Abnormal white cell count

Question 1

What is meant by pancytopenia

Answer 1

All blood cell lineages reduced

Question 2

What is meant by haemopoiesis

Answer 2

Haemopoiesis: production of blood cells in Marrow

Creation of mature blood cells

Question 3

Describe normal haemopoiesis

Answer 3

Normal haemopoiesis (polyclonal healthy/ reactive)
Normal marrow
Reactive marrow - very active bone marrow- in response to infection or inflammation for example.

Question 4

Describe malignant haemopoiesis

Answer 4

Malignant haemopoiesis (abnormal/clonal)
Leukaemia (lymphoid,myeloid), myelodysplasia, myeloproliferative 

Malignant- cancer cells divide from mother cells- same features as mother cells- clonality- fundamental feature of cancer- helps distinguish process from a benign condition

Question 5

Outline the cell lines that the haemopoietic stem cells can differentiate into

Answer 5

HSCs -- Pre T- T cell
HSC- Pre- B- B cell
HSC- Meg-CFC- Megakaryocyte/platelet
HSC- GM-CFC- Granulocytes and Monocytes
HSC- BFU-E- RBCs

§ HSCs can differentiate into many cell lines.
o BFU-E = Blast Forming Unit Erythrocyte.

Question 6

What are the granulocytes

Answer 6

Granulocytes (neutrophils, basophils and eosinophils)

Question 7

Describe the key properties of haemopoietic stem cells

Answer 7

Capacity for self-renewal

Multi-potent

Question 8

Which cells come under the myeloid cells

Answer 8

Erythrocytes 
Neutrophils 
Basophils 
Eosinophils 
Monocytes 
Macrophages 
Megakaryocytes 
Dendritic Cells

Question 9

What is the lymphoid lineage

Answer 9

Lymphoid cells are lymphocytes = T cells, B cells and NK cells

Question 10

What is important to remember about the differentiation and maturation of blood cell lineages

Answer 10

Different stages of maturation- normally exclusively seen in the bone marrow
Normal- should only see mature cells in the peripheral blood

Question 11

Describe two circumstances in which we may see immature cells in the peripheral blood

Answer 11

GCSF – growth hormone (daily injection in cancer patients to recover neutrophils after chemotherapy)
Following single injection- will see lots of different myeloid precursors

Sepsis- bone marrow tries to compensate for stressful situation- releases lots of myeloid precursors- typically immature white cells and nucleated red cells- presence together- leucoerythroblastic picture- important to recognise- indicates patient is septic or that the bone marrow is infiltrated by a tumour

Question 12

Outline the normal steps of differentiation to a mature neutrophil

Answer 12

myeloblast > promyelocyte > myelocyte > metamyelocyte (> neutrophil)

First 4 steps occur in the bone marrow
Hence only mature neutrophils should be seen in the peripheral blood.

Question 13

Describe how the appearance of white cells changes as they develop.

Answer 13

They become smaller and their cytoplasm becomes clearer.

Will also develop a multi-lobed nucleus.

Question 14

Describe the chemicals that influence differentiation and proliferation

Answer 14

Cytokines influence differentiation and proliferation

o RBCs – EPO.
o Lymphoid cells – IL-2.
o Myeloid cells – G-CSF, M-CSF.

Question 15

What can affect these regulating cytokine signals

Answer 15

DNA directed differentiation and proliferation
§ DNA damage in cancer can affect these regulating signals and lead to the cancer proliferation.
o Leukaemia – malignant process in primary lymphoid organs.
o Lymphoma/Leukaemia – lymphatic cell tumours in tissue/blood.
o Myeloma – disease of bone marrow.

Question 16

What can be given to patients with renal impairment to help manage the anaemia

Answer 16

Renal impairment- defective EPO- can treat with recombinant EPO- which improves the anaemia

Question 17

Describe the two main groups of white cells and their overall function

Answer 17

White cells consist of two main groups:
Phagocytes; including monocytes and granulocytes, the subtypes of the latter including neutrophils basophils and eosinophils
Immunocytes; which consist of T and B lymphocytes. These cell types will react in response to different stimuli.
Both cell groups are present throughout body tissues and play a central role in the response to infection mediated via phagocytosis and soluble proteins of the immunoglobulin and complement system.

