Background: Although viral rebound follows cessation of suppressive antiretroviral therapy in chronic HIV infection, a viremic clinical syndrome has not been described.Objective: To describe a retroviral syndrome associated with cessation of effective antiretroviral therapy in chronic HIV infection.Design: Case reports.Setting: Outpatient HIV specialty clinics in Seattle, Washington, and Boston, Massachusetts.Patients: Three patients with chronic HIV infection who discontinued suppressive antiretroviral therapy.Measurements: Clinical course, plasma HIV RNA levels, and CD4 cell counts before, during, and after cessation of antiretroviral therapy.Results: Within 6 weeks after stopping antiretroviral therapy, each patient experienced a clinical illness that resembled a primary HIV syndrome. This coincided with a marked increase in HIV RNA level and, in two of three patients, a decrease in CD4 cell count. After antiretroviral therapy was restarted, each patient's symptoms rapidly resolved in association with resuppression of HIV RNA and increase in CD4 cell count or percentage.Conclusion: A retroviral rebound syndrome similar to that seen in primary HIV syndrome can occur in patients with chronic HIV infection after cessation of suppressive antiretroviral therapy. [ABSTRACT FROM AUTHOR]