Immunoregulatory T-lymphocyte functions in patients with small cell lung cancer

The present study was performed to elucidate the differences in immune status between patients with small cell lung cancer (SCLC) and those with non-small cell lung cancer. The study group consisted of 18 patients with SCLC and 15 with non-SCLC. Two healthy volunteers and 13 patients with benign disease were also included in the present study as the non-cancer control. In the non-SCLC group, although not statistically significant, the percentages of both OKT3+ and OKT4+ T-lymphocytes in the peripheral blood lymphocytes (PBL) were slightly decreased, associated with a slight increase in the percentage of OKT8+ T-cells, and a slight decrease in the OKT4+ to OKT8+ T-cell ratio. In contrast, the PBL of the SCLC patients showed significantly lower proliferative responses to phytohemagglutinin and human recombinant interleukin 2 than did the PBL of both the SCLC patients and the noncancer control group. The ability of PBL to produce lymphokines (interleukin 2 and macrophage activating factor) was significantly impaired in the SCLC group but not in the non-SCLC group. These results suggest that suppression of helper T-cell functions and/or potentiation of suppressor T-cell functions should occur in patients with SCLC.