Effector, memory and naïve CD8+ T cells in peripheral blood and pleural effusion from lung adenocarcinoma patients

In the effector CD8+ T subset, from peripheral blood as well as from pleural effusion, a low percentage of perforin-expressing cells was observed compared to granzyme A-expressing cells. Additionally, a high percentage of naïve CD8+ T cells expressing Fas was found. Our data suggest that: (i) terminal-differentiation process of CD8+ T cells is blocked, and (ii) early Fas-expression in CD8+ T cells, which was reflected even in peripheral blood, may lead to apoptosis of naïve cells when they reach the effector stage. All these processes may contribute to the inadequate antitumour immune response found in lung carcinoma patients.