Alteration of lymphocyte function in NZB/NZW mice. IV. Response to levamisole

NZB/NZW F1 female mice received levamisole in an attempt to increase suppressor T cell function. Responses varied with dosage of drug and age of mice. When treatment with 25 microgram/gm doses (intermittent or daily) was begun at 12 weeks of age, nephritis was accelerated in spite of transient reduction of anti-DNA antibodies. When treatment was begun at 4 weeks, or when doses of 250 microgram/gm were given, no clinical effects were observed. In the mice with accelerated disease, delayed hypersensitivity and antibody responses to sheep erythrocytes increased; antibody responses to pneumococcal polysaccharide were unaffected. It is possible that some increased immune responses associated with levamisole are undesirable in murine lupus.