Haematology and Blood Transfusion

Haematology and Blood Transfusion 1
HAEMATOLOGY AND BLOOD TRANSFUSION
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Haematology and Blood Transfusion 2
Section A
Question One
a)
Extramedullary hematopoiesis (EH) involves the formation of blood components in the
peripheral organs. It may occur during the development of embryos or following immunological
responses. More also, extramedullary hematopoiesis may arise on pathological circumstances
secondary to unproductive hematopoiesis; for instance, it may be present in malignancies
associated with hematologic diseases (Zhang et al. 2016). Hematopoietic cell accumulation that
characterizes EH occurs in various body sites such as the spleen, lymph nodes, liver, adrenal
glands, nasopharyngeal regions, and malignant neoplasms. Spleens are the common sites for
extramedullary hematopoiesis; therefore, it provides a different place for assessing the
hematopoietic stem cells (Zhang et al. 2016). During embryonic development, extramedullary
hematopoiesis occurs in the yolk sac or spleen before bone marrows mature. More also, in the
immunological response to pathogens, EH occurs in the liver or spleen to produce antigen-
presenting cells (Crane, Jeffery & Morrison 2017). Besides, EH ensues in certain pathological
situations for instance, when the collagenous connective tissues replace the marrow cells. The
result is an inhabitable marrow for both the stem and progenitor cells (Crane, Jeffery & Morrison
2017).
b)
Acute Lymphoblastic Leukaemia (ALL) is the cancer of the bone marrow in which the
immature lymphoblasts proliferate and substitute the healthy hematopoietic cells (Stephen et al.
2015). It occurs due to abnormal gene expression among individuals with chromosomal
dislocations often resulting in the production of fewer blood cells. More also, lymphoblast

Haematology and Blood Transfusion 3
infiltration causes enlargement of different organs such as the liver, spleen, or the lymphatic
system. Acute Lymphoblastic Leukaemia is more prevalent among children than in adults
(Stephen et al. 2015).
There are several classification systems, and since its inception in 1976, the French-
American- British (FAB) system has classified acute lymphoblastic leukaemia according to
morphology. This system considers information about sizes, cytoplasm, nucleus, basophilia, and
vacuolation, which is the investigation of the various geometrical, chromatic, and textural
elements of the cytoplasm and nuclei (Rawat et al. 2017). FAB classifies ALL into three sub-
types: L1, L2, and L3. According to Mandal (2019), about 31% to 84% of the adult and children
incidents of acute lymphoblastic leukaemia fall in the L1 category. Cells under this category
have regular shapes and with homogenous nuclear chromatins. Besides, they have scanty
cytoplasms, small nucleoli and moderate basophilia (Mandal 2019). The cells in sub-subtype L2
are large and have irregular nuclear shapes. The cells have prominent nucleoli and variable
basophilia. These cells are heterogeneous with variable nuclear chromatins (Terwilliger &
Abdul-Hay 2017). Finally, the cells in sub-type L3 are large and exhibit homogenous chromatin.
These cells have regular nuclei and basophilic cytoplasm. Notably, the distinctive element in
ALL-L3 type is the prominent cytoplasmic vacuolation (Terwilliger & Abdul-Hay 2017).
Question Two
The vital step in the diagnosis of Acute Lymphoblastic Leukaemia (ALL) is the
examination of any physical signs. Hematologists ought to take blood samples from the affected
organs such as the swollen glands. The presence of numerous white blood cells is a hallmark for
ALL. Cooper and Brown (2015) assert that 34%-38% of children with ALL present a white
blood cell count of more than 20 x 10˄9/L. In this case, the 10-year old child whose WBC is 50

Haematology and Blood Transfusion 4
x 10 ˄9/L is likely to have acute lymphoblastic leukaemia. Several confirmatory tests such as
bone marrow biopsy, cytogenic tests, molecular tests, peripheral smears, and flow cytometry can
be done to confirm this diagnosis.
The vital organ used for testing leukaemia is the bone marrow. Thus, marrow aspiration
and biopsy tests are essential tests in the diagnosis of ALL (Stephen et al. 2015). Both
procedures can be done at almost the same time. A syringe is used to suck the liquid from a
patient’s hip bone marrow when carrying out the bone marrow aspiration procedure. On the
other hand, the bone marrow biopsy procedure can be done after the aspiration procedure where
marrow is obtained for further diagnosis.
Cytochemistry can also be used to confirm the diagnosis for the 10-year old child. In this
test, cells are placed on slides that are then exposed to staining agents. Notably, the stains will
react with only specific leukaemia cells. For example, a dye may color the cells with acute
lymphoblastic leukaemia blue while leaving the unaffected cells intact. Under microscopy, the
stained cells can help hematologist-oncologists to define the type of leukaemia cells present in
the patient’s cell samples (Cooper & Brown 2015).
Cytogenetic tests will help in the diagnosis of the various sub-types of ALL. This test
involves the examination of whole chromosomes via karyotyping or hybridization of the cells in
situ. Normal chromosomes have 23 chromosome pairs, but in patients with ALL, their
chromosomes may have an abnormal number of chromosomes. The recognition of the numerical
change in chromosomes will help identify the three sub-types of ALL (Cooper & Brown 2015).
Equally important, it will be crucial in determining the child’s outlook and their response to
treatment. Cytogenetic testing helps identify chromosomal abnormalities; hence, the diagnosis
for leukaemia subtypes (L1, L2, and L3).