Changes of blood T cell subsets in patients receiving postoperative adjuvant chemotherapy for breast cancer.

The number of T helper (Th) and T suppressor (Ts) cells, as defined by monoclonal antibodies, of the blood lymphocyte population was examined in breast cancer patients receiving postoperative cyclic therapy with cyclophosphamide, methotrexate and 5-fluorouracil. The total number of lymphocytes was reduced to approximately 50% at the end of the 17-month period of chemotherapy. Identification of Th and Ts subsets with the aid of Leu-3a and Leu-2a antibodies revealed that the former was reduced to a higher relative extent than the latter, thus reducing the Th/Ts ratio highly significantly during the entire treatment period. A reduced ratio was also observed in a group of patients having completed their treatment 2-3 yr earlier.