Antigens and Antibodies

For the less technical amongst us – and I regard myself as one of those – the wonders of Blood Grouping can be a bit of a blur of bio-babble. We may have heard of Anti-A and Anti-B, we may know what a reagent is or what it does, but we might not be aware of the broader picture.

Since working for Lorne, I have been fascinated about my blood group profile. I have longed to find out, but I wasn’t sure where to start. I had asked my doctor on my last visit to the surgery what my medical records could tell me, but there was no record that my blood group profile had ever been determined. It is not so surprising – I have never had surgery in which a blood transfusion was likely, so I have never been tested.

I thought that I might have found out when I signed up to donate blood. However, I was turned down due to a mild medical complaint in the past and so I never even got to find out my ABO blood group. So, when I was given the chance to find out my blood group profile, I jumped at the chance.

And now I have the results. I am A negative, B negative and D positive (which makes me O positive). I am Cellano positive, M positive, N positive and S positive. And so the list goes on. I am positive for P1, Lub, Leb, Fya, Fyb, Jka, and Jkb. But what does it mean to be positive for these? What exactly is positive?

It turns out that my red blood cells have little protein and sugar structures on their surface that biologists call ‘antigens’. These antigens can bind with antibodies that are present in my blood serum. Being O positive means that I lack the A antigen and the B antigen, but I do have the D antigen present on my cells. Conversely, it means that my Anti-A antibodies and my Anti-B antibodies are still floating around in my blood serum. They have no corresponding antigens on my red blood cells to bind to.

I do have the D antigen. I also have all the antigens that I listed before. For all these antigens, the corresponding antibodies are bound to my red blood cells. For all the other absent antigens (for which I am negative), the corresponding antibodies are still to be found in my blood serum.

So, that’s how it works. Now I know. I cannot wait until the next time a nurse or a doctor asks me if I know my blood group. I look forward to watching their face as I start the list. “I believe I am O positive”, I will say, before taking a deep breath and continuing, “cellano positive, Kell negative, Kpa negative, Kpb positive, M positive…”