Tissue Study on the Chronic Active Humoral Rejection (cAMR) Population of Kidney Transplantation

Inclusion Criteria: * Age ≥18 years * Kidney transplant recipients * eGFR\>15 ml/min/1.73 sq m at the time of diagnosis of cAMR * cAMR diagnosis defined on the basis of the 2018 Banff Classification (17), made after 1/1/2018. * Obtaining Informed Consent to Participation. Exclusion Criteria: * Combined transplant patients (heart-kidney, liver-kidney or kidney-pancreas) * Histological evidence of concomitant disease (e.g. recurrence of original nephropathy or diagnosis of 'de novo' nephropathy, acute cellular rejection, polyomavirus BK nephropathy, other)