Reconstitution of NK cell activity in HIV-1 infected individuals receivingantiretroviral therapy

We studied natural immunity mediated by natural killer (NK) cells in 62 HIV -1 infected individuals, 54 HIV-1 infected individuals receiving highly act ive antiretroviral therapy (HAART) for more than one year and 8 HIV-1 infec ted individuals without antiretroviral therapy. 22 individuals had a comple te suppression of viral replication characterized by viral load values <50 copies/ml, whereas 32 individuals presented with persistent viral replicati on. The 8 untreated patients had an indication to start antiretroviral trea tment. Lyric activity of NK cells was measured in a (51)chromium release assay. In patients with persistent viral replication under HAART NK cell activity wa s significantly decreased compared to patients with effective control of HI V viremia. Patients with complete suppression of HIV replication displayed a similar NK activity to healthy control persons. Differences in antibody-d ependent cellular cytotoxicity (ADCC) were not observed. Further studies wi ll investigate whether decreased NK cell activity is a reason for or the co nsequence of persistent viral replication.