Undetectable Plasma Viral Load Research Articles

Induction of Long-Term Protective Effects against Heterologous Challenge in SIVhu-Infected Macaques

A group of three rhesus macaques were inoculated with SIV isolated from a human (SIVhu) accidentally exposed and infected with SIVsm. Extensive sequence analyses of SIVhu obtained from the human and macaques following infection indicated the presence of truncated nef. Not only did nef fail to repair itself in vivo postinfection (p.i.), but instead, further mutations added additional stop codons with increasing time p.i. Infection of these animals was associated with minimal acute viral replication, followed by undetectable plasma viral loads and only intermittent PCR detection up to 5 years p.i. The three SIVhu infected and three control monkeys were then challenged with the heterologous highly pathogenic SHIV89.6p. All three controls became infected and showed rapid declines in peripheral CD4+ lymphocytes, disease, and death at 10 and 32 weeks p.i., respectively. In contrast, all three animals previously infected with SIVhu are healthy and exhibit stable CD4+ lymphocyte levels and undetectable plasma viral loads at >20 months post-SHIV89.6p challenge. Only transient, low levels of SHIV replication were noted in these animals. Whereas responses to SIVgag/pol were noted, no evidence for SIV/SHIV envelope cross-reactivity was detected by antibody or CTL analyses, suggesting that the protective immune mechanisms to the heterologous challenge isolate were most likely not directed to envelope but rather to other viral determinants.

Naive CD4+ T lymphocytes express high levels of Bcl-2 after highly active antiretroviral therapy for HIV infection.

The mechanism causing the increasing number of peripheral T cells after highly active antiretroviral therapy (HAART) is still unclear. The bcl-2 oncogene prevents spontaneous apoptosis (SA) in lymphocytes. Spontaneous apoptosis could be a determinant of HIV immunodeficiency and can be reversed by HAART including protease inhibitors (PI-HAART). The aims of our study were to measure Bcl-2 protein expression in memory (CD45RO+) and naive (CD45RO-) CD4+ and CD8+ T lymphocytes of HIV+ patients and to correlate it with efficacy of PI-HAART. Forty-nine HIV+ patients (cases) and 26 HIV- individuals (controls) were evaluated. Patients receiving PI-HAART, and who had undetectable HIV plasma viral load (VL-, n = 21), had higher levels of Bcl-2 than did VL+ patients (n = 28), both in CD4+ cells (p < 0.0001) and in CD8+ cells (p < 0.001). VL+ patients had lower Bcl-2 levels than did controls in CD8+ cells (p = 0.02), but not in CD4+ cells (p > 0.05). Interestingly, VL- patients had higher Bcl-2 expression than did controls both in CD4+ cells (p < 0.0001) and in CD8+ cells (p = 0.03). In a subcohort of the same patients, Bcl-2 was significantly higher in VL- patients (n = 10) than in controls (n = 12), both in naive CD4+ cells (p < 0.0001) and in naive CD8+ cells (p = 0.01). Naive CD4+ cells had higher Bcl-2 expression in VL- than in VL+ patients (p = 0.01). In a subsequent longitudinal study of nine HIV patients, naive CD4+ cells increased after effective PI-HAART (p = 0.03), which paralleled an increase in Bcl-2 expression in the same cells (p = 0.02). In conclusion, upregulation of bcl-2 could be a mechanism of immune reconstitution of naive CD4+ T cells induced by PI-HAART.

Effects of lipolysis or heat treatment on HIV-1 provirus in breast milk.

Transmission of HIV-1 infection through breastfeeding is associated with integrated DNA (provirus) in milk cells. Reduction of HIV-1 DNA in milk may lessen infectivity. To investigate efficacy of two methods available in developing countries to reduce HIV-1 proviral DNA in breast milk. Methods simulated field conditions; milk was heated by bringing it to a boil, for instance, over a cooking fire, and lipolysis was done at room temperature. Four HIV-positive pregnant women were recruited for this pilot study, instructed to feed formula exclusively, and to stimulate milk production using pumping. Milk was collected twice weekly for 3 weeks and analyzed qualitatively for HIV-1 proviral DNA by polymerase chain reaction at three stages: 1) fresh, 2) after standing for 6 hours, and 3) after having been brought to the boiling point. Seventeen samples from 4 mothers were analyzed. Fifteen of 17 fresh samples (88%) had measurable HIV-1 proviral DNA despite all mothers' having had low or undetectable plasma viral loads. Lipolysis (standing at room temperature) for 6 hours did not destroy proviral DNA: 6 of 7 samples (86%) tested positive for DNA after lipolysis. No samples of milk (n = 8) brought to a boil were positive for HIV-1 proviral DNA (p <.0001). This preliminary evidence suggests that inherent lipolytic activity of fresh breast milk is inadequate for destruction of HIV-1; bringing breast milk to a boil may result in decreased HIV-1 infectivity; and breast milk cell-associated HIV-1 may not reflect plasma viral load. Nutritional value or possible bacterial contamination of milk treated in this manner was not assessed.

