Lab Investigation of White Cell Disorders

Question 1

What do the suffixes -philia and -penia mean?

Answer 1

• philia: high

- penia: low

Question 2

What are some physical characteristics of a normal neutrophil?

Answer 2

• has 3-5 lobes
• is granular
• is larger than a red cell

Question 3

What are some physical characterostcs of a normal lymphocyte?

Answer 3

• pretty much the same size a red cell, ever so slightly bigger
• hardly any cytoplasm seen
• very large, dense nucleus

Question 4

Describe lymphocytes.

Answer 4

Their major role is in Adaptive Immune Response.

With them, there is differentiation between self and non-self bodies.

e.g. Viral attack
Lymphocytes produce antibodies to destroy that virus

They’ll also make memory cells to allow a faster response to second exposure.

Question 5

What are the 3 major types of lymphocytes?

Answer 5

• T-cells
• B-cells
• natural Killer (NK) cells

Question 6

Descirbe the major function of each of the three types of lymphocytes.

Answer 6

T-cells are involved in cell-mediated immunity - CD4+ T-Helper cells and CD8+ Cytotoxic T-cells.

B-cells are involved in humoral immunity i.e. antibody production.

NK cells are part of the innate immune system, attacking virally infected cells and tumour cells.

Question 7

When is neutrophilia normal and when is it not?

Answer 7

NORMAL:

• post-operative
• pregnancy

OTHER CAUSES:

• bacterial infection
• inflammation (eg. vasculitis, MI)
• carcinoma
• steroid treatment
• myeloproliferative disorders
• treatment with myeloid growth factors

Question 8

How would you investigate neutrophilia?

Answer 8

• FBC and differential white cell count
• blood film examination
• bacterial culture screen for infection
• bone marrow examination + chromosome analysis for chronic myeloid leukaemia -
• Philadelphia chromosome: translocation between chromosomes 9 and 22
• molecular analysis for BCR-ABL oncogene

Question 9

List some causes of neutropenia.

Answer 9

• viral Infection
• drug Induced e.g. sulphonamides
• radiotherapy and chemotherapy
  part of a pancytopenia in bone marrow failure (aplastic anaemia) or infiltration e.g. leukaemia
• racial: ‘benign ethnic neutropenia’

Question 10

List some causes of eosinophilia.

Answer 10

• allergic diseases e.g. asthma, hayfever
• parasitic infections
• drug sensitivity
• myeloproliferative diseases e.g chronic myeloid leukaemia
• Hodgkin’s Lymphoma

Question 11

How do we investigate eosinophilia?

Answer 11

• FBC and differential white cell count
• blood film examination
• stool examination for ova and parasites

Question 12

List some causes of monocytosis.

Answer 12

• tuberculosis (TB)
• acute and chronic monocytic and myelomonocytic leukaemia
• malaria

Question 13

How would you investigate monocytosis?

Answer 13

• FBC and differential white cell count
• blood film examination:
  for abnormal white blood cells
  for malarial parasites
• bone marrow examination - leukaemia
• TB cultures

Question 14

When is lymphocytosis normal and when is it not?

Answer 14

NORMAL:
- lymphocytosis of childhood (1-6 years)

OTHER:

• bacterial infection
• viral infections (hepatitis, mumps, rubella, pertussis, glandular fever)
• leukaemias and lymphomas

Question 15

How would you investigate lymphocytosis?

Answer 15

• FBC and differential white cell count
• blood film examination

We’re looking for: atypical mononuclear cells.

We also do immunophenotyping to determind in lymphocytes are:

• B-Cells: demonstrate clonality by light chain restriction
• T-Cells: demonstrate clonality by T-cell receptor gene rearrangement studies

Question 16

What is infectious mononucleosis (glandular fever)?

Answer 16

Heterophile antibodies are antibodies which react against an antigen which is completely unrelated to the antigen which originally stimulated it.

e.g. human antibodies reacting against sheep or horse or bovine cells