CD40LG and plasma cell myeloma: The diagnosis of non-IgM MGUS is established in the presence of a minor clonal plasma proliferation in the bone marrow associated with the secretion of a paraprotein of non-IgM type or a single light chain as defined by the International Myeloma Working Group (IMWG) in 2014 and adopted in the ICC 2022 [13, 60].