2.2 High White Blood Counts due to Bone Marrow Diseases

Question 1

MUTATIONS
Mutations can be classified into type 1, type 2 and anti-apoptosis:

Type 1

• Affect control of cell proliferation → too many cells produced
• Causing build-up of too many ______________ cells (e.g. leukaemia) or ____________ cells (e.g. MPNs)

Type 2

• Impair/block _____________
• __________ dominate in the BM and spill into the circulation

Type 3

• Affect the apoptotic pathways
• Prevents usual cell death and prolongs survival

Answer 1

immature undifferentiated;

mature well differentiated;

cellular differentiation;

Immature cells;

Question 2

Tyrosine kinases belong to an important family of enzymes that phosphorylate proteins important in intracellular signalling:
• Growth factors attach to their receptors, activating intracellular tyrosine kinase domains which then transmit cell growth signals to the nucleus

The Janus kinase (JAK) is activated when a _________________ stimulates its receptor:
• JAK phosphorylates itself and a ________________
• STAT molecule then enters the nucleus and binds to DNA in gene promoter regions to turn on expression of the gene
• Several STAT proteins exist, which bind to different sequences of DNA to affect cell growth, differentiation and death

Answer 2

haematopoietic growth factor;

STAT (signal transducer and activation of transcription) molecule;

Question 3

Mutations leading to haematological malignancies are commonly point mutations or chromosomal translocations (creates novel fusion gene or disrupts proto-oncogene)

Point mutation ____________: Causes constitutive activation of JAK2 (critical in many MPNs) → 99% of _________________, 50% of essential thrombocythaemia, 50% of idiopathic myelofibrosis

Chromosomal translocation Philadelphia chromosome:
Reciprocal translocation between chromosomes 9 and 22 to form a shortened Philadelphia chromosome (22)
• _________________ on chromosome 9 is translocated beside the ________ on chromosome 22 → BCR-ABL fusion gene
• BCR-ABL gene product has enhanced tyrosine kinase activity
• Closely associated with chronic myeloid leukaemia (CML)

Answer 3

JAK2 V617F;

polycythaemia vera;

ABL gene (tyrosine kinase);

BCR gene

Question 4

These malignancies may exist in isolation or as overlap syndromes:

• Leukaemia : ___________________
• MPNs: Excess proliferation and differentiation
• MDSs: Ineffective proliferation and differentiation

Answer 4

Proliferation with abnormal differentiation

Question 5

LEUKAEMIA

The four main important types of leukaemias are listed below:

• Acute myeloid leukaemia (AML): Severe sudden _______________ at any age → death without treatment
• Acute lymphoid leukaemia (ALL): Occurs mainly in children → potentially curable (in >70% of patients) with chemotherapy
• Chronic lymphoid leukaemia (CLL): Associated with ____________ → may not require any treatment (mild)
• Chronic myeloid leukaemia (CML): Presents in middle-aged adults with ___________ → no problem initially but may transform to aggressive AML if left untreated

Answer 5

bone marrow failure;

chest infections in elderly;

enlarged spleen

Question 6

[Myeloproliferative Neoplasms] 
Myeloproliferative neoplasms (MPNs) are characterised by an increase in \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_- usually with more than one lineage increased:
• Patients with MPNs may feel well, but may also present with several findings including \_\_\_\_\_\_\_\_\_\_\_\_, high risk of thrombosis (PV, ET), enlarged spleen (MF, CML), risk of transformation into acute leukaemia 

• Polycythaemia vera (PV): Uncommon slow-growing haematological malignancy causing ____________________
• Essential thrombocythaemia (ET): Rare chronic condition with excess production of ___________ → may rarely transform into AML or MF
• Myelofibrosis (MF): Severe BM disorder disrupting the normal production of blood cells leading to ___________
• Chronic myeloid leukaemia (CML)

Answer 6

mature cells (red, white, or platelets);

hyperviscosity (PV, CML);

excess production of all blood lineages (mainly RBCs);

platelets;

scarring of the BM

Question 7

[Myelodysplastic syndromes] 
Myelodysplastic syndromes (MDS) are a group of disorders characterised by the \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ which often culminate in acute leukaemia:
• Premalignant changes which are resistant to treatment
• Tend to undergo a progressive downhill course (speed of deterioration linked to type of myelodysplasia) → low Hb, WBC, platelet count 

Classification

• Anaemia with/without increased blasts
• Anaemia with/without ring sideroblasts: Ring sideroblasts are erythroblasts with ___________________
• Chronic myelomonocytic leukaemia: May have raised WBC due to __________

Answer 7

disordered production of blood cells;

iron-loaded mitochondria (perinuclear ring of blue granules);

monocytosis

Question 8

The above conditions lead to changes in the WBC count, while lymphomas and myelomas are characterised by normal WBC counts

• Lymphoma: Increased WBC in _________ (but not in PB)
• Myeloma: Increased WBC (plasma cells) in the _____________ (but not in PB unless in plasma cell leukaemia)

