Effectiveness of murine leukemia chemotherapy according to the immune state: reconsideration of correlations between chemotherapy, tumour cell killing, and survival time.
Cyclophosphamide (CPM) chemotherapy (134 mg/kg) of L1210 leukemia is less efficient in mice previously immunodepressed by antithymocyte serum (ATS) than in non-ATS pretreated mice. On the other hand, administration of a higher dose of CPM (403 mg/kg), which kills a greater number of leukemic cells but induces an immunodepression, according to the skin graft test, results in a shorter survival time than does the administration of a lower dose of CPM (134 mg/kg), capable of killing fewer leukemic cells but not inducing such an immunodepression. Thus, it appears that: (1) the antileukemic effect of the same dose of a chemotherapeutic drug is less efficient in immunodepressed than in nonimmunodepressed hosts, and (2) calculation of the number of neoplastic cells killed by a given chemotherapy by extrapolation from the survival time may lead to erroneous conclusions.
D000818:Animals; D000961:Antilymphocyte Serum / Q000494:pharmacology; D002470:Cell Survival; D003520:Cyclophosphamide / Q000008:administration & dosage / Q000627:therapeutic use*; D007109:Immunity; D007165:Immunosuppression Therapy; D007939:Leukemia L1210 / Q000188:drug therapy* / Q000276:immunology / Q000401:mortality; D051379:Mice; D008815:Mice, Inbred Strains; D013601:T-Lymphocytes / Q000276:immunology
D000961:Antilymphocyte Serum; D003520:Cyclophosphamide