Testes Remain an HIV Reservoir Even After Efficient Treatment

World Health Organization data have showed that 39.5 million people were infected with HIV in 2005 and their number is rising.

HIV (human immunodeficiency virus) is a retrovirus that develops inside the cells of the immune systems (the so-called "white cells" of the blood) and provokes the collapse of the immune system, condition named Acquired Immunodeficiency Syndrome (AIDS). Any mild (or even totally harmless under normal conditions) germ will destroy the organism. Finding a cure for this horrible malady is a must.

Recently, researchers have showed that HIV replication within resident immune cells of the testis provides an explanation for the viral persistence in semen even after effective highly active antiretroviral therapy (HAART) have cleansed the blood off the virus. This way, semen (read sexual contact) remains the main way of the virus spreading, despite successful HAART.

A team led by Dr. Nathalie Dejucq-Rainsford investigated testis tissue for the presence of HIV receptors. All required cellular receptors (CD4, CXCR4, CCR5, and DC-SIGN) were present on white cells inside the testis, specifically testicular macrophages. The team studied the issue "in vitro" using lab cultures of human testis tissue. The "in vitro" testis culture, which kept the same tissue architecture as "in vivo" tissue and continued to secrete testosterone, was able to develop infection by HIV-1.

Virus developed in the testis culture was fully active as it was capable of attacking permissive cells in culture. The testes are difficult to be targeted by many other anti-retroviral drugs, as they find it hard to penetrate this organ and may be present at sub-therapeutic levels. This finding shows that even after effective HAART, the patients remain an active vector for the virus dispersal. The development of new more effective anti-retroviral therapy must target all HIV incubator organs, including the testis.