A LOW BLOOD LYMPHOCYTE COUNT IS ASSOCIATED WITH AN EXPANSION OF ACTIVATED CYTOTOXIC LYMPHOCYTES IN PATIENTS WITH B-CELL CHRONIC LYMPHOCYTIC-LEUKEMIA

In order to determine the relationships between CD2+ lymphocyte subpop ulations and tumour mass, the immunophenotype of natural killer (NK) c ells and T lymphocyte subsets was studied in 56 B-chronic lymphocytic leukaemia (B-CLL) patients and 38 healthy subjects. The patients were classified according to their blood lymphocyte count (BLC). Forty pati ents had BLC<30x10(9)/1 (low BLC, less tumour mass) and 16 patients ha d BLC>30x10(9)/1 (high BLC, larger tumour mass). The percentage of CD3 (-)CD56(+) cells, as well as of CD8(+), CD8(+)CD45RO(+) and CD3(+)CD57 (+) T subsets in low BLC patients, were higher than those found in hig h BLC patients. Conversely, the percentages of CD3(+)HLA.DR+, CD4(+) a nd CD4(+)CD45RO(+) lymphocytes were higher in high BLC patients than i n low BLC patients, The CD4/CD8 ratio was decreased in low BLC patient s while it was increased in high BLC patients and a significant positi ve correlation was found between their CD4/CD8 ratio and their BLC. We conclude that in low BLC B-CLL patients there is a decreased percenta ge of activated helper lymphocytes and an increased percentage of NK c ells and activated cytotoxic T lymphocytes. These results suggest a ro le for NK cells, and helper and cytotoxic T lymphocytes in the control of tumour burden in B-CLL patients.