[Comment] New clues on the pathogenesis of IgG4-related disease come from genomics

IgG4-related disease is a rare fibroinflammatory disorder usually characterised by multiorgan involvement. Several organ-specific conditions once thought to be separate entities, such as chronic sclerosing pancreatitis, Mikulicz's disease (chronic sclerosing dacryoadenitis and sialadenitis), sclerosing mediastinitis, and retroperitoneal fibrosis, are now grouped under the umbrella of IgG4-related disease because they have a common histopathological background (storiform fibrosis and dense lymphoplasmacytic infiltrates rich in IgG4-positive plasma cells) and often increased serum IgG4 concentrations.