Rapid Communications

Background: Transmission of HIV-1 infection through breastfeeding is associated with integrated DNA (provirus) in milk cells. Reduction of HIV-1 DNA in milk may lessen infectivity. Purpose: To investigate efficacy of two methods available in developing countries to reduce HIV-1 proviral DNA in breast milk. Methods: Methods simulated field conditions; milk was heated by bringing it to a boil, for instance, over a cooking fire, and lipolysis was done at room temperature. Four HIV-positive pregnant women were recruited for this pilot study, instructed to feed formula exclusively, and to stimulate milk production using pumping. Milk was collected twice weekly for 3 weeks and analyzed qualitatively for HIV-1 proviral DNA by polymerase chain reaction at three stages: 1) fresh, 2) after standing for 6 hours, and 3) after having been brought to the boiling point. Results: Seventeen samples from 4 mothers were analyzed. Fifteen of 17 fresh samples (88%) had measurable HIV-1 proviral DNA despite all mothers' having had low or undetectable plasma viral loads. Lipolysis (standing at room temperature) for 6 hours did not destroy proviral DNA: 6 of 7 samples (86%) tested positive for DNA after lipolysis. No samples of milk (n = 8) brought to a boil were positive for HIV-1 proviral DNA (p < .0001). Conclusions: This preliminary evidence suggests that inherent lipolytic activity of fresh breast milk is inadequate for destruction of HIV-1; bringing breast milk to a boil may result in decreased HIV-1 infectivity; and breast milk cell-associated HIV-1 may not reflect plasma viral load. Nutritional value or possible bacterial contamination of milk treated in this manner was not assessed.

Detection of infectious HIV in circulating monocytes from patients on prolonged highly active antiretroviral therapy.

The existence of a reservoir of resting CD4+ T cells harboring latent replication-competent HIV has been demonstrated in patients on prolonged highly active antiretroviral therapy (HAART). Latently infected tissue macrophages may constitute a second HIV reservoir. The pool of these cells may be maintained by incoming infected monocytes from blood and/or by in situ viral replication. In this study, the presence of infectious HIV was investigated in highly purified monocytes from 5 patients receiving HAART with undetectable plasma viral load for up to 16 months. HIV was detected in freshly isolated monocytes and recovered following Staphylococcus aureus Cowan strain 1 (SAC) or lipopolysaccharide (LPS) activation. No new drug resistance-associated mutation was found in monocyte-associated HIV. These results demonstrate the long-term persistence of infectious virus in cells of the monocyte-macrophage lineage in patients receiving HAART. These cells are capable of releasing infectious virus under appropriate stimulations.

Detection of Infectious HIV in Circulating Monocytes From Patients on Prolonged Highly Active Antiretroviral Therapy

Summary: The existence of a reservoir of resting CD4+ T cells harboring latent replication-competent HIV has been demonstrated in patients on prolonged highly active antiretroviral therapy (HAART). Latently infected tissue macrophages may constitute a second HIV reservoir. The pool of these cells may be maintained by incoming infected monocytes from blood and/or by in situ viral replication. In this study, the presence of infectious HIV was investigated in highly purified monocytes from 5 patients receiving HAART with undetectable plasma viral load for up to 16 months. HIV was detected in freshly isolated monocytes and recovered following Staphylococcus aureus Cowan strain 1 (SAC) or lipopolysaccharide (LPS) activation. No new drug resistance-associated mutation was found in monocyte-associated HIV. These results demonstrate the long-term persistence of infectious virus in cells of the monocyte-macrophage lineage in patients receiving HAART. These cells are capable of releasing infectious virus under appropriate stimulations.