Explanation:Immunoglobulin A (IgA) nephropathy or Berger's diseaseIt is the most common form of primary glomerulonephritis in the worldIgA nephropathy is characterized by the accumulation in mesangial areas of immune complexes containing polymeric IgA1.The pathogenesis of this disease involves the deposition of polymeric and undergalactosylated IgAl in the mesangium.Quantitative and structural changes of IgA 1 play a key role in the development of the disease due to functional abnormalities of two IgA receptors: The Fc alpha R (CD89) expressed by blood myeloid cells and the transferrin receptor 1CD71) on mesangial cells. Abnormal IgA induce the release of soluble CD89 which is responsible for the formation of circulating IgA complexes.These complexes may be trapped by CD71 that is overexpressed on mesangial cells in IgA nephropathy patients allowing pathogenic IgA complex formation.">