In a subset of subjects on highly active antiretroviral therapy, human immunodeficiency virus type 1 RNA in plasma decays from 50 to <5 copies per milliliter, with a half-life of 6 months

Abstract

Three of five virally suppressed human immunodeficiency virus type I (HIV-1)-infected patients treated with highly active antiretroviral therapy and followed intensively with a supersensitive reverse transcriptase PCR assay with a lower limit of quantitation of 5 copies/ml showed statistically significant viral load decays below 50 copies/ml, with half-lives of 5 to 8 months and a mean of 6 months. This range of half-lives is consistent with the estimated half-life of the latent HIV-1 reservoir in the peripheral blood. Those patients without decay of viral load in plasma may have significant cryptic HIV-1 residual replication.

FIG. 1.

Viral loads in plasma (filled circles) for patients 1, 2, 3, 4, and 5 (PAT 1 through 5) and best-fitting linear regression lines. For patients 3 and 4 the slope of the regression line was not different from zero, and the line is not shown. Data for viral load data were fitted by using a maximum-likelihood procedure that allows for censored data, i.e., data given in the form of <5 copies/ml or <1 copy/ml. We assumed that values reported as <5 copies/ml were between 1 and 5 copies/ml; thus, the data points have associated vertical bars. Similarly, a measurement of 0 is here reported as anything below 1 copy/ml and a vertical bar indicates this uncertainty.