6. Abnormal white cell count Flashcards
What are the different stages of myeloid maturation into a neutrophil?
- Myeloblast - large cell with high nucleus:cytoplasmic ratio, not many granules
- Promyelocyte - large, heavy granulation
- Myelocyte - eccentric nucleus, smaller cytoplasm
- Metamyelocyte
- Neutrophil
When do you see cells that are in the differentiating phase (into neutrophils) in peripheral blood?
Septic patients
• Leukoerythroblastic picture
- myeloid precursors with nucleated red cells
• Bone marrow is trying to compensate for peripheral destruction
Chemotherapy patients
• Immature myeloid cells
• White cell count falls
• Given G-CSF growth factor
Chronic myeloid leukaemia
• Presence of cells at all stages of differentiation
What stimulates the process of myeloid maturation?
Cytokines and growth factors
What mediates the production of lymphoid cells?
IL2 along with other cytokines
Which growth factors mediate the production of myeloid cells?
G-CSF and M-CSF
Where should immature white blood cells be found?
Only in the bone marrow
What is reactive and malignant white cells production?
- Reactive - increased production during infection and inflammation
- Malignant - increased count in leukaemia and can be myeloproliferative
How do the following affect the WBC count:
• Impaired bone marrow function
• Bone marrow failure
• B12 or folate deficiency
- Impaired bone marrow function - reduced WBC
- Bone marrow failure - reduced WBC in aplastic anaemia, chemotherapy, metastatic/haematological cancer
- B12 or folate deficiency - reduced WBC
What is the most common cause of eosinophilia?
Reactive and secondary to drugs
What are the reactive causes of eosinophilia (where haemopoiesis is normal)?
- Inflammation
- Infection (parasites)
- Increased cytokine production (due to a distant tumour, haematopoietic or non-haematopoietic)
- Neoplasms
- Hypereosinophilic syndrome
What are the primary (malignant) causes of eosinophilia (where haemopoiesis is abnormal)?
• Cancers of haematopoietic cells
• Leukaemia
• Myeloproliferative disorders
• Malignant Chronic Eosinophilic Leukaemia - mutation in the PDGFR gene
- IL5 stimulates production of eosinophils
How can you investigated a white cell count?
1) History and examination (enlarged spleen, lymph nodes)
2) Haemoglobin and platelet count
3) Automated differential
4) Examine blood film
- which blood cells affected
- which type if only WBC
- mature or immature involved
Which WBCs are increased in chronic lymphocytic leukaemia?
B lymphocytes - mature
Are the WBCs that are increased in acute lymphoblastic leukaemia mature or immature?
Immature
What affect does smoking have on WBCs?
- Elevated lymphocyte count
- Persistent lymphocytosis
- Persistant neutrophilia
- Can persist for many years after quitting smoking
What is the life span of neutrophils?
2-3 days in tissues, hours in the peripheral blood
How long does it take for neutrophilia to develop?
- Minutes - due to demarginaiton
- Hours - due to inflammation or infection
- Days - increased production
What are the causes of neutrophilia?
- Infection
- Tissue inflammation
- Physical stress, corticosteroids
- Underlying neoplasia
- Malignant neutrophilia
What causes monocytosis?
- TB, brucella, typhoid
- CMV, varicella zoster
- Sarcoidosis
- Chronic myelomonocytic leukaemia
What is basophilia a sign of?
- Rare
- Underlying haematological cancer
- Inflammation
What is lymphocytosis a sign of (including involvement of mature/immature cells)?
- Very common - reactive most of the time
- After the age of 70, can be a sign of underlying chronic lymphocytic leukaemia
- Mature cells - reactive response to infection
- Immature cells - reflective of primary disorder (leukaemia/lymphoma)
What is primary or secondary lymphocytosis (involving mature cells)?
- Primary - monoclonal (all the same) lymphoid proliferation
* Secondary - polyclonal response to infection, chronic inflammation or underlying malignancy
What are the reactive causes of lymphocytosis?
- Infection e.g. EBV
- Autoimmune disroders
- Neoplasia
- Sarcoidosis
What happens in glandular fever?
- EBV infection of B-lymphocytes via CD21 receptor
- Infected cell proliferates and expresses EBV associated antigens
- Cytotoxic T-lymphocyte response
- Acute infection is resolved resulting in lifelong sub-clinical infection
What can you used to analyse the configuration of the Ig, or TCR gene in primary monoclonal proliferation?
- Souther blot analysis
* Identical configuration
