[CANCER RESEARCH 31, 420-426, April 1971] The Immunosuppressive Effects of Long-Term Combination Chemotherapy in Children with Acute Leukemia in Remission1 Luis Borella and Robert G. Webster Laboratories of Virology and Immunology, St. Jude Children 'sResearch Hospital, Memphis, Tennessee 38101 SUMMARY effects of prolonged maintained combination chemotherapy upon immunocompetence have not been investigated. The immunosuppressive effects of maintenance Knowledge of the immunosuppressive effects of long-term combination chemotherapy given for periods ranging from 8 combination chemotherapy is now urgently needed because of to 28 months to 20 children with acute lymphocytic leukemia the increasing number of prolonged remissions and potential in remission were investigated. There was depression of both 5-year cures among children with acute lymphocytic leukemia the primary antibody production to the hemagglutinin antigen receiving this form of treatment (19). of the Hong Kong influenza virus and the anamnestic response This study was aimed at determining the to the neuraminidase of the same virus. The primary response immunosuppressive effects of long-term combination (hemagglutination inhibition) was affected to a greater extent chemotherapy in children with acute lymphocytic leukemia. than the secondary (neuraminidase inhibition) response. A Several unique features of this investigation were as follows. preferential depression of 2-mercaptoethanol-resistant (a) All patients were in remission and received the same hemagglutination inhibition antibodies (IgG) was also combination chemotherapy continuously for periods ranging observed. One-fourth of all acute lymphocytic leukemia from 8 to 28 months, (b) Patients and controls were patients had low serum IgG levels. In vitro transformation of immunized with the Hong Kong influenza virus vaccine prior lymphocytes was a poor index of immunocompetence. After 2 to the Hong Kong influenza virus epidemic. This permitted the years of continuous chemotherapy, children with low IgG and assay of the primary antibody response to one of the antigenic suppressed antibody production had normal response to determinants of the virus, the hemagglutinin, and the phytohemagglutinin. This initial study on the secondary antibody response to the other determinant, the immunocompetence of patients with leukemia undergoing neuraminidase (4, 23). (c) The effect of long-term long-term combination chemotherapy should provide a base chemotherapy upon 2 other parameters of line to establish correlations between immunological immunocompetence, lymphocyte response to PHA2 and parameters and infectious complications. serum immunoglobulin levels, was also determined and compared. INTRODUCTION MATERIALS AND METHODS It has been stated that combination chemotherapy is Selection of Patients. Immunological studies were mandatory in the treatment of acute leukemia (10). performed in 20 children with acute lymphocytic leukemia Combination chemotherapy in children with acute and 22 nonleukemic children. All children with leukemia were lymphocytic leukemia at St. Jude Children's Research Hospital in complete remission during the entire period of has resulted in prolonged remissions and a 17% 5-year cure immunological evaluation. They were in the maintenance rate (9, 19). Continuous administration of immunosuppressive phase of the treatment, which consisted of daily 6MP, weekly therapy has, however, increased the risk and severity of MTX, and Cyclo, and a 2-week course of VCR and prednisone infections (15). Several recent reviews discuss the effects of every 10 weeks (Table 1). They had this therapy for periods antineoplastic drugs upon different stages of the immune ranging from 8 to 28 months. Another group of 22 children response in both animals and man (8, 13, 24). Studies in with acute lymphocytic leukemia that were not inoculated humans have been aimed at determining the degree of with the Hong Kong influenza vaccine also received the same immunosuppression in patients receiving short-term courses of maintenance treatment for periods ranging from 4 to 26 single or combined antimetabolites (11-14, 22). However, the months. They were included in this study solely in an attempt to determine clinically whether during an epidemic of 1Supported by USPHS Cancer Research Center Grant CA-08480 influenza there was any difference in the incidence or severity from the National Cancer Institute, USPHS Research Grant AI-08831 of influenza-like illness between vaccinated and nonvaccinated from the National Institute of Allergy and Infectious Diseases, General children with acute lymphocytic leukemia. Research Grant RR-05584 from the NIH, and by ALSAC. 