While the underlying differences between IgG4-RD patients with normal and high CRP remain unclear, Kasashima et al[23] recently reported excessive levels of local and serum IL-6 in patients with IgG4-related inflammatory aortic aneurysms, with alternatively activated (M2) macrophages in the adventitia producing IL-6. This evidence concerns the gene CRP and immunoglobulin G4-related sclerosing disease.