Study of the Link Between Complement Activation and IgA Nephropathy Severity

Inclusion Criteria: * Adult patients, male or female, with a biopsy proven IgA nephropathy. * Primitive and secondary forms can be included * Regardless of the date of diagnosis and the level of kidney function * With or without past of kidney transplantation * Followed in the Nephrology Department, Strasbourg University Hospital * Signed informed consent Exclusion Criteria: * Active or recent infectious or inflammatory syndrome (\<2 months), recent vaccination (\<2 months), ongoing acute humoral rejection treatment, treatment with plasma exchanges (\<2 months), current treatment with complement inhibitors * Impossibility of giving informed information (emergency situation, difficulties in understanding, etc.) * Subject under safeguard of justice, guardianship or curatorship