HIV Shedding in Semen - Causes and Genitourinary Tract Consequences

Robert Coombs, MD, PhD

This research project is studying shedding of HIV-1 virus in semen and its implication for sexual transmission (R01-DK, PI-John Krieger, MD, UW). Contact with semen is the major mechanism for sexual transmission of HIV-1 but information on the biological and cellular factors determining the rate, timing and levels of HIV-1 in semen is limited. The overall goal of this project is to test the hypothesis that HIV virus load in semen is highly variable over the course of infection and is influenced by both systemic and local urogenital factors; and to develop strategies to reduce HIV transmission by lowering the HIV-1 virus load in semen. The specific aims are to:

1. Correlate shedding of HIV-1 with host factors. The investigators are measuring levels of HIV-1 in semen to determine if increases in shedding are associated with (a) advanced clinical stage of infection, (b) genitourinary tract signs and symptoms, (c) reduced cellular immune status, or (d) absence of antiretroviral therapy.
2. Correlate shedding of HIV-1 with the cellular immune response in semen. In this specific aim, the investigators are evaluating the hypothesis that the local cellular immune response in semen limits the shedding of HIV-1. CD4+, CD8+, and peripheral mononuclear absolute cell counts and percentages in semen are measured and compared with HIV-1 titers to determine if men with higher cell counts in semen have lowered titers of HIV.
3. Determine if CMV shedding in semen enhances shedding of HIV-1. HIV-1 and CMV titers are measured by polymerase chain reaction (PCR) and the presence of infectious virus is evaluated with cell culture systems.

Report courtesy of Anna Marie Beckmann

---

Recent Publications

Krieger JN, Coombs RW, Collier AC, Ho DD, Ross SO, Zeh JE, Corey L. Intermittent shedding of human immunodeficiency virus in semen: implications for sexual transmission. J Urol 1995; 154:1035-40.

Coombs RW, Speck CE, Hughes JP, Lee W, Sampoleo R, Ross SO, Dragavon J, Peterson G, Hooton TM, Collier AC, Corey L. Association between culturable human immunodeficiency virus type 1 (HIV-1) in semen and short-term variation of HIV-1 RNA levels in semen and blood: evidence for compartmentalization of HIV-1 between semen and blood. J Infect Dis: 1998; 177: 320-330.

Krieger JN, Nirapathpongporn A, Chaiyaporn M, Peterson G, Nikolaeva I, Akridge R, Ross SO, Coombs RW . Vasectomy and human immunodeficiency virus type 1 in semen. J Urology; 1998; 159:820-826.

Muller CH, Coombs RW , Krieger JN. Effects of clinical stage and immunological status on semen analysis results in human immunodeficiency virus type 1–seropositive men. Andrologia 1998; 30: 15-22.

Speck CE, Coombs RW, Koutsky LA, Zeh J, Corey L, Hooton TM, Collier AC, Ross SO, Cent A, Dragavon J, Lee W, Johnson EJ, Sampoleo RR, Krieger JN. Risk factors for HIV-1 in semen: detection by coculture and polymerase chain reaction. Amer J Epidemiology 1998; (in press).