In the context of hematological diseases, both type I (monoclonal IgMs or IgGs, rarely IgA) and type II cryoglobulinemia (mixed forms, usually associated with HCV infections or connective tissue diseases occur in MGUS, or B cells malignancies (WM, chronic lymphocytic leukemia, CLL), with a predominance of type II cryoglobulinemia in WM [29,30]. The gene discussed is CD79A; the disease is B-cell chronic lymphocytic leukemia.