CD19 and neoplasm: These structures could be visible by staining, including panel I: CD8+ T cells, CD4+ T cells, PD-1+ cells, PD-L1+ cells, Foxp3+ regulatory T cells (Fig. 3a); and panel II: CD19+ B cells, CD56+ NK cells, CD68+ macrophages, CD163+ M2 macrophages, cytokeratin+ tumor cells (Fig. 3b).