The anti-hinge region antibodies would be a relevant biomarker of IgA nephropathy. Beyond a prognostic value (which could increase the risk of Renal Absolute), the longitudinal monitoring for these antibodies could be of interest: (1) in the monitoring of patients (in place including a possible repetition renal biopsy); (2) to guide treatment decisions and (3) in clinical research, as an outcome (in substitution for the occurrence of kidney failure) in therapeutic trials IgA nephropathy.

This research project constitutes the first step in validating these antibodies biomarker of IgA nephropathy and its main objective is to study the performance of the blood levels of anti-hinge region antibodies in the diagnosis of progressive forms of histologically IgA nephropathy as defined by the Renal Risk Absolute.

The secondary objectives of this project are to establish a bio-collection that will allow us to search for other prognostic factors (genetic, cellular and serum) of IgA nephropathy and to evaluate the performance of Renal Absolute risk by integrating Oxford score, the new international histological classification.

Inclusion Criteria:

• Major Patient
• Diagnosis of a primitive form of IgA nephropathy histologically proven

Exclusion Criteria:

• Suspicion of secondary IgA nephropathy forms
• Less than 5 glomeruli present on renal biopsy