This percentage is confirmed in the WHO-HAEM5 which recognizes two subtypes of LPL: (1) the IgM-LPL/Waldenström Macroglobulinemia (WM) (about 95%); and (2) the non-WM type LPL (about 5%), including cases with IgG or IgA monoclonal proteins, non-secretory LPL, and IgM-LPL without BM involvement. Here, CD40LG is linked to Waldenstrom macroglobulinemia.