Comment by pdabbadabba | Hacker News Reader

Comment by pdabbadabba | Hacker News Reader

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> Suddenly the misery of allergies took on a new look. Allergies weren’t the body going haywire; they were the body’s strategy for getting rid of the allergens.

Well of course. I'm just a layman when it comes to allergies, but I thought it was well understood that allergies were the body's inflammatory reaction to an allergen, i.e., an attempt to eliminate (or otherwise neutralize) the allergen. The problem is that, according to the conventional wisdom, the body's reaction to allergen is mistaken. Presumably the body is attempting to target and eliminate something that is actually harmful, but it winds up responding to something harmless, or by triggering a response so severe that it does more harm than good. That's, broadly speaking, the difference between an allergen and a pathogen/poison. A poison/pathogen will actually harm you if it is not eliminated. An allergen will not (or, at least, not in proportion to the severity of the reaction. But I don't see why the observation above has anything to say about the real question, which is why does the body sometimes mistakes one for the other, and freaks out in the presence of harmless substances?

It's not an inflammatory response, it's an immune response. The inflammation is simply a side effect of the immune system swinging into action.

I have theorized that allergies, such as cat allergies, may, in some cases, be your body's way of warning you that there are Big Cats in the vicinity and you should GTFO.

This is not how Type I hypersensitivity works. Epitope recognition is powered by a biological RNG (somatic hypermutation) and evolves at runtime via the process of somatic / V(D)J chain recombination. Your body learns to be allergic, perhaps due to a bad ashy vent (you got sick that one spring), under-stimulation (play outside!), or just plain bad luck. Unfortunately for all of us, the immune system has no concept of the innocuous nature of harmless antigens. It will continue to pick up bad habits until the day we die. But thankfully it also keeps the trillions of cells, leaky programming, our own broken and errant self, and other uninvited guests that would just as soon eat us at bay (bacteria, viruses, cancer, fungi, nematodes, ...).

Did you just say that allergies are never genetic?

No. I described at a high level just one of the mechanisms of adaptive immunity--one of the most incredible biological systems in my opinion. (Runtime metaheuristics search!) These are complex pathways that involve many genes.

If the system isn't working you probably won't live very long. And while there may be certain functional alleles that may increase odds of an initial false positive stimulation, by in large the entire class of failure known as "allergic reactions" is simply a result of how the system itself works. You don't really need to invoke genetic differences to see how it fails. This is why the hygiene hypothesis is so strong.

There are actually four major categories of hypersensitivity that involve different cell populations and signalling pathways (eg. why poison ivy allergy is different from pine allergy).

If you're interested, the Wikipedia articles aren't a bad read. I also recommend Janeway's Immunobiology as a great intro to the entire subject.

Are "autoimmune disorders" another label for a class of failures of this search and respond system?

Loudly sneezing, blurring your vision, and ruining your sense of smell are really not conducive to surviving an encounter with a big cat.

I mean, you might piss it off if you sneeze on it, I guess. Yay?

It's an environmental allergy, not an emergency one. If you notice you feel like crap in a certain place (because cats like to lurk there), and subsequently avoid it, that's a win.

Not that I necessarily believe that's a good explanation for allergies, but it's plausible enough to think about.

Costs vs benefits.

When plants are stressed by bruising from machines, poor storage after harvest, poor soil, or various pesticide/fungicide exposures, they produce defensive toxins, for examples chitinase and solanine. These various chemicals trigger reactions when humans consume the plants. There's a credible argument that the increased "intensity" of modern agriculture has resulted in stressed plants dominating the modern food supply. This is very easy to see if you buy fresh potatoes. The ones that have been cut up a bit by the harvester often smell weird, taste bad, and can even be a bit green with solanine production. You'll find it's typically much harder to get good potatoes in March and April as the ones on sale have been in cold storage a long time and are stressed.

I think peanuts as a crop have suffered from very intensive industrialization more than other crops. Also, I have read that the storage facilities have problems with mold growth. Many peanut butters test positive for mold toxins.

With many of these food allergies where people wonder why it seems to be a modern phenomenon can probably be linked to the degradation of the industrialized food supply.

Furthermore, the ongoing stress of slightly toxin loaded food primes the immune system to over-reactivatity. Things like pollen allergies are aggravated.

Under this proposal, would the prediction be that someone who has a "peanut butter allergy" could eat peanut butter made under special conditions (cleanroomesque greenhouse environment, lots of TLC to the plants, and with screening to ensure that no molds were impacting the final product) without having the reaction?

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