My husband was diagnosed with HIV (& AIDS) 8 years into our marriage. I have tested negative 6 times in the 2 years since. In tracking his infection, we have been able to find all but one partner. Each one we have found has tested negative for HIV. The only one left is his first girlfriend from 12+ years ago.

So, to my understanding, my husband has had HIV since the day we met. We have a very healthy sex life. We've had unprotected sex for over 8 years and have a child. How can I not have HIV? Is it possible that I am 'carrying' it? Our doctors tell us to just be thankful, but I really would like to understand.

Thank you in advance for your response.

Your case does not represent the norm, but there are people who have been repeatedly exposed to HIV through sexual contact and have not been infected. It is not always possible to determine why some people get HIV infected and some do not. Factors such as your partner's viral load or your immune system can all play a role in determining the probability of infection.

Researchers have been examining cases like yours to determine if some people have a natural immunity to HIV. In order for HIV to infect a person, it first needs to bind to a CD4 cell and then rely on a co-receptor to gain entry into the cell. These co-receptors are referred to as chemokines. Test tube studies have shown that defects in these chemokine receptors prevent HIV's entry into CD4 cells, thereby preventing infection. Epidemiologic studies have identified an association between HIV-negative individuals with repeated high-risk exposures and defects in certain chemokine receptors. However, individuals with defects in certain chemokine receptors have not consistently demonstrated immunity to HIV infection. Chemokine receptors play an important role in understanding HIV infection and developing methods to protect individuals from infection.

Since it is not clear why you have not been infected with HIV by your husband, it is important that you both continue to practice safer sex.

RMK