The influence of gemcitabine on the CD4/CD8 ratio in patients with solid tumours

Gemcitabine (dFdC) is a novel pyrimidine antimetabolite with documented antineoplastic activity against metastatic non-small cell lung cancer (NSCL), pancreatic carcinoma, ovarian and breast cancer. The side effects of gemcitabine are generally mild; severe infections are reported in less than Ilo of patients. In contrast, other new nucleoside analogues such as the purine antimetabolite fludarabine lead to a significant alteration of the CD4/CD8 lymphocyte ratio associated with an increased risk for opportunistic infections. This study investigates the effect of gemcitabine on different lymphocyte subsets during consecutive applications. 16 patients with solid rumours (3 non-small cell lung cancer, 3 pancreas, 3 testicular, 2 breast, ovarian germ-cell, 1 ovarian, 1 small cell lung, 1 gastric cancer, 1 carcinoma of unknown primary); 15 patients were previously treated, received at least 3 applications of gemcitabine (1,000 mg/m(2) as a 30 min infusion, at days 1, 8, 15; q 4 weeks). Lymphocytes surface antigens were analysed by standard technique flow cytometry prior to every infusion. The median number of leukocytes before therapy was 7823/mu l, with lymphocytes 875/mu l, including 68% T-cells (CD3(+)), 9% B-cells (CD19(+); CD20(+)) and 15% NK-cells (CD56(+); CD16(+); CD3(-)), the CD4/CD8 ratio was 1.7. After gemcitabine therapy the median number of leukocytes was 5136/mu l, with lymphocytes 1012/mu l, including 77% T-cells, 8% B-cells and 10% NK-cells and a CD4/CD8 ratio of 2.2. Severe complications or opportunistic infections were not seen in these 16 patients. No significant change of CD4/CD8 ratios and NK-ccll numbers was seen in our patients with solid tumours during weekly treatment with gemcitabine. A severely increased risk for opportunistic infections following treatment with the new antimetabolite gemcitabine appears unlikely.