The median basal circulating CD19+ B lymphocyte counts were 25.31 (range, 6.23–67.48), 18.2 (range, 16.70–18.50), 15.02 (range, 6.64–19.86), 14.80 (range, 4.60–20.70),10.23 (range, 1.22–27.70), 10.00 (range, 5.00–33.30) and 4.51 (range, 2.10–13.10) for MCL, “double-hit” lymphoma, NOS high-grade B-cell lymphoma, Burkitt lymphoma, MALT, mixed B-cell lymphoma and unclassifiable B-cell lymphoma, respectively. This evidence concerns the gene CD19 and mantle cell lymphoma.