Evaluation of lymph node virus burden in human immunodeficiency virus-infected patients receiving efavirenz-based protease inhibitor-sparing highly active antiretroviral therapy

Although efavirenz-containing regimens effectively suppress plasma levels o f human immunodeficiency virus (HIV) RNA, it is now clear that undetectable plasma viremia may not reflect a lack of viral replication. Because lympho id tissue is an active site of HIV replication, the lymph node virus burden was analyzed in persons who received highly active antiretroviral therapy (HAART) containing either efavirenz or a protease inhibitor (PI). Testing w ith in situ hybridization revealed no detectable follicular dendritic cell- associated HIV RNA in either group, and only 2 of 8 persons in the efaviren z group and 1 of 4 in the PI group had detectable RNA in lymph node mononuc lear cells (LNMC) when tested by use of nucleic acid sequence-based amplifi cation. Low levels of replication-competent HIV were identified in both gro ups by use of quantitative coculture assays. There was no evidence of devel opment of resistance to either regimen in virus isolated from LNMC. These d ata support the use of efavirenz as an alternative to a PI in initial HAART regimens.