10 patients with the acquired immunodeficiency syndrome (AIDS), AIDS-related complex (ARC), or lymphadenopathy syndrome (LAS) were given 200-250 mg ampligen, a mismatched double-stranded (ds) RNA with in-vitro antiviral activity against human immunodeficiency virus (HIV), twice a week for up to 18 weeks, without side-effects or toxicity. In all 9 patients who were positive for HIV RNA in peripheral blood mononuclear cells before therapy, levels became undetectable between days 10 and 40 of the start of therapy. 6 of the 7 patients with ARC or LAS also showed a progressive reduction in HIV load as measured by co-culture assays. All 10 patients had augmentation of delayed-type hypersensitivity skin reactions. Other changes noted during ampligen therapy included an increase in or maintenance of numbers of helper-inducer T lymphocytes, improvements in HIV-related symptoms, rises in titre of neutralising antibodies against HIV, and restoration of proper functioning of the natural lymphocyte antiviral dsRNA-dependent (2'-5'-oligoadenylate/RNA-ase L) pathway. Thus, in the short term, ampligen seems to have the dual ability to restore immunological function and to control HIV replication.