Type I CG with IgM monoclonal protein (M‐protein) is distinct from the IgG isotype in that it arises in the context of underlying WM, other NHL, or an IgM MGUS, as opposed to Type II and Type III mixed cryoglobulins, which are typically associated with viral infections and autoimmune diseases (see also below) [6]. Here, CD40LG is linked to autoimmune disease.