Primary Immunodeficiency Flashcards
When would you expect susceptibility to start from a person with a B cell defect?
3-6 months after birth
Which organisms dominate when there is a B cell defect?
- Streptococci
- Staphylococci
- Haemophilus
- enteroviruses
When would you expect susceptibility to start from a person with a T cell defect?
From day 1
Which organisms dominate when there is a T cell defect?
Listeria, MTB, Toxo, fungi, protozoa
What do you call a B & T cell defect?
SCID - Severe combined immunodeficiency disease
-sick from birth
What are some B cell function tests?
- serum protein electrophoresis
- quantitation of specific Ig levels in blood
- check titers
- flow cytometry
What is the problem in X linked agammaglobulinemia?
Mutation in a signaling tyrosine receptor that is mandatory for growth and development of B cells [BLK]
-only pure B cell defect
Where can you find B-cells in X linked agammaglobulinemia?
- not in serum
- not in marrow or lymphoid tissue either
How would you treat X linked agammaglobulinemia?
IVIG
What is the problem in Hyper IgM syndrome?
mutation of CD40L on T cells
-most are x-linked
What is the treatment for Hyper IgM syndrome?
stem cell transplant
What is selective IgA deficiency?
- lacking IgA
- IgG and IgM levels are normal and compensate
- not associated with any specific infections
What is a clinical problem for selective IgA deficiency?
10% of patients may have anti-IgA antibodies which may cause anaphylactic reaction during blood transfusion or IVIG
What is EBV X-linked agammaglobulinemia?
- underlying defect is a mutation in signaling regulator of CD8 cells
- mutation activated by EBV infection of B cells
What causes the agammaglobulinemia in EBV X-linked agammaglobulinemia?
If patient survives the EBV, B cell depletion by cytotoxic T cells ensues
What is wrong in Common Variable Immunodeficiency?
-inability of B cell to differentiate to a plasma cell
Progression of Common Variable Immunodeficiency
- Infancy normal, symptoms begin after 2 years old
- Decreased IgG, IgA, and IgM first
- Then, symptoms signifying lack of T cells
- Then autoimmunity diseases
- Finally, lymphoma
Clinical Presentation of Common Variable Immunodeficiency
- B cells normal
- Lymph nones will have decreased germinal centers
Treatment of Common Variable Immunodeficiency
- IVIG until T cell defects start
- stem cell transplant
- surveillance for lymphomas
What is wrong in DiGeorge syndrome?
-chromosomal deletion in chromosome 22q11.2
-structural mutations in 3rd and 4th brachial punches
Infants very sick from birth with fungal infections
- cardiac problems tetralogy of ballot or pulmonary stenosis
- Face abnormal
- Absent parathyroid glands
- CATCH 22
Diagnosis of Thymic aplasia
- No thyme shadow on chest film
- decreased lymphoid tissue
What is wrong in SCID?
- multiple sites of mutation: Adenosine Deficiency deficiency, IL2 R, JAK, Rag 1, 2
- TRECs decreased or absesnt
Treatment of SCID
- stem cell transplant or gene insertion
- if ADA deficiency, then enzyme replacement therapy
What is molecularly wrong in Wiskott-Aldrich syndrome?
X-linked recessive mutation of WAS gene
-decreased IgM and inability to make antibody to polysaccharides
