title: Cytosine arabinoside induced changes in natural killer and antibody dependent cellular cytotoxicity functions in multiple sclerosis patients.
abstract: Five multiple sclerosis patients were treated weekly with cytosine arabinoside (araC) on an escalating dose schedule. The dose was initiated at 50 mg/M2 and then increased once each week by 50 mg/M2 (unless toxicity caused delay). Dosage decisions were based on whether or not the antibody-dependent cellular-cytotoxicity (ADCC) or natural killer (NK) cytotoxicity levels had been reduced to a level more than 2 standard deviations below the control range. Cytosine arabinoside treatment was discontinued in 2 of 5 subjects at doses of 500 mg/M2 due to toxicity. The 3 remaining patients demonstrated sustained reductions in the percentage of FcR+ cells in their peripheral blood. The maximum percentage reductions from the baseline values ranged from 50% to 76%. Concomitant reductions in the NK activity at the same doses ranged from 65% to 83%. ADCC activity in all 3 patients, however, was relatively resistant to suppression. The nadirs for the ADCC activity were only 16% to 44% below the baseline minimum. AraC was shown to reduce the proportion of FcR+ cells and NK cytotoxic activity in preference to ADCC activity.
mesh_terms: D000920:Antibody-Dependent Cell Cytotoxicity / Q000187:drug effects*; D003561:Cytarabine / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D006801:Humans; D066298:In Vitro Techniques; D007694:Killer Cells, Natural / Q000187:drug effects*; D009103:Multiple Sclerosis / Q000188:drug therapy* / Q000276:immunology; D011961:Receptors, Fc / Q000187:drug effects; D017452:Receptors, IgG
chemical_list: D011961:Receptors, Fc; D017452:Receptors, IgG; D003561:Cytarabine