To further determine the effect of addition of CD48 antibodies on effector function in terms of CD107a degranulation activity, PBMCs from HTLV-1 infected patients were incubated with and without HTLV-1 Tax peptide in the presence of anti CD48 blocking antibodies and the effect on in-vitro CTL function measured in HTLV-1 infected (12 independent experiments in 8 asymptomatic carrier (AC) samples and 11 experiments in 7 samples with ATLL). This evidence concerns the gene LAMP1 and adult T-cell leukemia/lymphoma.