Immunodeficiency

Question 1

What type of block is associated with low T and B cells?

Answer 1

Block type 1- Severe combined immunodeficiency Disease (SCID)

Question 2

What type of block is associated with high IgM and low IgG and IgA

Answer 2

Block type 3- X-linked HyperIgM syndrome

Question 3

What type of block is associated with absent T cells and normal B cells?

Answer 3

Block type 5- DiGeorge Syndrome

Question 4

What type of block is associated with normal numbers of pre-B cells and B cells but the B cells have difficulty producing antibodies?

Answer 4

Block type 4- Common Variable Immundeficiency (CVID)

Question 5

What type of block is associated with normal T cells but low to absent B cells?

Answer 5

Block type 2- X-linked Bruton’s Agammaglobinemia

Question 6

What is the problem in block type 3?

Answer 6

Defect in CD40 ligand or in CD40 on B cells. This surface marker induces the switch.

B cell is made but no switch is made past IgM.

Thus too much IgM.

Question 7

In which block type is there a defect in the stroma?

Answer 7

Block type 5- DiGeorge. Stroma develops abnormally and does not support lymphoid development in the thymus

Question 8

What kind of genetic pattern is SCID?

Answer 8

X-linked recessive.

Question 9

What kind of block involves a defect in the gene for the gamma chain that forms part of the receptors for IL2 and other cytokines necessary for lymphoid development?

Answer 9

Block 1 (SCID-X1)

Question 10

B cell deficiency is characterized by infections with “high-grade” (pus-producing) bacterial pathogens such as _______

Answer 10

Staph. Aureus

Question 11

Transient hypogammaglobulinemia children present with what type of infection?

Answer 11

gram positive bacterial infectionAlso this condition accounts for about 15% of chronic diarrhea

Question 12

When would you want to use IVIG?

Answer 12

When B cell function is deficient.

It is usually about 99% IgG and must be administered monthly.

Question 13

What might be a good treatment for SCID patients?

Answer 13

Bone marrow transplant or even better is purified stem cell transplant.

Question 14

An assay for C1inh inhibitor might be used to test what?

Answer 14

The functioning of complement in a patient.

Question 15

Describe the location of each of the 5 blocks in the lymphocyte development.

Answer 15

1. Blocks development of Lymphoid Stem Cell
2. Blocks Pre-B –> B cell
3. Blocks IgM to IgG switching
4. Blocks B-cell to Plasma Cell differentiation.
5. Abnormal development of the 3rd and 4th pharyngeal pouch (thymic lymphoid development problems)

Question 16

Describe the disorder of each of the 5 blocks in lymphocyte development.

Answer 16

1. SCID (Severe combined immunodeficiency disease)
2. X-linked (Bruton) Agammaglobinemia
3. X-Linked HyperIgM Syndrome
4. Common Variable Immunodeficiency (CVID)
5. DiGeorge Syndrome

SeXXy Brunettes are Hyper ‘Cause Dang

Question 17

What infections would you see in a pure B-cell deficiency?

Answer 17

“High grade” pyogenic (pus producing) infection from bacteria.

eg Staph Aureus

Question 18

What infections would you see in a pure T-cell deficiency?

Answer 18

Severe infections from intracellular pathogens such as viruses, certain bacteria, yeasts and fungi.

eg candida

Question 19

What are some of the clinical (physical) features found in DiGeorge Syndrome?

Answer 19

• Wide eyes (bug eyes)
• Down slanting eyes (Asian eyes)
• Fishmouth deformity
• Low set ears

Question 20

How common is selective IgA deficiency? What other syndromes are associated with IgA def?

Answer 20

1 in 500.

Where is IgA found? In the GI tract.
What’s one of the most common GI problems today?
Celiac Disease

Question 21

Nude mice (irradiated) may be used to model which human deficiency?

Answer 21

DiGeorge.

Irradiation kills T-cells.

Question 22

SCID may be both X linked and Autosomal Recessive. Which one is associated with an enzyme deficiency. Which enzyme is missing?
How do you treat it?

Answer 22

• Autosomal Recessive SCID
• Adenosine Deaminase
• Enzyme Replacement or Irradiated RBCs because Adenosine Deaminase is prevalent in blood.

Question 23

What transplants are associated with DiGeorge Syndrome?

Answer 23

Fetal Thymus or Thymic stromal cell transplant.

Question 24

What tests could you run to determine that a patient has a B-Cell Deficiency?

Answer 24

1. Serum Protein Electrophoresis

2. Antibody tests

Question 25

What tests could you run to determine that a patient has a T-Cell Deficiency?

Answer 25

1. Skin Test with recall Ag Panel

2. CD3, 4, 8 counts