Autoreactive B Cells in Membranous Nephropathy

Inclusion Criteria: Patients inclusion criteria * Males and females. * Adults (\> 18 years old). * Patients with biopsy-proven idiopathic MN, who are candidate to receive (prospective cohort) or who already received (retrospective cohort) a B-cell depleting treatment as per center clinical practice. * Mental state is such that they are able to understand and give valid consent to the study; * Written informed consent according to the guidelines of the Declaration of Helsinki. Healthy volunteers inclusion criteria * Male and female (\>18 years) not known to suffer of any significant illness; * Not assuming any medication or drug on a regular basis; * Negative urine analysis (urine dipstick, multistick); * Written informed consent according to the guidelines of the Declaration of Helsinki Exclusion Criteria: Patients exclusion criteria * Reasonable possibility of a secondary cause of MN (e.g.systemic lupus erythematosus, active hepatitis B, malignancy, drugs such as gold salts and penicillamine). * Legal incapacity, intellectual disability/mental retardation, dementia, uncooperative attitude or any other evidence that patient will not be able to understand the study procedures and aims and to give written informed consent. Healthy volunteers exclusion criteria \- Legal incapacity, intellectual disability/mental retardation, dementia, uncooperative attitude or any other evidence that patient will not be able to understand the study procedures and aims and to give written informed consent.