SCID

Question 1

Hyper IgM

Answer 1

All have viral, bacterial, fungal infectons

different types

X-linked Hyper IGM:

• CD40L gene on X chain defective
• lack of cd40 expression of activated T cells, cant co-activate B cells and macrophages
• results in no isotype switching, but high IgM
• spleen doesnt show GC
• normal B-T cell development, impaired humoral and cellular defenses

Type 2 hyper IgM (autosomal recessive)

• AID defect
• mutation in gene encoding activation induced cytidine deaminase (AID)
• b cells fail to isotype switch and have reduced somatic recombination
• Aid impt for isotype swicthing and somatic recomb

TYPE 3 hyper IgM:
- mutation in CD40

Question 2

Zap 70

Answer 2

disrupts t cell signaling
scid like defects
increase in opportunistic infections

Question 3

Bare Lymphocyte Syndrome

Answer 3

you have B+T+
defect in expression of class 1 or class 2 MHC
-impared antigen presentation and selection of t cells

BLS I: no CD8, mutation in Tap 1 and 2. MHC 1
BSL II: no CD4, mutation in class II trans-activator (CIITA)--uses CLIP which stays in as invariant chain (later there is a peptide exchange MHC II

chronic respiratory infections and ulcers

Question 4

Omenn Syndrome

Answer 4

T+ B-
MUTATION in Rag 1 +2, partial Rag activity
massive skin/ GI infiltrates by eosinophils
lack functional T cells, have some and are inflamatory
no b cells found
similar features to GVHD (inflamation, edema, rash, diarrhea)

Question 5

RAG deficiency

Answer 5

mutation in Rag 1 +2 –> absence of T and B cells

new born screening for this

Question 6

Adenosine Deaminase Deficiency

Answer 6

results in accumulation of toxic metabolites
dATP–> results in absence of B, T and NK cells
autosomal ressive
-gene therapy

Question 7

Autosomal Recessive SCID

Answer 7

(T- B+)
same presentation as x linked
mutation in JAK3 kinase (transmits signal from y chain of receptors)

Question 8

X-linked SCID

Answer 8

(T- B+)

same presentation as autosomal recessive scid

mutation in yc chain subunit for Il-2/4/7/9/15

no NK development