Exciting Developments in HIV Research

Michael and I were just discussing the recent New England Journal of Medicine article regarding reduction in HIV transmission rates. The study found that men at high risk for HIV (in this study, specifically men who have sex with men and transgender women who have sex with men) had a 44% reduction in HIV incidence when they took a standard antiretroviral drug as prophylaxis. It is extremely exciting to hear this news. Antiretroviral therapy has long been used as post-exposure prophylaxis (such as occupational exposure in the form of needle sticks) to reduce conversion rates, but this study suggests that preexposure prophylaxis is a viable option, as well. Obviously you'd have to take the pill everyday, and you'd have to be able to return to a physician for regular checks of kidney and liver function, etc. The men/women in the study also received counseling regarding safe sex practices--which should not be deemphasized in the least. Regular check-ins with a physician who is open to discussing high-risk lifestyles and ways of reducing risk is paramount in helping patients to make more educated decisions about their health. The study indeed found that enrolled subjects showed reduced high-risk behavior compared to before they began the trial. The authors note that the pill itself may be a daily reminder of the risk of HIV.

I found this last idea very interesting. There are many reasons why patients do not take their HIV medication. But some patients report that the pill is a daily reminder of their disease--and that idea depresses them to the point where they avoid their pills in order to "forget." In a personal aside, I had to take HIV prophylaxis for 30 days after I was exposed to HIV+ blood in the form of a stick from a dirty scalpel during my 3rd year vascular surgery rotation. I had to hang reminders in my bathroom mirror so that I wouldn't forget to take my pills before I dragged myself to the hospital at 4am. Regardless, I can definitely speak to the psychological toll of taking specific medications. Every time I took that pill, I was again reminded of my risk (which was very low--but, let's face it, no one wants that risk) and again got a deadening rush of anxiety and despair. I was fine in the end, and stronger for the entire experience, but I can't help but ruminate on the fact that I only had to take the pills for 30 days. Imagine the idea of having to be reminded of your HIV status for a lifetime. If the act of taking a pill can garner such strong emotion, perhaps preexposure prophylaxis is therefore a great way to remind patients of the potential dangers of unprotected sex--and therefore motivate them to always use protection.

The immediate negative backlash is, of course, the opposite of what the study showed. Much like one of the initial arguments against birth control, some may argue that this preexposure prophylaxis would lead to more unprotected sex as those who take the pill may feel that they are unlikely to convert even if exposed to HIV. I am not of this camp. Above all else, getting preexposure prophylaxis would mean that a patient is hooked into the "system." He/she will have a doctor who prescribes the med, performs regular serotesting, and counsels the patient regarding condom usage. Such sustained support and education, again, cannot be underemphasized.

Furthermore (I'm sure Michael has a lot to say about this), this is an option that can be made available to women in 3rd world nations who are not able to refuse sex or demand that their partner use a condom. This is an option that would give women the power to better protect themselves without having to engage their partner in the decision.

But I'm not done with my exciting HIV news! What completely amazed me is another article that I stumbled across while looking up references for lab.

An article in Blood (from Dec. 8th) is from a group of doctors in Berlin who claim that their patient has been CURED of HIV. The patient was both HIV+ and suffering from a relapse of acute myeloid leukemia (AML). For the AML, he was treated with a stem cell transplant, which is basically performed by ablating a patient's own blood cells and replacing them with donor cells. The interesting twist in this story is that the patient's cells were replaced with stem cells from a donor who lacks CCR5. Patients homozygous for the trait are resistant to most strains of HIV infection because HIV requires CCR5 to enter into and infect cells. It is a very rare trait. This patient, after a very grueling medical treatment, has come out on the other side as no longer HIV+. His titers are negative, biopsy material is negative, and, what's even more interesting, all of the myeloid cells in his body have been entirely replaced with the donor cells (which are CCR5 negative). His Kupffer cells (special cells in the liver), microglial cells (special cells in the brain)--everything and anything that HIV could possibly infect.

While lymphoablating someone in order to give them a stem cell transplant is not a viable option for regular treatment of HIV+ patients, this study definitely is a step in the right direction in understanding the role of CCR5 in HIV. HIV mutates constantly, and patients can be infected by more than one strain, so even if this man is indeed cured, there is potential for rebound of a virus that has mutated to no longer require CCR5 to enter cells. Regardless, what an amazing story for this man, and hopefully a giant step in the right direction for HIV research.