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An it from alleles. The absence of

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An individual’s
blood group never changes including reference to specific illnesses and
transplantation

An entire blood group system that
consists of one or more erythrocyte antigens describes the term ‘blood group’, a
series of genes control the specificity, and this can be allelic or linked
close on a single chromosome making it difficult to distinguish it from
alleles.

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The absence of specific antigens
can be the bases of blood separation, consideration of a blood group could be
by any detected variation or polymorphism detected in the blood. However, the
term blood group is usually restricted to blood cells, surface antigens, and
generally to red cell surface antigens. Although detection of polymorphism in
red cell surface proteins is attainable by other methods, for instance DNA sequences analysis,
unless defined by an antibody such variants cannot be titled blood groups. (Daniels,
2014).

The ABO group system has four
main group types that blood groups are divided into: A, B, AB, and O. The genes
inherited from your parents determine this as blood type is inherited by
parents. One of two ABO genes are donated by each biological parent. The A and
B genes are dominant and the O gene is recessive. Antigens and antibodies found
in the blood identify an individual’s blood group. Antibodies are a protein found
within the plasma, they are part of the body’s natural defence mechanism
against invading substances such as germs. When foreign material enters the
body antibodies alert the immune system to destroy it. Whereas antigens are
protein molecules found on the surface of red blood cells. Red cells in the
blood that have type A antigens on the cell surface contain antibodies against type
B red cells in its serum. If type B blood is given to an individual with type A
blood, antibodies in the recipient’s blood will destroy the red cells of the
injected blood. Similarly, type A red cells will be destroyed by anti-A antibodies
in blood type B.

Rhesus (Rh)
blood grouping system splits blood groups in accordance to whether the Rh
antigen (Rh factor) is present or absent on the red blood cells cell membranes.
The most common Rh
antigen is termed RhD, this causes the most severe immune reaction and is the
primary determinant of the Rh trait. In clinical importance Rh is second
to the ABO blood groups (Flegel, 2007).  An individual that lacks the Rh
antigen could be in danger if Rh positive blood is given in transfusion. The
first time Rh incompatible blood is given there may not be effects, however the
response of the immune system is to produce anti Rh antibodies. After the          antibodies form, if Rh positive blood
is given it can cause agglutination as they will attack the foreign red blood
cells. Resulting in
haemolysis, this causes serious illness or can be fatal. 

Different antigens and antibodies
are present in each group within the ABO systems, group O red blood cells have
no antigens therefore, can be used safely for any group types. Red blood cells
can have an additional antigen present, this is known as the RhD antigen, and
each blood group can be RhD positive or RhD negative. This is determined by the
presence of the antigen, if the antigen is present, it is positive and if it is
absent, it is negative.  

Stem cell transplantation of the
bone marrow is a procedure that affects the patient that is receiving the
transplant. In the process the recipient’s marrow is destroyed, if different
red cells are produced by the donor’s marrow, the recipient will produce
different red cells matching the donor’s, as the blood comes from the donors
stem cells.

 Peripheral blood stem cell transplant is
another method, here stem cells are taken from the donor’s blood, resulting in
production of new blood cells. Matching human leukocyte antigens (HLA) is
essential for stem cell transplants, they make up an individual’s tissue type, and
this is different from blood type. This plays a significant role in the success
of the transplant, there are six major HLA antigens, and a match of all six
will result in lower chances of complications such as graft rejection. A study reveals conversion
of RBC phenotype to donor ABO phenotype, resulting in their host derived anti-
donor ABO antibodies to be lost in all major mismatch patients (Esther,
2014).   

Thalassemia is an increase in red
blood cell (RBC) demand, this occurs when one of the genes involved in
haemoglobin production has a mutation, this genetic defect is inherited from
parents. This could weaken the expression of ABO blood group antigens (Dean,
2015). Haemoglobin is a protein molecule that carries oxygen in RBCs, excessive
destruction of RBCs is the result of the condition.

Leukaemia affects the white blood
cells which play an important part in infection fighting in the immune system. Leukaemia
results in abnormal production of immature white blood cells which clog up the
bone marrow stopping production of other blood cells that are required for
healthy blood. Acute leukaemia is a disease that can affect an individual’s
blood group (Anifowoshe et al 2017). Patients with acute myeloid leukaemia who were
reported to have ABO antigen alterations during the phase, upon remission they
re-expressed their original ABO antigen (Rakul et al 2017). It has been said
that in some leukemic patients’ changes of the promoter of ABO genes in RBCs by
leukemic cells leads to its suppression and consequent alternation in the blood
group, this can be identified before diagnoses or to herald leukaemia relapse (Radhakrishnan,
et al 2016). Changes of RBC antigens have been described in association with
haematological malignancies, after resubmission is attained the modifications
of blood group antigens usually revert to normal (Rakul et al 2017).

Liver transplant is required when
an individuals liver is diseased and needs replacing, the donor liver can come
from a living donor or a deceased donor. This is a major surgical process, the
body will always try to destroy the transplanted liver as it is seen as foreign
to the body, resulting in individuals with liver transplants having to take
medication for the rest of their lives. A2 is a sub group for individuals with
blood group A, this group is formed with patients that’s A antigen on their
RBCs has a lower expression, therefore immune mediated haemolysis is less
likely when in contact with serum that contains anti-A antibodies (Mettu, 2013).
There are three possible stages for a liver transplant, stage one (preanhepatic)
the diseased organ is removed, transection of collaterals causes blood loss
developed from portal hypertension. Stage two (anhepatic) starting with implantation
of the donor liver ending with graft reperfusion, this aspect in the procedure
is dangerous as abnormalities can arise such as hemodynamic abnormalities. Stage
three (postreperfusion) starting with reperfusion of the grafted liver, this
creates hepatic arterial anastomosis. For the new liver a form of biliary
drainage is prepared, good surgical hemostasis and closing is obtained. In
matching organs for transplantation, the Rh factor is not usually a significant
consideration, this applies for most centres of matching organs. (Mettu, 2013).
The Rh factor (+ or -) can change as the patient can begin to develop the donors
blood type (Allanki, 2009). REVERSABLE

Non matched transfusion

Transfusion rejection can occur,
to avoid this prior to a blood transfusion two test are required, these are
termed type and cross match. Both donor and recipient must lack the same ABO
and Rh D antigens. The process begins with determining the ABO and Rh D position,
once the type is recognised this allows a blood compatible transfusion to go forward.
However, as the donor’s blood can contain other antigens that are incompatible
to the recipient’s blood another test must be carried out, this is called a
cross match. This ensures that the serum of the recipient and the RBCs of the
donor match (Dean, 2015). The tests include small amounts of the recipient’s
serum and the donors RBCs, examination of the mixture is done under a
microscope. Incompatibility is shown by the donors RBCs agglutinating by antibodies
in the recipient’s serum. 

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