Type I cryoglobulinemia includes single monoclonal immunoglobulins, generally immunoglobulin M (IgM), infrequently IgG or IgA, while type II and type III are categorized as mixed cryoglobulinemia since they include two types of immunoglobulins (usually IgG and IgM). Here, CD40LG is linked to cryoglobulinemia.