Question 18

What do cells of the lymphoid lineage differentiate from

Answer 18

Lymphoblasts

Question 19

What do the phagocytic cells differentiate from

Answer 19

Myeloid lineages

Myeloblasts
Promyelocytes
Myelocytes
Metamyelocytes

Question 20

What is the key difference between the lymphoid tissue and peripheral blood

Answer 20

Lymphoid tissue vs peripheral blood: only mature cells in blood, mix of immature and mature cells in tissue

Question 21

Broadly speaking, what two things can result in a leucocytosis

Answer 21

Increased white blood cell production

Increased white blood cell survival

Question 22

Describe how an increased white blood cell production can lead to a leucocytosis

Answer 22

Reactive (essentially, a normal physiological response)
Infection (sepsis)
Inflammation

Malignant
Leukaemia
myeloproliferative
Clone of abnormal cells- acquired mutation that allows them to proliferate uncontrollably – malignant

Question 23

What is the difference in the type of white blood cell seen in the peripheral blood of someone with an infection/inflammation (reactive) and someone with a malignancy (primary)?

Answer 23

Reactive – only mature white blood cells (to respond to the infection or inflammation)
Primary – mature AND immature white blood cells present

Question 24

Describe how increased cell survival can cause a leucocytosis

Answer 24

Failure of apoptosis (eg acquired cancer causing mutations in some lymphomas

Mutations in onco-suppressor genes- allows the cells to proliferate uncontrollably

Question 25

Broadly speaking, what two things can result in a leucoocytopenia

Answer 25

Decreased white blood cell production | Decreased White blood cell survival

Question 26

Describe how a decreased white blood cell production can lead to a leucocytopenia

Answer 26

``` Impaired BM function B12 or Folate deficiency BM failure Aplastic anaemia Post chemotherapy Metastatic cancer Haematological cancer ```

Question 27

Where is B12 of folate deficiency particualry common

Answer 27

Vegans | Can generally result in a pancytopenia

Question 28

Describe how a decreased cell survival can lead to a leukocytopenia

Answer 28

Immune breakdown Auto-antibodies against immune cells- many connective tissue disorders- but also in Autoimmune diseases.

Question 29

Describe a reactive eosinophilia

Answer 29

Inflammation Infection (usually parasitic- but any infection can increase eosinophil count) Increased cytokine production (pan-neoplastic effect of some tumours): -Distant tumour -Haemopoietic or non haemopoietic Eosinophils will retain normal morphology Usually associated with other white cell abnormalities- monocytosis and neutrophilia Rarely associated with symptoms

Question 30

Describe pan-neoplasms that can cause a reactive esopinophilia

Answer 30

Important to investigate Isolated tumours and hemopoietic cancers- Hodgking's lymphoma Release cytokines which trigger eosinophil production and proliferation.

Question 31

Describe primary (malignant) eosinophilia

Answer 31

``` AbnormalHaemopoiesis (autonomous cell growth) Cancers of haemopoietic cells Leukaemia: -Myeloid or lymphoid -Chronic or acute ``` Myeloproliferative disorders All myeloproliferative disorders- characterised by eosinophilia

Question 32

Where does the mutation occur in CML and describe the consequences of this mutation

Answer 32

Mutation at early stage of haematopoiesis- instead of apoptosis- increased proliferation of cells in granulocytic lineage and platelets and monocytes Very high white cell count Blood film- will show every stage of white cell maturation

Question 33

Summarise the first stages in investigating a leucocytosis

Answer 33

History and examination Haemoglobin and platelet count Automated differential (% and absolute number of each WC type) Examine blood film

Question 34

Describe why examination and history are so important

Answer 34

History- want to see if patient is symptomatic or not- leucocytosis can sometimes be a incidenta finding- patient asymptomatic- smoking- mild leuckocytosis in general population- common to see reactive lymphocytosis or neutrophilia Ask for recent travel history- eosinophilia- knowing patient been in African area with G.I symptoms- indicated parasitic infection On examination- focus on lymphadenothy and hepatosplenomegaly- underying lymho- or myeloprolierative disorder

Question 35

Describe why it is important to look at Hb and platelet counts

Answer 35

Look at what happens to Hb and platelets Isolated neutrophilia less concerning than combination with low Hb and raised white cell count Mild neutrophilia- which is long-lasting and not associated with symptoms- likely to be reactive Rarely with a patient with a low Hb, thrombocytopenia and raised WBC count- not something to be worried about- usually typical presentation of leukaemia

Question 36

Describe the importance of the automated differential

Answer 36

If you get no differential- machine cannot recognise what the cells are- GCSF injection (myeloid precursors which the machine cannot characterise) or presence of malignant condition When an elevated WBC is identified it is necessary to first look at the automated differential. Is the leucocytosis due to an elevation of a particular cell type i.e. an increase in one cell type only e.g. a lymphocytosis, a neutrophilia or an eosinophilia, or alternatively an increase in all cell types.

