These cells, which primarily produce IgG, IgA, or IgE rather than IgM, are typically IGHV-mutated and function as key players in adaptive humoral immunity.50,51 The increased iron demand in these cells might explain their increased TFRC/CD71 expression, a feature they share with M-CLL cells. This evidence concerns the gene TFRC and B-cell chronic lymphocytic leukemia.