INTRODUCTION
Human being is a unique existence or being or creature. Its uniqueness lies in the unit of legacy called DNA (deoxy ribonucleic acid),present in all the body cells and is the premise of inconstancy among people. The substance structure of everybody's DNA is the same. The main distinction between individuals or any creature is the request of the concoction parts of DNA known as "base pairs" which comprises of four mixes, adenine,guanine, cytosine and thymine. Albeit 99% of all DNAin each human body are the same, the rest of the 1% is one of a kind to every person. On this premise, distinguishing proof of each individual is made conceivable through the utilization of blood assemble framework and DNA fingerprinting. The RBC is produced in the bone marrow by a process called hematopoiesis.
BLOOD GROUP SYSTEM
Blood group is a characteristic of an individuals red blood cell(RBC), defined in terms of specific substances on the surface of the cell called antigen. Which antigen is present on the surface of the blood cells depends on its DNAand this is defined by the source DNA (i.e the parents).
Blood group system is a method of classifying the different blood types in humans.
The two most important classification are ABO and the Rhesus factor(Rh factor). There are 46 other known types in humans, most of which are rarer than ABO and Rh factor.
THE 'ABO' SYSTEM
This system is classified into four groups,A,B,AB and O. However this classification is based on the presence of specific molecules, called antigen on the surface of RBCs. The RBC of these groups contain the corresponding antigens,A,B,A and B,neither A nor B respectively. The blood also contain antibodies as defence against non matching antigens; anti-A and anti-B.
Blood Group A: This group contains antigen A in their blood cells and antibody B in their plasma. People with blood group A can give and receive blood from people with blood group A only (provided they are compatible for Rh factor).
Blood group B:This group contains antigen B and antibody A in their plasma.people with this blood group can receive and give blood to people belonging go blood group B depending on the Rh factor.
Blood Group AB:This group contains both antigen A and B and no antibodies. People with this blood group are known as "universal recipients" as they can receive blood from any blood group based on the compatibility with Rh factor.
Blood Group O:This group contains no antigen but contains both antibodies A and B in their blood plasma. People with this blood group are known as "universal donor" as they can donate their blood to a person belonging to any of the 'ABO' blood group based on the compatibility with Rh factor.
The 'O' blood type is the most common blood type in the world, although in Sweden and Norway, the 'A' group dominates. The 'AB' group is the rarestof the ABO blood types
The Rhesus Blood Group
Like the ABO system, rhesus blood grouping is also classified based on the RBC surface antigen designated by the letters Cc,Dd,Ee and Ff. The letters denote allelomorphic genes which are present in all cells except the sex cells where a chromosome can carry C or c but not both. The Rhesus genes and blood are derived equally from both parents. When the cells contain only 'cde' group, then the blood is said to be Rhesus negative (Rh -ve); when the cells contain C,D or E singly or in combination with cde, then the blood is Rhesus positive (Rh +ve).
These groups are antigenic and produce corresponding antibody in the serum. The antibodies are used to detect presence of Rh groups in blood. Compatibility of Rh factor is very important as mismatching (Rh +ve to Rh -ve) may cause formation of antibody which could lead to hemolysis .
Rh diseases occur when an Rh positive mother gets transfused with Rh negative blood and she then gets pregnant with Rh negative child during her second birth, the mothers immune system is then sensitises against Rh negative RBC. During the pregnancy of the second Rh negative child the body produces an antibody (immunoglobulin G) which can pass through the placenta and heamolyse the red cells of the red cells, thereby causing stillbirth or death of mother or death of both mother and child. This occurrence can b treated with Rhogam (anti-D).
An Austrian scientist, Karl Landsteiner made a discovery of both the ABO system and Rhesus factor in 1901 and 1937 respectively. He was awarded the Nobel Prize in Physiology or Medicine in 1930. The Rhesus system was named after the Rhesus monkey with the help of Weiner.
USES OF ABO AND RHESUS BLOOD GROUPS
•Blood transfusion
•Organ transplant
•Paternity testing
•Treatment of diseases.