Question 37

Summarise the other key stages in investigating a leucocytosis

Answer 37

Abnormality White cells only, or all 3 lineages (red cells/platelets/white cells) ? White cells 1 cell type only, or all lineages? (e.g. neuts/eos/monocytes/lymphocytes) Mature cells only or mature and immature cells?

Question 38

Describe the importance of checking whether the abnormality is white blood cells only or all blood cell lineages

Answer 38

Can tell you what the disease is caused by Raised WBC, raised HB and platelet count- myeloproliferative disorder Malignant- only one type of white cell lineage increased – cancer is a clonal process- mother cell generated lots of daughter cells which are identical to the mother cell Thus the abnormality of one particular cells Chronic Lymphocytic Leukaemia - increased number of lymphocytes- but rarely any increase in myeloid cell lines

Question 39

Describe the importance of checking whether the abnormality is in one white cell lineage only or others (myeloid/lymphoid)

Answer 39

Reactive- all types involved- one exception- CML- patients can have increase in all white cells- lots of white cells- of all different myeloid precursors- eosinophils, basophils (otherwise rarely seen in blood), to be sure of CML > AML –look for presence of eosinophilia. Can tell you more about cause (reactive or malignant)

Question 40

Describe the usefulness in checking whether the cells are mature cells only, or a mixture of mature and immature

Answer 40

Mature or immature- doens’t do much in distinguishing reactive from malignant- in CLL- all mature cells but malignant but in CML- both mature and immature cells.

Question 41

Describe the potential causes of a leucocytosis where only mature cells are present

Answer 41

Lymphocytes Reactive(viral) or primary (chronic lymphocytic leukaemia All lineages or only one neuts, eos, baso-- reactive/infection

Question 42

Describe the potential causes of a leucocytosis where only immature cells are present

Answer 42

Blasts + low Hb low platelets ? Acute leukaemia

Question 43

Describe the potential causes of a leucocytosis where a mixture of mature and immature cells are present

Answer 43

``` Neutrophils+ myelocytes+ basophils ?Chronic myeloid leukaemia ```

Question 44

What are the normal ranges of the different parameters

Answer 44

``` a. Hb 120-160 g/L b. Platelets 150-400 x 109/L c. WCC 4-11 x 109/L d. Neutrophils 2.5-7.5 x 109/L e. Lymphocytes 1.5-3.5 x 109/L f. Monocytes 0.2-0.8 x 109/L g. Eosinophils 0.04-0.44 x 109/L h. Basophils 0.01-0.1 x 109/L ```

Question 45

What can an abnormal WCC be due to

Answer 45

§ Abnormal WCC can be caused by: o Phagocytes – neutrophils, eosinophils and monocytes. o Immune cells – lymphocytes (infection or CML).

Question 46

Describe the key features of neutrophils

Answer 46

Present in BM, blood and tissues Life span 2-3 days in tissues (hours in PB) 50% circulating neutrophils are marginated (not counted in FBC)

Question 47

What is the difference between the circulating pool and marginated pool of neutrophils

Answer 47

Some neutrophils represent circulating pool- but others are margianted (adhere to endothelial cells and migrate into different tissues) Balance between circulating and marginated pool- can change in minutes- stress- need more neutrophils- marginated pool can be switched into circulating- so neutrophilia can be developed in minutes

Question 48

Outline the time frames in which neutrophilia can develop

Answer 48

§ Neutrophilia can develop in: o Minutes – demargination. o Hours – early release from BM – i.e. sepsis. o Days – increased production – i.e. x3 in infection.

Question 49

Describe the features of neutrophils in the peripheral blood when caused by infection

Answer 49

Neutrophilia >7.5x109/l toxic granulation vacuoles Infection- abnormal neutrophils- white spots in cytoplasm (vacuoles)- abnormal distribution of granules- Neutrophils in leukaemia do not have granules and do not look toxic.

