White Blood Cells/Spleen/Immune System

Question 1

Overview of Immune System summary

Answer 1

Tissues
- bone marrow
- thymus
- spleen
- lymph nodes
Cells
- leukocytes
- macrophages
- antigen presenting cells
Proteins
- immunoglobulins
- complement proteins

Question 2

What are complement proteins job

Answer 2

protect intravascular space from bacterial infection
clear tissue debris
wound healing

Question 3

What is humoral immunity

Answer 3

B cells -> plasma cells -> antibodies

Question 4

What is cellular immunity

Answer 4

T cells -> cytotoxic (eat other cells)
T cells -> activate macrophages
T cells -> direct humoral immune response

Question 5

Spleen summary (function, size, indications for splenectomy)

Answer 5

Function:
hematopoiesis (Primarily - fetal life)
filtering (remove old/deformed RBC)
immune defense (encapsulated bacteria)

Size:Normal 150 gm, 13 (up to 15) cm long

splenectomy indications:
Immune cytopeniashematologic malignancy
RBC membrane/enzyme disorders
Thalassemia
TTP
trauma

splenectomy consequences:
Leukocytosis
Thrombocytosis
Howell-jolly bodies
infection risk

Question 6

Neutrophils summary

Answer 6

MC (45-75%) WBC
Neutrphil count < 100/uL great risk infection

Function: find, ingest, kill invading microorganisms

What Increase Neutrophils:
Bacterial infection
physiological stress
corticosteroids

What Decrease neutrophils:
viral infection
drugs/toxins
Brucella infections

Question 7

Lymphocytes summary

Answer 7

20-45% WBC

Circulate in blood and populate lymphoid tissue

Function: generation and regulation of immune responses

Types:
B cells
T cells
NK cells

what increase neutrophils:
viral infections

Question 8

B lymphocytes summary

Answer 8

mature in bone marrow

5-25% peripheral lymphocytes

differentiate into plasma cells which make antibodies

Question 9

T lymphocytes summary

Answer 9

mature in thymus

60-85% peripheral lymphocytes

Types:
Helper T
- regulate immune system
- cause B cells to become plasma cells

Cytotoxic/suppressor T

• recognize and kill virus-infected cells
• recognize and kill foreign cells
• down regulate antibody production from plasma cells

Question 10

Natural Killer Cells summary

Answer 10

5-20% peripheral lymphocytes

prevent growth and spread of tumors

Question 11

Monocytes summary

Answer 11

Become macrophages in tissue

Function:
phagocytize microorganisms
antigen presenting cells
induce fever and inflammation

Increase due to:
chronic infections (TB)
lymphomas
granulomatous disease (sarcoid)

Question 12

Eosinophils summary

Answer 12

Function: release granules that kill parasitic pathogens

Eosinophil increase:
chronic inflammatory skin disorders
parasitic dx
hypersensitive states (allergy)
malignancies

Can damage organs when release granules

Question 13

Basophils summary

Answer 13

Function: IgE and antigen bind causing basophil to release substances with vasoactive and inflammatory properties

Basophils increase:
allergic disorders
myeloproliferative diseases (CML, polycythemia vera)

Question 14

What dx cause leukopenia

Answer 14

Decreased production

• B12/folate deficiency
• marrow aplasia/dysplasia
• marrow replacement
• marrow damage
• autoimmune

Increased destruction/consumption

• hypersplenism
• autoimmune
• overwhelming infection/sepsis

Question 15

What dx cause leukocytosis

Answer 15

Reactive:

• Bacterial infection
• Viral infection
• parasitic infection
• inflammation
• physiologic stress
• drug induced
• asplenia

Malignant:

• hematologic
• non hematologic

Question 16

What are important leukocyte counts

Answer 16

< 2,000 or > 50,000 hematologist

4,000 - 10,000 normal