To investigate the variations of Donor Specific Antibodies in kidney transplant patients based on the type of immunosuppressive therapy adopted and immunosuppressive blood levels.

Retrospective observational monocentric study at the U.O.C. of Hepatobiliary Surgery and Transplants of Tor Vergata Polyclinic. All kidney transplant patients in the indicated study period will be enrolled and followed at the U.O.C. clinic.

For each patient, demographic, transplant and post-transplant data will be collected. In the latter, data relating to dnDSA will be registered, searching for a possible triggering cause at the anamnestic level.

The dosage of dnDSA is performed in common clinical practice in a routine manner in all patients undergoing kidney transplant, using the method "Flow cytometric analysis using FlowPRA Screening Test and/or Luminex Single Antigen Beads class I and II- IgG (cut- positivity off = MFI> 1000)".

The blood dosage of the immunosuppressor is measured during routine checks and a comparison is made between Tacrolimus-based immunosuppressive therapy and other immunosuppressive therapy, highlighting the differences in the risk of developing dnDSA and in graft and patient survival.

Inclusion Criteria:

• Patients,both male and female over the age of 18
• Patients with at least one year of follow-up

Exclusion Criteria:

• Combined liver-kidney or pancreas-kidney transplants
• Re-transplants
• Patients with follow-up less than one year

The study population will be composed by patients who underwent a kidney transplant, single or double, from a deceased or living donor, from 01/01/2010 to 07/31/2023 at the U.O.C. of the Hepatobiliary Surgery and Transplants of the Tor Vergata Polyclinic, with at least one year of post-transplant follow-up.