Study of the IgA Repertoire During IgA Deposition Nephropathy.

IgA plays a major role in mucosal and systemic immunity but retains mysterious and ambivalent aspects. They can thus, depending on the situation, prove to be capable of triggering either a protective inflammatory response or, on the contrary, anti-inflammatory and inducing tolerance. Similarly, and for reasons that remain very poorly understood, they can be involved in pathologies where the immune system is itself an aggressor of the body and responsible for immunopathological lesions. The investigator formulates the hypothesis that an inappropriate response of the mucosal immune system to one or more antigens leads to a synthesis of IgA of bad affinity favoring a deposit at the level of the mesangium. It seems important to verify this point by analyzing the IgA repertory of patients with N-IgA and comparing it to that of a control population.