Given that we found a similar pattern of BTLA expression both at the cell surface and in the cytoplasmic compartment (Figure 2), we could exclude disturbed intracellular BTLA trafficking as the cause of surface BTLA expression changes in CLL T cells, suggesting instead alterations in the BTLA gene activity or epigenetic regulation. The gene discussed is BTLA; the disease is B-cell chronic lymphocytic leukemia.