Aims: Antibody-mediated rejection (AMR) is the leading cause of early allograft loss, chronic rejection and graft failure. The aim of this research is to clarify useful predictive serum marker for occurrence of AMR in patients after kidney transplantation (KT).
Methods: Forty-two KT patients were studied; 32 with AMR and 10 without AMR. The AMR is confirmed by presence of donor-specific antibodies and positive C4d staining on renal biopsy. Plasma levels of IL-6, procalcitonin (PCT) and CH50 were measured in KT patients and 40 healthy subjects. Statistical analyses were performed by Kruskal-Wallis test.
Results: Median levels of CH50 were 18.20, 46.40 and 28.15 U/mL in KT patients with AMR, KT patients without AMR, and healthy subjects, respectively. And, PCT levels were 0.045, 0.033 and less than 0.020 ng/mL; and IL-6 were 1.93, 3.48, and less than 1.50 pg/mL, respectively. IL-6 and PCT showed no statistically significant differences, but CH50 was significantly decreased in the group with AMR than without AMR after KT (p < 0.0018). Among 32 patients with AMR, early AMR (within 2 weeks after transplantation) cases showed higher PCT (0.3450 ng/mL) than late AMR (0.0380 ng/mL, p = 0.0020) and without AMR (0.0335 ng/mL, p = 0.0010).
Conclusions: The significant decline of CH50 in KT patients with AMR may implicate that the complement system participates in renal antibody-mediated rejection and CH50 would be useful predictive marker for the detection of AMR in KT patients. Also, further evaluation on the usefulness of PCT is needed as a predictive marker of early AMR in KT.