Primary Immunodeficiency Disorders Flashcards Preview

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Flashcards in Primary Immunodeficiency Disorders Deck (24):
1

What is the pathogenesis of X-linked SCID?

mutation in gamma chain of IL-2 receptor

2

What is the common feature in all SCID?

Absent/non-functional T cells

3

What is the newborn screening test of SCID?

TRECs -- non-replicating pieces of DNA in naive T cells generated when making a TCR; number decreased in all SCID and T cell lymphopenia

4

What is the main gene affected in DiGeorge Syndrome?

TBX1

5

CATCH-22 Mnemonic for DiGeorge

Cardiac Defects
Abnormal facies (microagnathia, low set ears, fish-shaped mouth)
Thymic hypoplasia
Cleft palate
Hypocalcemia
22nd chromosome

6

Developmentally, where is the defect in DiGeorge syndrome?

1st-6th pharyngeal pouches

7

Who do you recommend testing for 22q/DS??

ALL infants with significant heart defects
Unexplained lymphopenia

8

What is the common presentation of XLA?

Boy
No B cells
Recurrent pulmonary infections

9

What genetic mutation is present in XLA?

Mutations in Bruton's Tyrosine Kinase Gene (Btk) results in failure in the differentiation of B cells --> usually results in absence of Btk protein

10

What infections are common in individuals with CVID?

RTI/GI; pulmonary disease-- bronchiectasis and interstitial lung disease

11

Common non-infectious complications of CVID

Lung disease
Neoplasia (B cell lymphoma, gastric carcinoma)
Autoimmunity
GI disease
Liver disease

12

What constitutes a CVID diagnosis?

Low IgG AND low IgA and/or low IgM

13

What is the most common Ab deficiency?

IgA deficiency

14

What constitutes IgA deficiency diagnosis?

Low IgA -- normal IgG and IgM

15

What causes false positive results with IgA deficiency?

Heterophile antibodies: antibodies that recognize an antigen different than the antigen that originally induced the Ab response

16

What is the main clinical finding in individuals with specific antibody deficiency?

abnormal specific antibody response to immunization (especially PS antigens)

17

What is the pathogenesis of CGD?

An absence of respiratory burst in neutrophils and monocytes -- impaired bactericidal killing; defect in NADPH oxidase

18

What is one presentation that should be considered CGD until proven otherwise?

Hepatic abscess without obvious source in young child

19

What is unique about mothers of boys with X-linked CGD?

Random X chromosome inactivation occurs so that 50% of the mother's neutrophils express normal NADPH oxidase and 50% express the defective NADPH oxidase

20

What are the genetic mutations in LAD-1 and LAD-2?

LAD-1 mutation in common gamma chain
LAD-2 mutation in GDP-fructose transporter which leads to an absence of sialyl LewisX

21

Will leukocyte count be high or low in leukocyte adhesion deficiency?

High -- because there will not be any adhered to endothelium

22

How do patients with LAD-1 present?

Recurrent pyogenic infections, delayed umbilical cord detachment, leucocytosis, inability to form pus

23

Those with late complement deficiency are highly susceptible to what bug?

Neisseria

24

What is the most common complement deficiency?

C2, autosomal recessive