by Odia Iyoha

In Dr Chili’s story, the recipient died as a result of Rhesus factor incompatibility on second exposure to the Rhesus D antigen. Abass was B Rhesus D negative while the donor was B Rhesus D positive. He already had a previous transfusion with a Rhesus D positive blood. On the second exposure to the Rhesus D antigen through the blood Dr Chili transfused him with, the already formed antibodies against Rhesus D antigen attacked the Rhesus D antigens entering his body.

The expired anti D reagent gave a false test result. In spite of Dr Chili’s expertise and dedication to the job, she fumbled so much. She was moved by her human nature to save him, no matter what it took. She knew it was very possible for Abass to be Rhesus factor negative but at that moment, she let ‘what if?’ determine her decision. She thought too that even though he may be Rhesus D negative, a first time isn’t always bad. She also knew that the likelihood of him being Rhesus factor negative was very slim because only about two in every ten persons in the population are Rhesus factor negative and also because during and after her housemanship to the time of her service, she did not encounter any Rhesus factor negative patient. It was only twice during her clinical postings as a Student that she came across two pregnant women who were Rhesus factor negative. Dr Chili probably acted on impulse and the fact that she takes the Hippocratic Oath to heart pushed her further to save the patient no matter what. If she had taken her time to think it through, she would not have gone ahead with the transfusion. Who knows? He may not have died if he wasn’t transfused at all.

******************************

The Rhesus Angle

Rhesus factor (Rhesus D) compatibility test is an important blood grouping test that has to be done along with other blood grouping before blood can be transfused from a donor to a recipient. It is very important to know your Rhesus factor group. There are two groups, positive (usually denoted with +) and negative (usually represented with -).

Firstly, when blood is to be transfused, the blood grouping tests are carried out to ascertain if the recipient can receive blood from the donor. The donor’s blood is also tested to make sure it is free of any infection.

Blood groups are determined by the genes we inherit from our parents and they can be identified by antibodies and antigens in the blood.

Antibodies are proteins found in the plasma as part of the body’s natural defence system providing immunity. They recognize foreign substances and alert the immune system which fights and destroys them. Antigens are also protein molecules but they are found on the surface of red blood cells.

Blood groups are mainly A, B, AB or O. There are other types however but the ABO blood grouping is the most common. If a recipient has blood group A for example and the donor has blood group B, transfusion cannot take place because of the mismatch. But if the donor and recipient have the same blood group, transfusion can only take place after another type of blood grouping has been done to determine their compatibility. This other blood grouping is known as the Rhesus factor. The Rhesus D antigen may or may not be present on the red blood cells.

If it is present in a person’s red blood cells, the person’s Rhesus blood group is Rhesus D positive. If it is absent in a person’s red blood cells, the blood group is Rhesus D negative.

In blood transfusion, only the recipient’s antibody and the donor’s antigen are considered and not the other way round. This is because the recipient’s antigen will produce antibodies against an antigen that it does not contain and cause a reaction -agglutination, so it is only important to note the recipients antibody and the donor’s antigen so that there will be no agglutination reaction in the recipient’s body if given the wrong blood. If the recipient’s antibody matches the donor’s antigen, agglutination cannot occur.

The Rhesus factor is not naturally occurring, hence the body doesn’t have preformed antibodies against the Rhesus D antigen unlike the ABO blood grouping that have preformed antibodies against the antigen that it does not have. A person can only develop antibodies against the Rhesus factor if it has been sensitized – sensitization only happens in a Rhesus D negative individual. A Rhesus D positive individual does not have antibodies against Rhesus D and can not develop antibodies against it.

What do I mean? Usually, if a person is Rhesus D positive, he has no worries. But if a person is Rhesus D negative, he should be alert but not agitated. If he is transfused with Rhesus D positive blood the first time, his body recognises the Rhesus D as a foreign agent and becomes sensitized to it and develops antibodies against the Rhesus D. The body knows that it is not present in its body so it becomes aware of it.

On a second transfusion with Rhesus D positive blood, the body’s now formed antibodies against Rhesus D recognizes the Rhesus D antigen (foreigner) and attacks it. This second exposure and the body’s reaction/attack will cause the blood cells to agglutinate in the transfused patient and will cause rapid destruction of red blood cells. It can be fatal if transfusion is not immediately stopped.

This is what happened to Abass. The blood he received from St Michaels Hospital was B Rhesus D positive and his body already formed antibodies against Rhesus D antigen after the first exposure. On his second exposure at the clinic where Doctor Chilli transfused him, the already formed antibodies attacked the Rhesus D antigens of the donor and this led to a reaction in his body which was fatal.

The Doctor who transfused him at St. Michaels probably had the same thoughts as Dr Chilli – Nothing would happen with the first transfusion even as the Rhesus D of the patient and donor do not match. When the Doctor noticed at St. Michaels hospital that Abass had been transfused with the wrong blood, it was kept under wraps in other not to receive query from his superior Colleagues. The Doctor also hoped just like Dr Chilli that Abass would never get to be transfused with a Rhesus D positive blood again in his lifetime but unlike Dr Chilli who kept it at the back of her mind to inform Abass, the Doctor at St. Michaels never informed Abass.

Agglutination = blood clumping.

Note that individuals with Blood group:

1). A have Antigen A on their Red blood cells and produce Antibodies against Antigen B.

