Similarly, in the analysis of CD74 expression by extracellular flow cytometry on mononuclear cells from peripheral blood of healthy donors, only CD19+ B cells were positive for CD74, whereas CD4 T cells (the putative cellular compartment of ALCL origin) lacked CD74 expression (Figure 1C, lower panel; Figure S1C). This evidence concerns the gene CD74 and anaplastic large cell lymphoma.