Question 50

Describe the features of neutrophils in the peripheral blood when caused by leukaemia

Answer 50

Chronic leukaemia Chronic myeloid leukaemia Neutrophilia and Precursor cells (myelocytes CML- lose different stages of myeloid differentiation Band cells- neutrophils with non-segmented nuclei.

Question 51

What else would be present in the blood film of someone with leukaemia that would not be present in someone with an infection?

Answer 51

Myelocytes and metamyelocytes – these precursors would not be found in the peripheral blood of someone responding to infection

Question 52

What are the different causes of neutrophilia

Answer 52

Infection Tissue inflammation (e.g.colitis, pancreatitis) Physical stress, adrenaline, corticosteroids underlying neoplasia Malignant neutrophilia myeloproliferative disorders CML

Question 53

Which infections may result in a neutrophilia

Answer 53

Localised and systemic infections | acute bacterial, fungal, certain viral infections

Question 54

Which infections will not produce a neutrophilia

Answer 54

Some infections characteristically do not produce a neutrophilia e.g. brucella, typhoid, many viral infections.

Question 55

Describe the causes of a reactive eosinophilia

Answer 55

1 Reactive Parasitic infestation Allergic diseases e.g. asthma, rheumatoid, polyarteritis,pulmonary eosinophilia. Neoplasms, esp. Hodgkin’s, T-cell NHL- may make IL-5 Hypereosinophilic syndrome- heart damage- >1.5 – need to treat patients to prevent organ damage- regardless of underlying cause Drugs also an important cause  Hodgkin’s disease will show up on x-ray with increased mediastinal mass and there will be increased IL-5 secretion (stimulates reactive).  You can also get a mutation in GM-CFC. Malignancy- leucoerythroblastic picture- abnormal granules

Question 56

Describe a cause of a malignant eosinophilia

Answer 56

Malignant Chronic Eosinophilic Leukaemia (PDGFR fusion gene) mutation in alpha or beta gene very rare

Question 57

Describe monocytosis

Answer 57

``` Rare but seen in certain chronic infections and primary haematological disorders TB, brucella, typhoid Viral; CMV, varicella zoster Sarcoidosis Chronic myelomonocytic leukaemia (MDS) ```

Question 58

Summarise the different causes of neutropholia

Answer 58

Bacterial - infection Auto-immune Tissue necrosis --- inflammation All types of neoplasia (cells not part of malignant population)

Question 59

Summarise the different causes of an eosinophilia

Answer 59

parasitic- infection Allergic (asthma, atopy, drug reactions)- inflammation Hodgkin’s NHL-- neoplasia (cells not part of malignant population)

Question 60

What is an infectious cause of a basophilia

Answer 60

Pox virus

Question 61

What is an infectious cause of mono

Answer 61

Chronic (TB, | Brucella)

Question 62

Summarise the different causes of lymphocytosis

Answer 62

Mature or immature cells If mature is it : reactive to infection primary disorder (CLL) ``` If immature it is: primary disorder (leukaemia/lymphoma) ```

Question 63

Compare different blood films in lymphocytosis

Answer 63

 LEFT picture: o Cells are like each other – oligoclonal expansion. o Could be CLL (Chronic Lymphocytic Leukaemia) or autoimmune conditions.  RIGHT picture: o Immature lymphoblasts are much larger and you can see a nucleolus which shows immaturity. o This is acute lymphoblastic leukaemia. nuclei will be pinker

Question 64

When we see mature cells in a lymphocytosis how can we easily distinguish between reactive and primary causes

Answer 64

Is it primary or reactive ? Secondary (reactive); polyclonal response to infection, chronic inflammation, or underlying malignancy. Primary; monoclonal lymphoid proliferation e.g. CLL

Question 65

What will be seen in mononucleosis syndrome

Answer 65

“atypical lymphocyte” Mononucleosis syndrome Night time sweating, fatigue Leukaemia- other lineages affectesd nucleosis- not much change in other lineages

Question 66

Describe the key features of glandular fever

Answer 66

 Shows a reactive-looking lymphocyte that looks like an immature lymphocyte seen in acute lymphoblastic leukaemia BUT these lymphocytes tend to have RBCs clump them and they are jagged and are not self-clumped.  High WCC with reactive-looking lymphocytes shows glandular fever.

Question 67

Describe the pathogenesis of glandular fever

Answer 67

EBV infection of B-lymphocytes via CD21 receptor Infected B-cell proliferates and expresses EBV associated antigens Cytotoxic T-lymphocyte response acute infection resolved resulting in lifelong sub-clinical infection. Cytokines from t-cells result in symtpoms

Question 68

Describe lymphocytosis in elderly patients

Answer 68

