Analysis of T- and B-Cell Subpopulations in Membranous Nephropathy

The aim of this observational study is to provide analysis of T and B lymphocyte subgroups in peripheral blood samples of patients with primary membranous nephropathy (MN). A search for disease-related circulating antibodies \[anti-phospholipase A2 receptor antibody (anti-PLA2R) and anti-thrombospondin type 1 domain-containing 7A antibody (anti-THSD7A)\] in patients' sera is also planned. The main questions to answer are: 1. What is the relationship of these cell populations and their distribution during follow-up with treatment, treatment responses, and relapses? 2. What is the relationship of the cell populations with anti-PLA2R (or anti-THSD7A) antibody levels? Participants will provide peripheral venous blood samples at pre-designated regular intervals. The research team will compare results of the primary MN group with two control groups (IgA nephropathy and healthy volunteer groups) to see if the findings are specific for primary MN.

Inclusion Criteria: * Having a diagnosis of primary membranous nephropathy (patient group). * Having a diagnosis of primary IgA nephropathy (diseased control group). * Being healthy (healthy control group). * Agreeing to participate in the research (informed consent). Exclusion Criteria: * Refusing to participate in the research.