HIV-infected long-term nonprogressors: epidemiology, mechanisms of delayedprogression, and clinical and research implications

Long-term nonprogressors (LTNPs) should be defined as untreated HIV-infecte d persons without AIDS and with high CD4(+) counts and low plasma viral loa ds 10 or more years after infection. Although no demographic or behavioral variables distinguish LTNPs, studies should be expanded to include geograph ically and ethnically diverse groups. Underlying mechanisms for delayed pro gression appear to include strong CD8(+) cytotoxic T-lymphocyte and noncyto lytic suppressive activity, host genetic factors including chemokine recept or polymorphisms, and infection with attenuated viral strains. (C) 1999 Edi tions scientifiques et medicales Elsevier SAS.