Several studies have shown that the number of IgA1+ plasma cells increased in the BM of patients with IgAN [4], [5] and that BMT or peripheral blood stem cell transplantation in patients with leukemia and IgAN resulted in a remission of the leukemia as well as the IgAN [6], [7], suggesting that the producing cells of nephritogenic IgA may be in the BM of IgAN. The gene discussed is IGHA1; the disease is leukemia.