EVALUATION OF LYMPHOKINE-ACTIVATED KILLER-CELL DEVELOPMENT IN YOUNG AND OLD HEALTHY HUMANS

The kinetics of the development of lymphokine-activated killer (LAK) c ell activity, the surface phenotype, and the expression of p55 and p75 interleukin 2 receptors (IL-2R) on IL-2-activated peripheral lymphocy tes have been investigated in young and old healthy humans selected ac cording to the Senieur Protocol criteria. No difference is present bet ween young and old healthy subjects in terms of LAK cell activity deve lopment. The proliferative capacity of lymphocytes incubated with IL-2 shows similar kinetics in young and old subjects. The mean percentage s of CD56+ and CD16+ cells reach higher levels in old than in young do nors, The proportion of CD56+/CD25+ cells in culture is significantly higher in old than in young individuals. A progressive decrease of CD4 + population occurs during LAK cell development, both in young and old subjects. The proportion of CD4+ T cells in culture is lower in old t han in young individuals. No age-related difference is present in the mean percentage of cells positive for p55 or p75 IL-2R at any culture time. Thus, our findings show similar kinetics of development of LAK c ell activity in young and old subjects, indicating that aging per se d oes not represent an exclusion criterion of cancer patients from clini cal trials of adoptive immunotherapy. A higher proportion of CD56+ and CD16+ cells seems to be required in old subjects to obtain the same l evels of LAK cell activity present in young age.