[Cellular immunity during and after high-dose methotrexate therapy in patients with osteosarcoma (author's transl)]

Nine patients with osteogenic sarcoma and one patient with epitheloid sarcoma of bone undergoing treatment with high-dose methotrexate (MTX) therapy were studied immunologically. The following peripheral blood lymphocyte parameters were evaluated: 1-8 days after the intravenous infusion of 7.5 g MTX followed by leucovorin rescue: absolute count/mm3, the stimulatory response to the mitogens, phythemagglutinin (PHA) and pokeweed (PW) and the reactivity in the mixed lymphocyte culture (MLC). The response to PHA remained unaffected during the observation period, whereas the response to PW decreased on the 2nd and 4th day after treatment. The MLC response was inhibited between the 1st and the 4th day. The inhibition manifested itself first in the patients plasma and was demonstrable 48 hours later in the lymphocyte itself. The responsiveness regained normal or even reacted supranormal values about 7 days after treatment. Lymphocyte function remained essentially unaltered after several cycles of treatment. Absolute lymphocyte counts, however, tended to decrease. The MTX sensitive period in vitro lasts from the 2nd to the 6th day of the MLC, which is the period of intense RNA and DNA synthesis. We conclude that high-dose MTX therapy for osteogenic sarcoma leaves the patient without major permanent damage to cellular immune function.