Most Common Blood Type?

You can figure this out on Google in .20 seconds. I know. I did it. It’s O+.

The fact that I searched for this begs the question…why? Shouldn’t I know this?

*ahem*…blush. Pretty much, yeah. I should know it and in fact once I read it, I remembered that I knew it. Can I prove that? Nope. But once upon a time – according to me – I really did know that without Google’s help.

What I DO still know is what blood type O+ means. The O signifies one of 4 major blood groups: A, B, AB and O. What does it mean to be one type or another? Really it’s a description of the type of protein on the exterior of human red blood cells. Imagine a smooth, red balloon. Smooooooooth. Ok. Got it? That’s NOT how it looks.

First, imagine pushing into the balloon with both fists at equal points from each other (as in, the north end and the south end) to the point where both fists are almost touching through the balloon. Now you have a better idea of the shape of a blood cell (if you haven’t noticed the HUGE red picture next door). Now imagine buh-jillions of antennas, scaffolding and twisted metal extending from the surface of the balloon. THAT’S what it looks like. You just don’t see them because they’re small and most pics (again, next door) don’t show them.

Of those things sticking out of the balloon, the most important are these two big ones…aptly named A and B. Think of it like the city of Paris – lots of buildings everywhere – with a big Eieffel Tower sticking up higher than all of them. Some balloons have one tower (A). Some have a different one (B). Some have both (AB). Then there’s one that doesn’t have any, which is called O just for fun.

There’s another important thing sticking out of the cell. It’s either there or it isn’t. If it’s there, you’re +. If not, you’re -.

A little-known fact is that there’s all those other proteins (buildings in Paris, if you’re still traipsing through the analogy) that only sorta matter to practical health issues. The fact is that your immune system gets REALLY annoyed at the A’s, B’s and +’s if it’s never seen them before. It doesn’t care about the other “buildings” – they may cause a fever or turn your pee dark for a few days. But if you get blood cells that have A, B, or + antenne on them, your immune system will attack them, kill them, and make you really sick. It’s can be especially tragic if it happens in a baby. But the other buildings don’t really matter to anyone but PhD’s. There’s all kinds of them, all with names and designations that nobody cares about (although there is one protein called the “Lutheran” protein which, in my opinion, puts a whole new spin on the predestination thing).

So the most common blood type is O+. People who have O+ have immune systems that don’t like blood with A, B or AB proteins. However, they don’t care if that blood is + or -. So, if you your goal in life is to donate blood, you want to have blood type O-. This type of blood is the Switzerland of red blood cells. Everybody gets along with it because it has no important proteins to attack. If, on the other hand, you spend most of your time in high-velocity situations and the potential for massive blood loss is looming in your future, you’d like to be of type AB+. This means your immune system has seen it all – the Moll Flanders of immune systems (been around the block, if you will). O- is therefore the “Universal Donor”, meaning it is appropriate for Klingons, Wookies and all Earthlings. AB+ is the “Universal Recipient”, meaning they can take blood from all the people that the Universal Donor just gave to.

Finally, I just learned from the pediatric cancer docs that you can completely change a person’s blood type by irradiating their bone marrow until it’s all dead, then transplanting from a donor with a different blood type. Thus, if you want to commune with the universe, consider one of these two blood types. Otherwise, you’re just boring and complicated like the rest of us.

A.L.L.

Spent the morning with pediatric hematologists. Basically their days are spent dealing with sickle-cell anemia and leukemia. Of the blood cancers, the most common is acute lymphocytic leukemia, e.g. ALL.

There was this really smart woman in my med school class who was determined to be a pediatric oncologist. I thought she was crazy. I still do. One of the kids we saw today woke up a few months ago with headaches and some vomiting. Turns out he had a tumor in the back of his brain. They also found it had metastasized down his spinal column and had at some point also settled in one of his hips. The original cancer was found to be from a form of lung cancer that adults usually get from smoking (non-small cell carcinoma).

“Not good,” the kind, crusty oncologist said after he described the basics of the case to me. Of all the people in the world you don’t want to hear ‘not good’ from, I’d put a pediatric oncologist right up there with pilots and exterminators.

An interesting thing I learned about ALL: It has always been the bellweather of pediatric cancer therapy because for decades it has been both the most common leukemia, and the one with the best prognosis. 30 years ago the survival rate was only about 60% (and that was considered good back then). Now it’s over 90% if all the risk factors are minimal. In the 1970’s, there was a big jump from 60 to 80% survival. Why? Because one doc in one hospital found that although they were curing ALL, there was lots of relapse in the CNS (brain and spinal cord), so they started irradiating kids’ brains as part of the ALL therapy. Survival went up, dramatically. The CNS is now regarded as a “sanctuary” site for cancer cells and is usually treated when kids get cancer.

Then survival jumped from the 80’s to the 90% range when docs started realizing that the amount of radiation they were giving was waaay too much and was causing brain tumors and other problems. Today, they rarely use radiation as part of ALL therapy, but they do give chemotherapy intrathecally (directly into the spinal column), and survival is generally really good for these kids.

Not so for this extremely cool 10y old boy with the medullary blastoma. He’s not likely to make it much longer. This is probably not a job I could handle. I’d either become a massive jerk or a slobbering emotional mess. It’s a unique person that can deal with these kids every day for years and still maintain a balanced humanity.