Answer 8

lymph nodes or reticuloendothelial system;

bone marrow

Question 9

INVESTIGATIONS
There are 3 things to consider when investigating a raised WBC count:
1. History and physical examination
2. Automated differential (when looking at the rest of the blood count)
3. Examination of peripheral blood film

In the history taking, there are several important questions to ask the patient:
- Whether the patient feels ill
→ __________________: often feel ill
→ ________________: unlikely
- Duration: Acute leukaemia or glandular fever have short histories of days or weeks
- Symptoms of infection (e.g. cough, fever): Sign of underlying infection or immunocompromise from acute/chronic leukaemia
- Travel history: Increased reactive WBCs secondary to infections (exposed to microorganisms in other parts of the world)
- Bruising or bleeding: Suggests low platelet count (indicating more global BM problem like ____________)

During the physical examination of the patient, it is important to take note of:
• Whether the patient appears unwell
• Bruising or bleeding
• Signs of infection
• Enlarged lymph nodes (lymphadenopathy)
• Enlarged spleen (splenomegaly)

Answer 9

Acute leukaemias, glandular fever;

MPN, MDS, chronic leukaemias;

acute leukaemia

Question 10

When looking at the patient’s blood count, it is important to note the extent of increase in WBC count and also how the rest of the blood count appears:
• The lineage and degree of maturity of the white cells, as well as whether they are polyclonal or monoclonal (distinguishes reactive from malignant) must be noted
• ______ WBC, ______ Hb and platelets: BM is full of abnormal cells → leukaemia
• ___ WBC, ____ Hb and platelets: all lineages are increased → MPN

The following table shows the different parameters measured in a full blood count and their associated normal levels:

• Hb: ________ g/L
• Platelets: 150 – 400 x 109 /L
• White cell count: _____ x 109 /L
• Neutrophils: _______ x 109 /L
• Lymphocytes: _______ x 109 /L
• Monocytes: 0.2 – 0.8 x 109 /L
• Eosinophils: 0.04 – 0.44 x 109 /L
• Basophils: 0.01 – 0.10 x 109 /L

Answer 10

High, low;

High. high;

120 – 160;

4 – 11;

2. 5 – 7.5;
3. 5 – 3.5

Question 11

Neutrophilia may be reactive (in response to infections) or malignant:

Reactive neutrophilia

• Neutrophil count > 7.5 x 109/L
• Blood film shows ________________

Malignant neutrophilia

• Neutrophil count > 7.5 x 109/L
• Blood film shows ____________________-
• Characteristic of chronic myeloid leukaemia (early white cells, basophils, eosinophils in PB)

Answer 11

mature neutrophils (with vacuoles and toxic granulation) and RBCs;

mature neutrophils, precursor cells (myelocytes), RBCs, basophils, eosinophils

Question 12

[Lymphocytosis]
Mature lymphocytosis may be reactive (due to infections e.g. EBV) or a primary disorder (e.g. CLL), while immature lymphocytosis is likely a primary disorder (e.g. leukaemia, lymphoma):
• Classical appearance of atypical lymphocyte: ______________________ (extensive compared to normal lymphocytes)

Mature lymphocytosis
Blood film shows mature lymphocytes (with _______________)
*Seen in __________________

Immature lymphocytosis
Blood film shows immature lymphocytes, (seen from ________)
*Characteristic of acute lymphoblastic leukaemia

Investigating the clonality of lymphocytes may be done via immunophenotyping (with fluorescence flow cytometry) or Southern blot analysis:
• Light chain restriction: B cell (CD20+) populations should generally have a mixture of _______________ → monoclonality (only 1 predominant type) suggests a clone (B cell malignancy)
• Southern blot analysis: gene rearrangement
studies of immunoglobulin genes and TCR genes (which undergo recombination in antigen-stimulated cells) → clones carry identical configurations of the genes

Answer 12

large nucleus with cytoplasm skirting around the RBCs;

large nucleus and less cytoplasm;

chronic lymphoid leukaemia or autoimmune/inflammatory diseases;

pale nucleus;

κ and λ antibody light chains

Question 13

Eosinophilia may be reactive or malignant:

Reactive eosinophilia:

• Parasitic infections
• Allergic diseases (e.g. asthma, RA, polyarteritis, pulmonary eosinophilia)
• Neoplasms (especially Hodgkin’s disease, T cell non-Hodgkin’s lymphoma)
• Hypereosinophilic syndrome

Malignant eosinophilia
- Chronic eosinophilic leukaemia (rare) → associated with fusion gene involving the ___________

Answer 13

PDGF gene

Question 14

Monocytosis may be reactive or malignant:

Reactive monocytosis

• Chronic infections (e.g. _______________)
• Chronic illness (e.g. sarcoidosis)

Malignant monocytosis
- Chronic myelomonocytic leukaemia (CMML) → type of mixed _________

Answer 14

TB, brucella, typhoid, CMV, VZV;

MPN/MDS