Laboratory Investigation of White Cell Disorders Flashcards Preview

Sem 4: TI2 > Laboratory Investigation of White Cell Disorders > Flashcards

Flashcards in Laboratory Investigation of White Cell Disorders Deck (12):
1

Describe the role of lymphocytes and the 3 main types. 

  • Adaptive immune response - differentiation between self and non-self, produce antibodies. 
  • Memory cells. 
  • 3 cell types: T cells, B cells, natural killer (NK) cells.
  • T cells - cell-mediated immunity - CD4+ T-helper cells, CD8+ cytotoxic T-cells. 
  • B-cells - humoral immunity - antibody production.
  • NK cells - innate immune system - attack virally infected cells and tumour cells. 

2

Name the derivatives of the myeloid and lymphoid progenitor cells. 

Myeloid progenitor: 

  • Neutrophils
  • Monocytes
  • Eosinophils 
  • Basophils 
  • Erythroid > red blood cell 
  • Megakaryocytes > platelets 

Lymphoid progenitor:

  • B cells
  • T cells
  • NK cells

3

Describe the normal range for WBC and neutrophil count and the disorders arising from aberrant numbers. 

  • WBC normal range = 4.0 - 11.0 x 109 / L
  • Neutrophil normal range = 2.0 - 7.5 x 109 / L 
  • Leucocytosis - increase in WBC
  • Leucopenia - decrease in WBC
  • Neutrophilia - increase in neutrophils
  • Neutropenia - decrease in neutrophils 

4

Name the physiological and pathological causes of neutrophilia. 

Normal physiological reaction: Post-operative, pregnancy

Other causes:

  • Bacterial infection
  • Inflammation - e.g. vasculitis 
  • Carcinoma 
  • Steroid treatment
  • Myeloproliferative disorders 
  • Treatment with myeloid growth factors

5

Describe the changes that may be associated with neutrophilia. 

  • Toxic granulation - seen in severe infection
  • Shift to the left - increased proportion of premature neutrophils and precursors (myeloid progenitors) in the blood. 
  • Shift to the right - increased proportion of hypersegmented neutrophils. 
  • Dohle bodies - blue inclusions on periphery of neutrophils - often seen with toxic granulation. 

6

What investigations should be undertaken if neutrophilia is found? 

  • FBC, differential WBC count
  • Blood film examination
  • Bacterial culture screen for infection
  • Bone marrow examination
  • Chromosome analysis for chronic myeloid leukaemia - Philadelphia chromosome (translocation between 9 and 22), molecular analysis for BCR-ABL oncogene

7

Name the causes of neutropenia. 

  • Viral infection
  • Drug-induced - e.g. sulphonamides 
  • Radiotherapy and chemotherapy 
  • Part of pancytopenia in bone marrow failure (aplastic anaemia) or infiltration e.g. leukaemia
  • Racial - "benign ethnic neutropenia"

8

Describe the possible causes and investigation of eosinophilia. 

  • Causes - allergic diseases, parasitic infections, drug sensitivity, myeloproliferative diseases e.g. chronic myeloid leukaemia, Hodgkin's lymphoma. 
  • Investigation - FBC, differential WBC count, blood film examination, stool examination for ova and parasites.

9

Describe the possible causes and investigation of monocytosis. 

  • Causes - tuberculosis, leukaemia, malaria. 
  • Investigation - FBC, differential WBC count, blood film examination for abnormal WBCs + malarial parasites, bone marrow examination for leukaemia, TB cultures.

10

Describe the possible causes and investigation of lymphocytosis. 

Causes:

  • Lymphocytosis of childhood (1-6 years) - normal
  • Bacterial or viral infection
  • Leukaemias and lymphomas

Investigation:

  • FBC and differential WBC count
  • Blood film examination - atypical mononuclear cells - glandular fever (caused by EBV)? 
  • Infectious mononucleosis (glandular fever) test

11

Outline the cause of infectious mononucleosis. 

  • Usually caused by Epstein-Barr Virus (EBV). 
  • Acute infection results in production of heterophile antibodies - antibodies which react against a different antigen to the one that stimulated the reaction. 
  • Presence of heterophile antibodies confirms diagnosis. 

12

How is lymphocytosis with mature lymphocytes investigated?

  • Chronic lymphocytic leukaemia or lymphoma?
  • Immunophenotyping. 
  • Do B-cells demonstrate clonality by light-chain restriction?
  • Do T-cells demonstrate clonality by T-cell receptor gene rearrangement studies?