Non-B-derived Ig was frequently expressed in hematopoietic cells, including umbilical cord CD34+ stem/progenitor cells (IgM) [15], AML blasts (IgG, IgM, and Igκ) [16,17,18], and mature myeloid cells (IgM, and Igκ) [17,18]. Here, CD40LG is linked to acute myeloid leukemia.