``` Elderly patients with lymphocytosis mature lymphocytes (may be smear cells) differential: reactive to underlying auto immune disorder or chronic lymphocytic leukaemia ``` How can you distinguish? Morphology Immunophenotype Gene re-arragement

Question 69

Describe how we can evaluate lymphocytosis using (B cell) light chain restriction

Answer 69

 Polyclonal expansion – involve more than one mother cell and so the light chains express both kappa and lambda. o This is indicative of a response to infection.  Monoclonal expansion – all antibodies are from ONE mother cell and this is indicative of a cancer

Question 70

Describe how we can evaluate lymphocytosis using gene rearrangement

Answer 70

Imuunoglobulin genes (Ig) and T cell receptor (TCR) genes undergo recombination in antigen stimulated B cells or T cells. With primary monoclonal proliferation all daughter cells carry identical configuration of Ig, or TCR gene. This can be detected by Southern Blot analysis

Question 71

What should we do when looking at an abnormal white cell count

Answer 71

Look at all aspects of FBC Look at automated differential Look at blood film

Question 72

Likely causes of eosinophila in patient with recent travel history

Answer 72

``` Parasitic infestation (schistosomiasis) Underlying lymphoma (HL or T NHL) allergic autoimmune disorder (asthma/urticaria) ```

Question 73

Describe case 2

Answer 73

 Cells are mature – nucleoli cannot be seen.  Cells are very like each other – monoclonal expansion. o Could be reactive – viral or TB. o Primary/monoclonal – CLL.  Further tests show there is light chain restriction (kappa restriction) so this is most likely CLL. Lymphoma- need lymph node biopsy- BM and blood normal Peripheral blood immunophenotype for light chain and ig, TCR type

Question 74

Describe case 3

Answer 74

 Cells are immature as they are irregular and have nucleoli.  Most likely acute lymphoblastic leukaemia.

Question 75

Describe case 4

Answer 75

 You can see neutrophils and neutrophil precursors.  Toxic granules cannot also be seen which should be seen in infection.  Basophils and myelocytes can also be seen.  There has been an expansion of the myeloid cells so this is CML.

Question 76

What else can cause an eosinophilia

Answer 76

Pulmonary eosinophilia. | Hodgkin’s disease, a cancer of the lymphatic system which may produce a reactive eosinophilia.

Question 77

Describe the response to a pyogenic bacterial infection

Answer 77

Increase in cell numbers: Infection by pyogenic bacteria will result in tissue damage and the production and release of a range of inflammatory cytokines. Amongst these may be factors such as granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) that will stimulate granulocyte and monocyte production by the bone marrow. More importantly in the acute response there will be the early release from the BM of less mature cells. This will result in an increase in the circulating granulocyte count and a left shifted appearance in the peripheral blood. Chemotaxis: The phagocytes will circulate in the peripheral blood, at the site of infection they will move out of the circulation and into the tissues moving to the site of inflammation in response to chemotactic factors. Phagocytosis: The neutrophils and monocytes will encounter foreign material that has been opsonised by immunoglobulin or complement. Using their Fc and C3b receptors they are able to recognise and phagocytose the foreign material. Killing and digestion: Ingested material will be killed within the phagocytic vacuoles by both oxidative and non-oxidative mechanisms.

Question 78

Describe the context of a lymphocytosis

Answer 78

When a lymphocytosis is identified in a FBC the blood film must be examined for the presence of: A typical / reactive lymphocytesseenin mononucleosis syndromes. Immediate response to acute stress (e.g. heart attack or other severe pain). Small lymphocytes and smudge cells seen in chronic lymphocytic leukaemia. Primitive blasts seen in acute lymphoblastic leukaemia.

Question 79

Describe reactive lymphocytosis

Answer 79

Infection EBV, CMV, Toxoplasma infectious hepatitis, rubella, herpes infections Autoimmune disorders neoplasia sarcoidosis

Question 80

What are the causes of a reactive lymphocytosis

Answer 80

Infection EBV, CMV, Toxoplasma infectious hepatitis, rubella, herpes infections Autoimmune disorders neoplasia sarcoidosis