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Flashcards in Immune deficiencies Deck (18):
1

2 T cell deficiencies, and their consequences

Bare Lymphocyte Syndrome,
DiGeorge's Syndrome.
More viral and fungal infections, and early malignancies.

2

B cell deficiencies (4)

Bruton's agammaglobulinaemia,
Common variable immune deficiency,
Selective IgA deficiency,
Hyper-IgM syndrome.
More bacterial infections, and some toxins.

3

Phagocyte deficiencies (4)

Kostmann syndrome,
Leukocyte adhesion defiency,
Chronic granulomatous disease,
Cyclic neutropaenia.
More bacterial and fungal infections, more abscesses.

4

Bare Lymphocyte Syndrome

No HLA in thymus, so T cells. (Type 1 lacks MHC I, so no CD8, and 2, II (CD4).)
Type 2 more common.
B cell class switch needs CD4, so less IgA and IgG.
Associated with Primary Sclerosing Cholangitis.
Unwell by 3 months old.

5

DiGeorge's Syndrome

Cardiac abnormality (tetralogy),
Abnormal face,
Thymic aplasia,
Cleft palate/lip and low set ears,
Hypocalcaemia / hypoparathyroidism.
22q11.2 deletion (75% sporadic).
3rd and 4th pharyngeal pouches don't develop.
Tx: thymus transplant.

6

Bruton's agammaglobulinaemia

X-linked Tyrosine kinase defect.
No mature B cells, so no Abs.
Symptoms after 3-6 months old.

7

Common Variable Immune Deficiency

Low IgG, IgA and IgE.
Many genetic causes, including MHC III deficiency.
Failure to thrive, recurrent infections, autoimmune and granuomatous disaeases.

8

Selective IgA Deficiency

Affects 1 in 600 Cauasians, 70% asymptomatic.
Recurrent gastro and respiratory infections.

9

Hyper-IgM Syndrome

Xq26 (boys). Defect in CD40, CD40L, CD154 or AICDA.
Baby boys with recurrent bacerial infections (Pneumocytis carinii) and FTT.
T cells can't communicate with B cells, so no class switching, so IgM only.
Less lymphoid tissue: no germinal centre development.
Risk of autoimmunity and malignancy.

10

Tx for B cell deficiencies

Ig replacement,
?BMT.
Vaccines in IgA def only.

11

Severe Combined Immune Deficiency

Lymphoid precursor problem:
- X-linked: IL2-Receptor mutn;
- Adenosine deaminse deficiency;
- Adenylate kinase 2 malfunction: Reticular dysgenesis.
Recurrent infections (bubble babies), FTT, persistent diarrhoea, early death.
T cells low, B cells low or normal, Abs low.
Tx: BMT.

12

Kostmann Syndrome

Severe congenital neutropaenia.
Autosomal recessive, HAX-1.
Dx: Chronically low neut, arrested neut precursor maturation in BM.
Tx: G-CSF, Abx, ?BMT.

13

Leukocyte Adhesion Deficiency

No Leukocyte adhesion markers.
- LAD 1: deficiency of beta 2 integrin subunit (CD18);
- LAD 2: much rarer. severe growth restriction, mental retardation.
Life threatening neonatal bacterial infections.
High neutrophil count. Delayed umbilical cord separation.
Tx: BMT.

14

Chronic Granumlomatous Disease

Usually X-linked, many mutns.
Failure of oxidative killing:
- negative Nitro-Blue Tetrazolium as no H2O2 (stays yellow);
- dihydrorhodamine (DHR) not oxidised to rhodamine.
Pneumonia, abscesses, suppurative arthritis.
Can resist catalase -ve bacteria.
Tx: trimethorpim, itraconazole, interferon, ?SCT.

15

Cyclic neutropaenia

Every 3 weeks, a few days of neutropaenia.
ELA1 mutns.
Tx: G-CSF.

16

Reticular Dysgenesis

Most severe form of SCID (adenylate kinase 2).
Missing all blood cells but RBCs.
Fatal v early unless BMT.

17

Wiskott-Aldrich Syndrome

Low platelets, so brusing and bloody diarrhoea.
Low IgM, so recurrent infections.

18

Cytokine deficiencies

Can be low in IFN-g, IFN-g-Receptor, IL-12 or IL-12-Receptor.
No signalling between T cells and macrophages, so no TNF or NADPH oxidase.
Salmonella, and TB (inclusing atypical Mycobacteria).
Can't form granulomata.