Allergies/autoimmunity

On Thursday, I had a post published on Scientific American's guest Blog about claims that genetically modified food crops could contain allergens. In it, I am critical of the Union of Concerned Scientists (a science advocacy and policy organization), for what I read as misplaced opposition to genetic engineering: The UCS’s concern about the dire state of our food system is well-founded, and I applaud their efforts to get out in front of the policy debate. There’s just one problem: they oppose using all of our technology to help combat this problem. Specifically, I’m talking about genetic…

Every time I see an ad for some remedy that "Helps BOOST the Immune System!"  I die a little inside. It's not just that these products are often homeopathic bull*, but (as I've mentioned before), boosting the immune system can actually be a terrible idea. The immune system is a finely tuned instrument, and too much can be just as bad too little. Too much immune activation leads to allergies and autoimmune disorders like multiple sclerosis (MS) or lupus. We don't know exactly why, but the prevalence of  these "hyperinflammtory disorders," where the immune system is over-active, are on the rise…

The vast majority of funding for biological research in the US comes from the National Institutes of Health (NIH), and as a result, most of our grants are written in a way that plays up the clinical importance of our work. Some variant of the phrase, This research has implications in the treatment/prevention of [insert disease here]... appears in just about every grant and research paper in my field. In truth, it's often very difficult to draw a direct line between a specific research project and a drug that your doctor can prescribe. We like to pretend that we can leverage research to…

In honor of the great Scienceblogs migration, and inspired by Ethan's wonderful post about the migration of the universe, I thought I would talk about something on a smaller scale: cell migration. The scale is small, but the problem is huge. Most of your organs are locked in place - your heart never needs to be in your thigh - but the immune system has to be everywhere. When you cut your toe, breathe a virus into your lungs or eat a piece of contaminated spinach, the immune system needs to be johnny-on-the-spot with the inflammatory response. Thankfully, there's already an organ system that…

At the risk of seeming like a one-trick pony, and piggybacking on my recent appearance on the Savage Lovecast, I thought I would close the loop on immune reactions to semen. I've already written about allergens being transmitted in semen, and about women having allergies to seminal plasma itself. In the latter case, I say women having allergies not only because the only examples I found were in women, but also because by definition men cannot have allergic reactions to semen. In response to a comment on that post I wrote: If a man did get an immune response, it would probably be called "…

In case anyone landed here after listening to this week's Savage Lovecast, I wanted to point you in the right direction. Please be gentle - that was my first time being interviewed for anything like that, so I was a bit of a nervous wreck. For the uninitiated - a couple of weeks ago on his podcast, Dan Savage fielded a question from a woman that thought a chunk of mushroom managed to make it through her boyfriend's digestive tract untouched and end up in his ejaculate. Dan rightly dismissed this notion, saying that things don't go "from guts to nuts." This is certainly true for solid pieces…

I know this post has been a long time coming. In the first part of this series, I told you that allergies are the result of an immune response against an external, but normally not harmful substance. In part 2, I told you that allergies are the result of a specific type of immune response called "Th2," which leads to the production of IgE antibodies, and that this immune response is thought to have evolved to combat infections caused by worms. But what makes your immune system think it's supposed to be battling a worm? The short answer to the questions is: we don't know. For other types of…

Earlier this week, I wrote a little bit about what causes allergic symptoms - your immune system confuses pollen (or some other allergen) for a worm, and then arms your granulocytic grenades to explode every time you come into contact with it. But why does this confusion happen? This is a bit more complicated. As I mentioned in the first post, the immune system broadly speaking is geared for 3 types of infections: 1) Intracellular - these pathogens (all viruses and some bacteria like Listeria) live most or all of their life inside our own cells. In order to deal with them, the immune system…

One of my favorite places on the internet is r/askscience, a place on reddit where people come and ask questions, and a panel of scientists answer. People can ask follow-up questions, and there is often some great back-and forth (to be honest, part of the reason I haven't been writing as much here is because I'm using up all my time over there). Recently, an number of people have been asking questions about allergies - Can people grow out of allergies? Why is the incidence of allergies increasing? Can eating honey cure allergies? You can check out those threads if you want answers to those…

While researching Wednesday's post, I ran into a number of strange case studies. They didn't quite fit into that post, but I thought they were too interesting to ignore. If you're interested, follow me down the pubmed rabbit hole. When I typed "semen allergy" into google scholar last week, the very first hit was this paper [pdf]: We report the case of a 20-year-old woman with documented Brazil nut allergy who developed widespread [hives] and mild [shortness of breath] after intercourse with her boyfriend who had earlier consumed Brazil nuts. Skin prick testing with the boyfriend's semen…

For about two years in high school, I would occasionally break out into pretty severe hives. I would first notice a mild itch on my wrists or ankles, and I would know that the hives were coming if I gently scratched my forearm and raised red streaks were left behind (I have a picture somewhere of a large inflamed smiley face I drew on my chest during one of these episodes). A dose or two fo Benedryl would completely knock the hives down, but left untreated, they would spread over my entire body. It was almost certainly an allergic reaction, but despite a battery of tests at an allergist's…

Antibodies are often thought of as magic bullets, and as far as bullets go, they are about as magic as you can get. Antibodies are proteins that are manufactured by specialized "B-cells," and their main feature is that they stick to things. At first glance, biochemical stickiness does not seem all that magical; there are innumerable examples of proteins that have evolved to interact with one another or with other types of molecules. But while natural selection can take millions of years to refine an interaction, your body can mount an immune response and generate antibodies against almost any…

Our immune system needs to be on a hair-trigger. When you breathe in a virus or a bacterium enters a cut on your arm, you don't want to mess around: (disclaimer: most of what George Carlin says in the rest of that clip is not supported by the science (though it's funny as hell)) But all of that heavy immunological artillery is dangerous, and when it's directed at the wrong target, there can be a lot of collateral damage. Some of the most important parts of the immune system are mechanisms of tolerance - teaching the immune system to ignore the things that aren't a threat. For the innate…