L21-22 - White Cell Disorders and Their Investigations Flashcards
Compare the changes in the haematopoeitic system under reactive or malignant change.
Reactive = Mainly quantitative changes** in normal cell types, Qualitative changes possible, e.g. atypical lymphocytosis
Malignant = Primary abnormality of haemopoietic system. Usually both quantitative and qualitative changes
List the 5 lab investigations of WBC disorders.
- Complete blood count
- Morphology, including: PBS, BM aspirate, trephine biopsy, cytochemistry
- Immunophenotype, including: Flow cytometry, immunohistochemistry
- Cytogenetics: Karyotyping, FISH
- Molecular genetics: PCR-based
Limitation of machine differential CBC?
Not good for blasts; good if only neutrophil, lymphocyte, monocyte, eosinophil, basophil
Always verify with manual count if in doubt
Function of Peripheral blood smear?
Confirm nature of cytopenia / increased white cell count
Detect abnormal cell types / abnormal morphology
Advantages and disadvantages of BM aspirate for white cell disorder?
Adv: Good cytological detail:
- Determine cellularity
- Detect dysplastic morphology
- Assess haemopoiesis of diff. lineages
Disadv:
- Architecture not preserved
Advantages and disadvantaged of Trephine biopsy for white cell disorder?
Adv:
- Preserves bone marrow architecture: assess marrow cellularity, pattern of abnormality, structure
- Allows immunophenotyping by immunohistochemistry
Disadv:
- Less sensitive than aspirate for cytological detail
- More invasive
Compare the technique for cytochemistry of myeloid lineage vs lymphoid?
Myeloid = Myeloperoxidase (MPO: in neutrophils) Sudan Black B (SBB)
Lymphoid = immunophenotyping to classify (no good cytochemistry)
Compare what is investigated in cytochemistry vs immunophenotyping?
Cytochemistry = Uses microscopy to detect dye / reaction product*** in the cells of interest
Immunophenotyping: Detects antigens* on cells of interest = determines cell lineage*
List the antigens used to differentiate myeloid vs lymphoid lineages in immunophenotyping? exam
Myeloid lineage:
Myeloperoxidase (MPO) (exam)
CD117, CD13, CD33
Lymphoid lineage:
B-ALL: CD19 (exam), CD79a, CD22
T-ALL: CD3 (exam)
Define whats investigated by flow cytometry?
investigate co-expression of antigens on a single cell
peripheral blood or marrow aspirate
What tissues are assessed in flow cytometry vs immunohistochemistry vs cytochemistry?
Cytochemistry = peripheral blood / bone marrow aspirate
Immunohistochemistry = trephine biopsy
Flow cytometry = peripheral blood / bone marrow aspirate
Immunohistochemistry is a good technique for investigating co-expression of Ag on single cell. T or F?
False
Flow cytometry used instead for finding co-expression of Ag
Karyotyping asseses cells in which phase of cell cycle?
study of chromosomes at metaphase stage*** of Mitosis when chromatin is highly condensed
Principle of FISH?
Single-stranded DNA probes attached with fluorophores/fluorochromes
> > form hybrid double-stranded complexes with their complementary genomic DNA sequences in cell
What is investigated by FISH?
Fluorescence in-situ hybridisation
Investigate:
Increase / decrease in copy number of target genes
Whether there is fusion of target genes
What is the most common cause of leucocytosis? exam
Quantitative WBC disorder = mostly reactive causes
List some causes of neutrophilia?
· Infections: Bacterial, esp. pyogenic
· Inflammation
· Malignancy
o Solid tumours
o Haematological: Myeloproliferative neoplasms, esp. CML, MF
· Drugs o Steroid (demargination of neutrophils), growth factors etc.
List some P/E or clinical presentation signs of neutrophilia caused by Infection? Investigation?
Fever Cough Sputum Diarrhea Dysuria
Microbioloical investigations (i.e. sputum culture, AFB smear, culture)
List some P/E or clinical presentation signs of neutrophilia caused by Inflammation? Investigation?
Symptoms/signs: Skin rash Photosensitivity Joint pain etc.
Inflammatory markers:
o Erythrocyte sedimentation rate (ESR)
o C-reactive protein (CRP)
Autoimmune markers
List some P/E or clinical presentation signs of neutrophilia caused by Malignancy? Investigation?
Cachexia / weight loss
Masses
Lymphadenopathy
Blood-stained sputum
- PBS +/- Marrow exam
- Cytogenics
- Molecular genetics
- Tumour markers
- Radiological scans
Types of malignancies that cause neutrophilia?
- Solid tumours: WBC reaction or paraneoplastic causing neutrophilia
- Haematological: Myeloproliferative neoplasms***: esp. CML and Myelofibrosis
What are the expected cytogenetic and molecular genetic results of CML?
Cytogenetics: t(9;22) Translocation = Philadelphia chromosome
Molecular genetics (e.g. PCR): BCR-ABL1 fusion transcript (defining mutation of CML)
Most common cause of Basophilia? 2 Less common causes?
myeloproliferative neoplasms** (especially chronic myeloid leukemia (CML))
Less common:
Autoimmune diseases, IBD Acute hypersensitivity
3 causes of Monocytosis?
Infections (especially tuberculosis, bacterial infections)
Autoimmune diseases
Chronic myelomonocytic leukaemia (CMML)
List some DDx of spenlomegaly?
- Portal hypertension
- Infection: esp. infective endocarditis, infectious mononucleosis, malaria, schistosomiasis
- Autoimmune diseases
- Storage diseases (in paediatrics)
- Haematological diseases causing sequestration (e.g. sickle cell anaemia)
What haematological diseases can cause splenomegaly?
Myeloproliferative neoplasm (can be massive in CML & MF),
lymphomas and leukaemias
Thalassaemia intermedia or major
Haemolytic anaemia