In a bone marrow transplant, a patient’s own marrow is destroyed and replaced with tissue from a donor. The donor marrow contains healthy hematopoietic stem cells (HSCs, adult stem cells in the blood) which repopulate the patient’s body with healthy red and white blood cells for oxygen transport and immune defense. Just as with other varieties of organ donation, tissue-type matches are critical. In the case of the AIDS patient, another screen was also applied: his doctors searched for donors whose cells were also resistant to HIV infection.

In order to infect a white blood cell, HIV must latch onto 2 receptors on the cell’s surface: the cd4 receptor and the CCR5 receptor. Some people have no CCR5 receptors due to mutations in the genes encoding the protein—those people are highly resistant to HIV infection. The AIDS patient received bone marrow from a donor whose HSCs (and subsequent white blood cells) could not produce the CCR5 receptor: his new cells cannot be infected by the HIV that decimated his old cells. The AIDS patient was, rather ironically, cured by receiving “defective” cells. The absence of a CCR5 receptor does not appear to affect normal physiology.

Bone marrow transplants are, unfortunately, not a feasible treatment option for the 33.4 million people infected with HIV worldwide. Patients receiving the transplant are at major risk for infection as they wait for their immune systems to regenerate: between 10 and 30% of patients die from the procedure. In addition, there are very few HIV resistant donors relative to the number of infected individuals. On average, 1 of every 1,000 Europeans carries 2 copies of the defective gene while the mutation (a 32 base pair deletion) is very rare in people of Asian and African descent.

The tidings are not all together grim, however. This case shows that HIV can be treated by inhibiting CCR5 expression. If a patient’s HSC could be removed, rehabilitated via gene therapy, and returned to the patient, future AIDS treatment might not require life-long drug courses or dangerous transplants.

At the time of writing this, the GMA website, which usually posts follow-ups, has nothing on their site, which I found a little strange. The mother also appeared not with another member of her family, but a lawyer, who was also a family friend. I wondered how these unusual, but small anomalies reflected on modern society’s schizoid views on drugs. I certainly do not approve of “drugs”, the term which brings to mind things like cocaine, methamphetamine, or marijuana. It should also however bring to mind things like coffee, chocolate, and aspirin. Marijuana is a Schedule I drug in the U.S., which, according to definition, means it has no medical use. This is interesting since there has recently been quite an effort to promote so-called medical marijuana. So really our question should be what is a medicine?

In theory a reasonable definition might have medicine as being some sort of foreign substance that effects treatment of disease. Autism is certainly a disease, but is there any evidence that marijuana can “cure” autism? Without doing any research, we should already be skeptical that the answer could possibly be yes.

For one thing, autism is really a spectrum disorder. That means that there may be many causes, both genetic and environmental that produce the constellation of symptoms we call autism. If a doctor were treating you for cancer, he would first have to know whether it was brain cancer or skin cancer to choose a proper treatment. There are certainly anecdotal sources like this GMA news story, but also other places on the Internet that will tell you that someone has cured their child with marijuana brownies, but do you really know that that child was diagnosed with autism? How can a parent know if the supposedly cured child has the same etiology (same cause of the disease) as their own child? Marijuana, or at least its active component, THC, certainly has a psychotropic affect, as it interacts with cannabinoid receptors in the brain. Can this mean that somewhere somehow marijuana can have some unrecognized benefits for autistic individuals? At this time, there simply is insufficient information to come to a conclusion.

You can certainly understand the desperation of any parent who wanted to get the best treatment possible for their child. While the American Pediatric Society continues to oppose medical marijuana, they are in favor of at further investigation into its applications as a drug. Until then, even so-called medical marijuana is still illegal under federal and most state laws. Hopefully however, if a clinical application for autism is found, stigmas about the idea of marijuana as a “drug,” will not hinder scientific debate and progress.