Cryoglobulinemia is divided into three types based on immunoglobulin composition: type I (composed of a single monoclonal immunoglobulin, typically associated with lymphoproliferative disorders such as multiple myeloma or Waldenström macroglobulinemia), type II (mixed cryoglobulins consisting of monoclonal IgM with rheumatoid factor activity and polyclonal IgG, most commonly linked to hepatitis C virus infection), and type III (polyclonal IgM and IgG, often related to chronic infections or autoimmune diseases) (1, 2). The gene discussed is CD40LG; the disease is autoimmune disease.