HIV in Semen of Men Receiving HAART-
The recent NATAP newsletter, NATAP Guide to HIV Treatment Options and Surviving with HIV, reported in brief on page 3 the findings presented at the IDSA meeting in November '98 by Roger Pomerantz regarding a virus reservoir in the semen of HIV infected men. This report is a more detailed review of the study published by Hui Zhang, Pomerantz and others in the New England Journal of Medicine December 17, 1998 issue, Vol 339, Number 25, page 1803.
Investigators collected peripheral blood and semen samples from 7 men with HIV who were receiving HAART and who had <50 copies/ml in plasma, and analyzed the samples for cell associated proviral DNA using a quantitative polymerase chain reaction assay. Replication competent viruses were evaluated by cellcoculture assays. Proviral DNA and replication competent virus from peripheral blood and seminal cells were examined for resistance. Replication competent viruses were found from peripheral blood cells in 3 men and from the seminal cells in 2 of those 3 men.
The 7 men all had HIV RNA <400 copies/ml by RT-PCR on 3 occasions at least one month apart. The men had been receiving HAART for 5-41 months and all had pre-treatment HIV-RNA >1000 copies/ml. On the days on which samples of peripheral blood and semen were taken for this study, the plasma HIV-RNA in all 7 men was <50 copies/ml.
Table of Results
Column 1 is patient ID number; column 2 is treatment; column 3 is number of months on HAART; column 4 is CD4 count; column 5 is viral load in plasma and seminal fluid; column 6 is proviral DNA in cells in blood (PBMCs) and seminal cells; column 7 is whether or not replication competent virus was found.
Plasma .-. Seminal Fluid
(per million) PBMCs.-.Seminal Cells
PBMCs ...- ..Sem Cells
|<50 ........ ..<50||8 ................. <5||Neg ........... .Neg|
|<50 ...........<50||7, 15* .. .......<5, <5*||Pos .............Neg|
|<50 ...........<50||25, 30*..........90, 20*||Pos .............Pos|
|<50.. .........<50||5 ...............<5||Neg ............Neg|
|<50 ...........<50||35 ..............5||Pos .............Pos|
|<50 ...........<50||40 ............ .5||Neg ............Neg|
- PBMCs means peripheral blood mononuclear cells
- In patients 3 & 5 the initial protease inhibitor was changed from IDV to NFV
- Pt # 3 was also treated with IL-2
- * pt samples were obtained at least 2 months apart and analyzed on two different days
- Pt 7 was also treated with acyclovir
DNA Detectable in Both Blood Cells & Seminal Cells Although RNA is Undetectable in Blood & Seminal Fluid. As you can see in column 4 HIV-RNA (viral load) in plasma and seminal fluid is <50 copies/ml. Authors say this suugests HAART inhibited viral replication in blood and genital tract. But as you can see in the next column cell associated viral DNA was detected in PBMCs from all 7 men, ranging from 5 to 40 per million peripheral blood mononuclear cells. Call associated proviral DNA was also detected in the seminal cells from 4 men, ranging from less than 5 to 90 per million seminal cells. There was a small decrease in the level of proviral DNA in seminal cells in Patient 4.
Replication Competent HIV was Detected. As you can see in the last column replication competent virus was found from PBMCs from 3 men and seminal cells from 2 of those 3.
Replication Competent Virus is Sexually Transmissible. The authors identified the HIV strains in patients 4 and 6, the patients found to have replication competent virus in their seminal cells. The virus isolated from patient 6 was a typical macrophage-tropic strain, while the virus isolated from the seminal cells of patient 4 had dual tropism. The authors said most HIV transmitted sexually are either of these two strains. Therefore, the authors concluded that the replication competent virus found in the seminal cells of these 2 men are potentially capable of being sexually transmitted, although these 2 men were receiving HAART and had <50 copies/ml in their blood.
The authors said, the infected seminal cells could come in direct contact with CD4s, macrophages and dendritic cells in the mucosa of sexual partners, resulting in transmission of the virus. The virions produced from the seminal cells after transfer from a man who is receiving HAART to a sexual partner should be infectious because the concentrations of antiviral drugs in the semen would be diluted to low levels.
Resistance. As has previously been reported, HIV resistant to RT and protease inhibitors can be transmitted. To determine if resistance was detectable in the replication competent HIV and proviral DNA isolated from seminal cells and PBMCs in this study, the authors sequenced the RT and protease regions. Although they found a single mutation in the protease gene (at position 10) of the proviral DNA from the PBMCs of patient 4, no drug resistance mutations were detected in either the replication competent virus recovered from the seminal cells or the seminal associated proviral DNA from patient 4 or 6. Similarly, no drug resistance mutations were detected in seminal cell associated proviral DNA in patients 2 and 7. No other drug resistance mutations were detected in the proviral DNA from peripheral blood mononuclear cells from patients 2, 6 or 7. The authors said their studies demonstrate that replication competent viruses from the seminal cells remain sensitive to antiretroviral drugs.
The authors reported that the sequences of the V-3 loop region of the viruses recovered from peripheral blood cells and those recovered from seminal cells from patients 4 and 6 were different and suggested that at least some viral replication is compartmentalized within the male genital tract and the peripheral blood. They said this could be due to very slow turnover of some cells harboring proviral DNA. The authors said this suggests that the genital tract can be a reservoir for viral replication in men. Theoretically, the authors suggested, if no drug resistant mutants developed during HAART there would be no reinfection of cells in "microenvironments" in which there were inhibitory concentrations of the drugs. However, the blood-testes barrier may prevent antiviral drugs from entering the testicular tissue in high concentrations, therefore creating a viral sancutary. Although levels of HIV-RNA were below the level of detection in the seminal fluid (<50 copies/ml) of the men in this study, there still could be covert viral replication in the genital tract, as may occur in lymph tissue.
The sequences suggest, as reported by the authors, that the replication competent viruses found in both seminal and blood cells are derived from the proviral DNA in these cells. Because the sequences isolated from seminal cells differed than those obtained from the peripheral blood cells the infected seminal cells may not have come from the peripheral blood.. The seminal cells could have been infected before therapy was initiated.