['We have previously reported that the most significant immunological prognostic factors in patients with lung cancer are the percentages of peripheral HLA-DR+ lymphocytes.', 'We performed two-color flow cytometric analyses using two combinations of double-staining to identify lymphocyte phenotypes HLA-DR/CD4 and HLA-DR/CD8, and examined the correlation between the expression of these subsets and survival in 51 patients with non-small cell lung cancer.', 'The percentages of HLA-DR+, HLA-DR+/CD4+ (activated helper/inducer T cells) and HLA-DR+/CD8+ (activated cytotoxic/suppressor T cells) did not correlate with survival. However, survival was better when the percentage of HLA-DR+/CD8- was below normal (p = 0.0267). The 4-year survival rate in patients with high and low percentages of peripheral HLA-DR+/CD8- lymphocytes was 26.0% and 53.2%, respectively.'] Do peripheral leukocytes with HLA-DR+/CD8- phenotype are associated with prognosis in patients with lung cancer?