2The abbreviations used are: PHA, phytohemagglutinin; 6MP, All patients with acute lymphocytic leukemia had complete 6-mercaptopurine; MTX, methotrexate; Cyclo, cyclophosphamide; physical examinations, including white blood cell, differential, VCR, vincristine. and platelet counts, weekly. The doses of antineoplastic drugs Received September 8, 1970; accepted December 3, 1970. were adjusted for each individual patient to maintain the white 420 CANCER RESEARCH VOL. 31 Downloaded from cancerres.aacrjournals.org on September 23, 2021. © 1971 American Association for Cancer Research. Immunosuppression in Acute Leukemia Table 1 extensively dialyzed against phosphate-buffered solution after Maintenance combination chemotherapy of children with acute treatment with 2-mercaptoethanol. lymphocytic leukemia in remission Criteria for Clinical Diagnosis of Influenza. The children in Immunological parameters were determined in 20 children with this study were vaccinated against Hong Kong influenza virus acute lymphocytic leukemia in remission receiving this maintenance treatment for periods ranging from 8 to 28 months. during the first 2 weeks of December 1968. Written parental consent was obtained in all cases. The Hong Kong influenza epidemic was first detected in the local community (Memphis, DoseDrug Tenn.) on December 20, 1968, reached a peak on January 10, Route6MPMTXCycloPrednisoneVCR5020200401.5P.O.p.o.(mg/sq m) 1969, and was over by January 31,1969. The following list of symptoms was considered for clinical diagnosis of influenza ori.v.p.o. virus infection during the epidemic period: fatigue, headache, ori.v.p.o.I.V.ScheduleDailyWeeklyWeeklyDaily myalgia, temperature over 38°, lacrimation, coryza, sore for 15Weekly weeksweekss every 10 throat, cough, hoarseness, nausea, and vomiting. Since for 3day every 10 weeks identification of the virus was not attempted, we have used the term influenza-like illness rather than influenza to describe the infections. Siblings of leukemic children served as normal blood cell count between 2000 and 3000/cu mm. The control controls. group consisted of 22 children without neoplastic diseases seen In Vitro Stimulation of Peripheral Blood Lymphocytes with at the Nutrition and Metabolic Clinic for evaluation of growth, PHA. For avoidance of any interference from previous development, and nutritional status. The age of leukemic and immunization upon the response of peripheral blood control children ranged from 2 to 15 years and the median was lymphocytes to PHA stimulation, this test was performed at 5 years; 38 were female and 26 were male. least 6 months after influenza vaccination. The 13 patients Vaccine and Vaccination. Monovalent type A2/Aichi/2/68 evaluated were still in continuous complete remission and (Hong Kong variant) influenza virus vaccine prepared by zonal receiving the same uninterrupted combination chemotherapy. centrifugation (Zonomune) containing 800 chick cell Fifteen ml of venous blood were removed 7 days after the last agglutinin units/ml was obtained from Eli Lilly and Company, dose of MTX and Cyclo, mixed with 250 units of heparin, and Indianapolis, Ind. The vaccine was administered s.c. at the allowed to sediment for 2 hr at 37°in a 20-ml plastic syringe following dosage: for children over 10 years of age, 0.5 ml; for in a vertical position. The WBC-rich plasma was transferred to children 6 to 10 years old, 0.25 ml; and for children 3 months a sterile tube, and the cells were then cultured in glass tubes to 6 years old, 2 doses of 0.1 ml each at an interval of 2 weeks. according to the method described by Hersh and Oppenheim Viruses. The A2/Aichi/2/68 (Hong Kong) and the (14). Each culture contained 2 X IO6 WBC; 40 to 60% of A2(Tokyo/3/67 (Tokyo) strains of influenza virus were grown these were lymphocytes. Half of the cultures were inoculated in the allantois of 11-day-old chick embryos. The viruses were with 0.025 ml of PHA (Difco Laboratories, Detroit, Mich.). For concentrated by differential centrifugation and stored at 4° each patient and each determination, sets of 4 stimulated and with 0.1% sodium azide as preservative. 4 nonstimulated cultures were established. Three days after Titration of Antibodies to the Hemagglutinin and initiating the culture, 1.5 /uCi of thymidine-3H (Schwarz Neuraminidase Antigens of Influenza Virus. Blood samples BioResearch, Inc., Orangeburg, N. Y.) with a specific activity were obtained before vaccination and at weekly intervals of 3.0 Ci/mmole were added to each tube and the cells were thereafter for 4 weeks. To reduce the immediate suppressive incubated for an additional 18 hr. The cells were washed twice effects of chemotherapy, all blood samples were obtained 7 with 0.9% NaCl solution, and the nucleoproteins were days after the last and immediately before the next weekly precipitated with