Implications of MYD88^L265Pmurine model for human LPL/WM. (A) MYD88 expression in plasmacytoid lymphocytes in BM biopsies from LPL/WM patients without (n = 11) and with (n = 13) MYD88^L265P mutation as evaluated by IHC staining. Three representative examples per each group are shown. Note punctate cytoplasmic staining of the MYD88^L265P, but not WT, protein. Scale bars, 5 µm. T-cell infiltration of BM biopsies from LPL/WM patients without (n = 13) and with (n = 13) the MYD88^L265P mutation. Representative IHC stains (B) and graphs (C) depicting the mean ± SD number of CD3⁺ T cells per cell annotated area (mm²) measured with HALO Image Analysis Software. Scale bars, 250 µm. P value was calculated by using Welch’s t test. Mast cell infiltration of BM biopsies from LPL/WM patients without (n = 12) and with (n = 12) the MYD88^L265P mutation. Representative IHC stains (D) and graphs (E) depicting the mean ± SD number of tryptase⁺ mast cells per cell annotated area (mm²) measured with HALO Image Analysis Software. Scale bars, 250 µm. P value was calculated by using Welch’s t test.