Although disease develops within 10 years in most persons infected with human immunodeficiency virus type 1 (HIV-1), some remain symptom-free for prolonged periods.¹,² Most long-term asymptomatic survivors of HIV-1 infection still have evidence of disease progression in the form of declining CD4+ lymphocyte concentrations. However, some rare persons not only are asymptomatic but also maintain stable levels of CD4+ lymphocytes in the normal or near-normal range. Although the definition of nonprogression may vary, approximately 5 percent of seropositive persons have shown no HIV-related disease or declines in CD4+ cell counts despite 10 or more years of documented HIV-1 infection. . . .