2). B have Antigen B and produce antibodies against Antigen A.

3). AB have Antigens A and B on their red blood cells. They have NO antibodies.

4). O have NO antigens. They have Antibodies A and B.

Bearing in mind that in blood transfusion, only the recipient’s antibodies and the donor’s antigens are considered, note that Individuals with:

1. Blood group A can donate blood to individuals with blood groups A and AB and receive blood from blood group A and O.
2. Blood group B can donate blood to individuals with blood groups B and AB and receive blood from individuals with blood group B and O.
3. Blood group AB can donate blood to individuals with blood group AB only and receive blood from blood groups A, B, AB and O because they don’t produce any antibodies against any antigens as they have both antigens A and B, hence are termed Universal recipients.
4. Blood group O can only RECEIVE blood from group O individuals because they have antibodies A and B. However, they can DONATE blood to individuals with Blood groups A, B, AB and O because they have NO antigens, hence the recipient’s antibodies won’t be able to react against any antigen.  This is why they are called Universal donors.

If a recipient and a donor have the same blood type and Rhesus factor, transfusion can take place. If in an emergency situation that involves several recipients, only blood group O Rhesus D negative blood are available, the recipients can be transfused with the blood whether or not the recipient’s blood groups are known because O Rhesus D negative blood group is the ultimate universal donor as it does not contain any antigen (A or B) or Rhesus factor. O Rhesus D positive blood group is also a universal donor but not absolute as it can only be given to all those blood groups with Rhesus D present, that is A+, B+, AB+ and O+. O Rhesus D positive blood group does not have any antigen present on its red blood cells but it has Rhesus D factor present.

The following instances would not have led to Abass’ death:

1. If despite the lapses, the donor was O Rhesus D negative.
2. If Abass was B Rhesus D positive, just as the donor.
3. If the donor was B Rhesus D negative, just as Abass.
4. If on the other hand, the donor was B Rhesus D negative while Abass, the recipient was B Rhesus D positive.

In Rhesus factor blood grouping, Rhesus D negative persons can donate blood to Rhesus D positive persons of the corresponding blood type (A- to A+ or B- to B+ or AB- to AB+ or O- to all blood types: A-, A+, B-, B+, AB-, AB+, O-, O+) but not vice versa for the same reason that Rh D factor is absent in Rh D negative blood and cannot elicit a reaction if given to a Rh D positive person but Rh D factor is present in a Rh D positive person and will elicit a reaction if given to a Rh D negative person.

There you have it, knowing your Rhesus D blood group is as important as your identity. It is very compulsory that you know whether you are Rh D positive or Rh D negative. Knowing you have A, B, AB or O blood group alone is not enough. You need to know more; it is very pertinent for you to know everything about your blood grouping – type and Rh D factor.

You may find yourself in emergency situations that involve life and death where the only delay in saving a life will be because you do not know everything about your blood group.

The simple way to understand all I have written is this:

Consider your body as a house that has security systems (soldiers) that are only activated when there is an intruder/invader inside your house. Now, the rule is, if your house already has the type of intruder coming in, there will be no activation of the soldiers but if your house doesn’t have the type of intruder coming in, the soldiers will be activated the first time and by the second intrusion, they will attack and kill the intruder to prevent it from staying in your house. The only type of foreigner allowed to enter your house because it will not destroy your house is the negative Rh D factor of corresponding blood group. This is because unlike other intruders, this one is coming in harmless, no weapon. Its presence will only affect you if you don’t have Rh D factor and the foreigner has it. In this case, the soldiers in your house will be activated against it.

Note that I didn’t write ‘entering’, instead, I wrote staying because when an antigen produces antibodies against an antigen that it does not contain, all the reactions that happen takes place in the recipient’s body and not outside. So the job of the soldier only starts after the invader has gained entry, not before. In the shootings and combats that will happen afterwards, your house will definitely be destroyed. Even though not every part of your house will be affected, the severe damage caused to some parts of your house will affect your whole house. This is how the blood groupings work.

Your house is your red blood cells, the Soldiers are the antibodies produced in response to foreign particles/agents, the intruder is the antigen or Rh D factor that your red blood cells may not contain, the shooting and combats inside your house are the agglutination reactions that occur inside your blood vessels after the entry of foreign agents.

I hope this charges those of us who don’t yet know our blood groups and Rh D factor to go for revealing tests as soon as possible. I am A Rhesus D positive, it means I can donate blood to individuals with blood group A Rh D +ve and receive blood from individuals with blood group A Rh D +ve, A Rh D -ve and O Rh D +ve and O Rh D –ve. (Remember I can receive Rh D negative corresponding blood even as I am positive because the incoming blood has no intruder attached to it so why should my body fight it? But if I were A Rh D -ve, I won’t be able to receive blood from A Rh D +ve or O Rh D +ve because my body will fight the intruding Rh D +ve factor coming in.)

MORE IMPORTANTLY, if you are a woman and you are planning to have your biological children, know your Rh D factor so you won’t be sorry later. I will shed more light on this in the second story on Blood grouping. Until then, have fun!

Op–ed pieces and contributions are the opinions of the writers only and do not represent the opinions of Y!/YNaija

Tales from the grave is a medical series on the potential killer Rhesus Factor Incompatibility

Op-ed Editor