ddcfDNA in Kidney Transplant Recipients

Inclusion Criteria: * Recipients aged 18 and above * Patients with de novo DSA positivity post-kidney transplantation and stable renal function: De novo HLA DSAs encompass both class I and class II, with Mean Fluorescence Intensity (MFI) greater than 1000. Stable renal function is defined as serum creatinine variation of less than 15% compared to the last 6 months. * Patients with detected de novo HLA-DSAs but did not undergo histological examinations. Exclusion Criteria: * Multi-organ transplant recipients * Recipients with positive preformed DSAs * ABO-incompatible transplant recipients * Pediatric recipients under 18 years old at the time of transplantation * Recipients lost to follow-up observation * atients already subjected to histological examinations due to positive De novo HLA-DSAs.