GOLDEN BLOOD: Rarest type of blood in the world

Dr. BHASKAR CHAKRABORTY

We all know the importance of blood in our body and its functions. Blood is a specialized body fluid. It has four main components: plasma, red blood cells, white blood cells, and platelets. Blood has many different functions which includes transporting oxygen and nutrients to the lungs and tissues. The red blood cell's main function is to carry oxygen from the lungs and deliver it throughout our body. Red blood cells also transport waste such as carbon dioxide back to our lungs to be exhaled. Red blood cells can carry oxygen due to a protein called haemoglobin. White blood cells protect your body against infection. As your white blood cells travel through your bloodstream and tissues, they locate the site of an infection and act as an army general to notify other white blood cells of their location to help defend your body from an attack of an unknown organism. The common blood groups we have are: A+/A-; B+/B-; O+/O-; AB+/AB-. Each blood group can be RhD-positive or RhD-negative, resulting in a total of eight blood groups. Blood transfusion these days is only done after blood typing. Hence, people with certain blood groups can only donate to and receive from specific blood groups.

In January 2022, scientists discovered a "Rarest Blood" and they coined the term as "Golden Blood". Though scientists couldn't identify and exactly how to differentiate this "special blood group" from the conventional one's when identified first in 1961 in an Australian woman but in 2022 they could differentiate and gave the terminology for this blood group as "Golden Blood". After an exhaustive study and research scientists have found that fewer than 50 people (probably 43) worldwide have "Golden blood" which is also known as "Rh-null". Blood is considered Rh-null if it lacks all of the 61 possible "Antigens" in the Rh system. It is also very dangerous to live with this blood type, as so few people have it in the world.

This blood is excellent for transfusion because it lacks common antigens, and it can be accepted by anyone who needs a transfusion without the risk of a blood transfusion reaction. However, due to its rarity, it gets extremely difficult to find this type.

This is rarest blood was first seen in Aboriginal Australians. The first case of "Golden blood" was identified in 1961 in a woman born in Australia. Since then dozens of other strange cases have been found in the world and scientists estimate that around 1 in 6 million people worldwide have this blood type. The first case of "Golden Blood" group was found in India is in Gujarat when a 65 year man who had a cardiac attack and was admitted for surgery on 14 July 2022. The worry with the golden blood group is that the donations of Rh null are incredibly scarce and difficult to obtain. An Rh null person must rely on the cooperation of a small network of regular Rh null donors around the world if they need the blood. Across the globe, there are only nine active donors for this blood group. This makes it the world’s most precious blood type, hence the name "Golden blood".

Our red blood cells have proteins called antigens on their surface. Depending on the antigen the blood group system has a further distinction as "Rh-positive" or "Rh-negative" depending on the presence or absence of the "Rh-D" factor in the cells. With the golden blood group, a person lacks all the Rh antigens whereas a person with the Rh-negative blood group lacks only RhD antigen.

The golden blood group seems to be a result of genetic mutation (spontaneous change in a gene). It is commonly seen with mutations in the "RHAG gene". RHAG gene is  Rh-associated glycoprotein which is ammonia transporter protein in humans. RHAG has also recently been designated CD241 (cluster of differentiation 241). Mutations in the RHAG gene can cause stomatocytosis which codes the Rh-associated glycoprotein. This protein is required for directing the Rh antigens to the RBC membrane.

RHAG mutation is often associated with a disease called "Hereditary stomatocytosis". These individuals can have long-term, mild, hemolytic anemia and increased RBC breakdown. The Rh-null phenotype can also be seen in the case of certain anemias a person may be born with.

The following conditions may put you at a higher risk of the "Golden blood group":

a) Consanguineous marriage (marriage between cousins, brother-sister, or anybody who is a near or distant relative)

b) Autosomal genes (abnormal genes, which have disease traits, passed down through families)

c) Changes or complete deletion of certain genes, which are RHD and RHCE or RHAG.

"Golden blood" can be donated. Because of the absence of antigens on RBC's, a person with Rh null blood is considered to be a universal donor and this blood can be donated to anyone with rare blood types within the Rh systems.

This blood is excellent for transfusion because it lacks common antigens, and it can be accepted by anyone who needs a transfusion without the risk of a blood transfusion reaction. However, due to its rarity, it gets extremely difficult to find this type. Conversely, Rh null is usually not so good for the people who have it. If they ever require a blood transfusion, receiving any blood that does have the Rh antigen may inevitably cause a transfusion reaction.

People with "Rh null" or "Golden blood" type may have mild to moderate hemolytic anemia since birth. This leads to faster destruction of RBC's, which may cause low haemoglobin levels and lead to paleness and weariness. This occurs due to structural defects in RBC's like "Mouth-like" or "Slit-like" shapeless elastic structure of red cells with abnormal red cell covering!

Increased fragility due to the lack of Rh antigen may alter blood cell volume. People with "Golden Blood" may face blood transfusion challenges if the person’s blood is exposed to Rh antigens (proteins on the surface of RBC) from the other person’s blood, they readily form corresponding auto antibodies and there may be a severe transfusion reaction. Therefore, for these types of patients, hospitals need to have special protocols in place and quick response management.

Rh incompatibility during pregnancy is a matter of concern. If the mother is Rh null and the baby is Rh-positive and if the mother’s blood gets sensitized by the baby’s positive blood, then the mother’s blood may produce protective proteins called antibodies that could target future pregnancies or lead to abortion or miscarriage.

Several studies conducted very recently (October 2023) have found that an "Infection" or "Sepsis" in such individuals (having Rh-null or golden blood) may precipitate massive haemolysis, subsequent kidney failure and other complications which ultimately leads to death.

Email: bhaskargtk@yahoo.com