Type I cryoglobulinemia, characterized by the presence of single monoclonal immunoglobulins (typically IgG or IgM) that precipitate with cold temperatures and dissolve with rewarming often occurs in the setting of monoclonal gammopathies or hematological malignancies such as multiple myeloma (11–20%) and Waldenström macroglobulinemia (18–33%) [9]. Here, CD40LG is linked to monoclonal gammopathy.