograft rejection. METHODS Sequential estimation of serum and urinary IL-2R levels along with serum creatinine values were assessed in 23 live related renal allograft recipients. The age of renal allograft recipients was 35+/-8.3 yr, with male:female ratio of 22:1. Samples were collected pre-transplant (day 0) and post-transplant upto 30 days and the patients were followed for 6 months after transplantation. Eight recipients experienced graft dysfunction and graft biopsies were evaluated. RESULTS Serum and urinary IL-2R patterns along with serum creatinine levels were correlated with the occurrence of graft rejection on histology. Eight recipients experienced acute graft rejection after transplantation and 15 had stable graft function. Serum IL-2R levels at various periods after transplantation were found to be significantly (P<0.05) elevated in graft recipients experiencing acute rejection as compared to the non-rejection group. The rise in urinary IL-2R levels in some of the rejection group recipients, was not statistically significant. INTERPRETATION & CONCLUSION Sequential serum and urinary IL-2R assay may serve as a predicter for early graft dysfunction. Study with larger sample size and for longer duration is required to further validate the results.