ABSTRACT
Lymphopenia induced by treatment for acute lymphoblastic leukaemia is analysed and discussed in relation to the type and incidence of infection occurring in those patients during complete remission. Blood lymphocytes can be placed into three largely independent groups: (1) those lymphocytes susceptible to long-term depletion following irradiation; (2) those lost from the blood during and for a short period after maintenance chemotherapy with methotrexate and 6-mercaptopurine; and (3) the remainder which are not depleted by irradiation or maintenance chemotherapy. The number of cells in each compartment varies from child to child and probably with age but on average is about 1.2 x 10(9)/1. for group 1, 0.7 x 10(9)/1. for group 2 and 0.4 x 10(9)/1. for group 3. Conventional lymphocyte typing crosses these barriers in that: Group 1 consists mainly of E-rosetting cells and cells which show a mitotic response to phytohaemagglutinin; Group 2 also contains E-rosetting cells but contains a major proportion of blood lymphocytes with surface immunoglobulin and essentially all antibody dependent cytotoxic lymphocyte (K-cell) activity; Group 3 comprises E-rosetting cells and a few immunoglobulin-staining cells.
Subject(s)
Antimetabolites, Antineoplastic/adverse effects , Leukemia, Lymphoid/therapy , Lymphopenia/etiology , Radiotherapy/adverse effects , Humans , Immunosuppression Therapy , Lymphocytes/drug effects , Lymphocytes/immunology , Lymphocytes/radiation effects , Lymphopenia/immunology , Mercaptopurine/adverse effects , Methotrexate/adverse effects , Radiation Injuries/pathologyABSTRACT
The first and second Medical Research Council UKALL trials have shown that alteration in the timing of methotrexate and 6-mercaptopurine maintenance therapy for the treatment of acute lymphoblastic leukaemia can markedly change drug induced toxicity. Maintenance chemotherapy in both trials used a similar total dosage of these drugs but the timing of their administration was different in the two schedules.