Aani Immuno: Primary Immune Deficiencies Flashcards
What type of antibodies do immature B cells produce?
IgM only
How are IgG, IgA and IgE Abs produced?
Following CD4 cells + B cells class switch
What are the types of Primary Immune Deficiencies?
T cell
B cell
Phagocyte
Complement
What are the types of Deficiencies that affect T cells?
Bare Lymphocyte Syndrome
DiGeorge Syndrome
SCID (mixed B and T)
What are the types of Bare Lymphocyte Syndrome?
Type 1 and Type 2.
Type 1 = Low MHC Class 1
Type 2 = Low MHC Class 2
Which type of Bare Lymphocyte Syndrome is more common?
Type 2
Describe the cells of Type 2 Bare Lymphocyte Syndrome?
It would have NORMAL CD8 and B cells. But absent CD4 cells.
This means that the germinal centre reaction between B cells and CD4 cannot take place so IgM can be made by B cells but IgG/IgA and IgE cannot be made.
Which condition is associated with Bare Lymphocyte Syndrome?
Sclerosing Cholangitis
What is the chromosomal defect in DiGeorge Syndrome?
22q11.2 deletion
What happens in DiGeorge Syndrome (in terms of T cells)?
Impaired development of 3rd and 4th pharyngeal pouch, absent thymus so T cells cannot mature = low mature T cells.
What are the clinical features of DiGeorge Syndrome?
CATCH 22 Cleft palate Abnormal facies - low ears, high forehead Thymic aplasia Cardiac abnormality - tof Hypoparathyroid
CHD (because aortic arch is alo made from 3/4 pharyngeal pouch)
Treatment of DiGeorge Syndrome?
Infection prophylaxis
Thymus transplant
Ig replacement
Treatment of Bare Lymph Syndrome type 2?
BMT
Infection prophylaxis
Ig replacement
What are the types of B Cell primary Immune Deficiencies?
Bruton's Agammaglobulinaemia Common Variable Immune Deficiency Selective IgA deficiency Hyper IgM Syndrome SCID (mixed B and T cell)
Which Igs are missing in Bruton’s?
ALL because no B Cells
Which Igs are missing in Common Variable Immune Deficiency?
IgA, IgG and IgE (basically the 3 ones that mature B cells are needed to make)
Which Igs are missing in Selective IgA deficiency?
IgA lol
What causes the Ig defect in Common Variable Immune Deficiency?
Failure of B cell differentiation
How to tell the diff between Common Variable Immune Deficiency and Brutons?
Common Variable will have IgM. Brutons wont have any Ig.
Which is the most common B Cell Immune Deficiency?
Selective IgA deficiency