Читать книгу Assisted Reproduction Techniques - Группа авторов - Страница 35

It is estimated that globally nearly 40 million people are infected and living with HIV with 1.7 million new infections reported annually [1]. The majority of cases occur in men who are young, and many will later desire to have children. The advent of effective antiretroviral therapies allows infected individuals the opportunity to live relatively normal lives and has dramatically improved life expectancy. However, the known risk of sexual transmission of HIV endangers their partners and offspring unless measures to safeguard against infection, such as condom only sex, are practiced. Past reports of estimated male‐to‐female transmission risk ranged from 1 in 100 to 1 in 200 acts of intercourse [2], but the risk can be decreased substantially if the unaffected partner is prescribed pre‐exposure prophylaxis (PrEP) therapy [3–5].

Since 1992 a relatively simple method for processing the semen of HIV‐seropositive men has been used to separate the seminal plasma and nonmotile cellular components (e.g. lymphocytes and other CD4 receptor positive cell lines) from the motile spermatozoa [6]. HIV is a retrovirus that primarily infects T lymphocytes and other immune cells and is also present as free virus in semen and other body fluids. Spermatozoa do not express CD4, CCR5 and CXCR4 receptors and therefore are unlikely to be a significant vector of HIV infection [7].

“Sperm washing” of HIV‐seropositive men is best performed by laboratories specially equipped to handle virally infected patients. Samples are prepared in class II biologic hoods located in a separate area outside of the embryology laboratory. Fresh samples used for IUI or ICSI are first processed by centrifugation in a discontinuous density gradient. Then, two different methods have been utilized to separate the sperm from the seminal plasma. In the originally described method, the sperm pellet is resuspended and centrifuged again before preparation with a final swim up stip. Thus, the specimen is “double washed with swim up” prior to use [8]. A different method has also been proposed using a polypropylene tube insert during the centrifugation step, thus eliminating the need for the “double washed swim up” step. The latter method led to a 98.1% and 100% effectiveness in eliminating HIV‐DNA and HIV RNA from semen samples, respectively [9,10].