Strength of Donor-Specific Antibodies With the Use of Luminex Single-Antigen Beads Is a Reliable Predictor of Acute Rejection in Living-Relative Kidney Recipients

Background. Luminex single-antigen assay is a promising technique for determination of donor-specific antibodies (DSAs) in renal transplantation. Methods. Serum samples from living-relative renal recipients before and after renal transplantation were examined with the use of Luminex single-antigen assay. The impact of de novo DSAs on the early clinical outcomes of renal allograft was analyzed. Results. Of the 61 patients included, 15 patients (24.6%) presented de novo DSA (4 class I, 4 class II, and 7 both classes) after transplantation, and the average (median) cumulative strength of DSA was 1,283 (range, 0-10,802) mean fluorescence index (MFI) for class I versus 1,324 (range, 0-14,985) MFI for class II (P>.05). Twelve (19.7%) of the 61 patients experienced a clinical/subclinical acute rejection (AR) episode within the 1st 2 years after transplantation. A clinical/subclinical AR episode was diagnosed in 40% of DSA(+) patients and 13.0% of DSA(-) patients (P<.05). DSA(+) patients who developed an AR episode had a higher mean cumulative MFI value (8,118.3 +/- 5,287.4; range, 1,785-14,985) than patients who did not develop an AR episode (3,283.7 +/- 2,601.0; range, 786-8,113; P<.05). Serum creatinine levels in the DSA() group were significantly higher than in the DSA(-) group at 12 and 24 months after transplantation. The graft survival rates at 2 years in the DSA(+) and DSA(-) groups were not different (86.7% vs 91.3%; P>.05). Conclusions. Patients with de novo DSAs at high strength may suffer a high risk of developing an AR episode. Therefore, careful monitoring of de novo DSAs with the use of Luminex single-antigen beads may help in early intervention for AR in renal allografts and to minimize renal damage caused by the antibodies.