2-Immunodeficiency

Question 1

immunodeficiencies

definition

Answer 1

lack of an immune system or failure of components that inc susceptibility to infection
-primary/congenital OR secondary/acquired

Question 2

acquired/secondary immunodef

Answer 2

from AIDS, drugs for transplantation or cancer, malnutrition

Question 3

affected components

Answer 3

• defect humoral imm = infection extracelluar bacteria
• CMI impaired = infection virus and intracell
• if both then infections with all classes microorganisms

Question 4

cancers of viral etiology

Answer 4

EBV > lymphomas
HPV > skin cancers

T cell deficiencies = inc risk bc less immunosurveillance

Question 5

B cell deficiency characteristics

Answer 5

• dec serum Ig levels
• normal skin test rxn
• lymphoid tissue germinal centers dec or absent
• extracellular bacteria susceptible

Question 6

T cell deficiency characteristics

Answer 6

-normal or dec Ig levels
-dec skin test rxn
-normal follicles + dec paracortical region of lymphoid tissue
-virus, intracell bact, fungi susceptible

Question 7

X linked agammaglobulinemia

Answer 7

aka bruton’s agammaglobulinemia
-no mature B cells so little Ig
-block in B cell maturation bc normal pre-B levels in marrow
-B cell tyrosine kinase mutation
-males only, female carriers don’t manifest disease bc other X is normal
-onset 6 mo to 1 yr, mean dx 3 yr olds
-pyogenic bacteria suscept

Question 8

X linked agammaglobulinemia

diagnosing

Answer 8

absence of circulating B lymphs via flow cytometry but after 6-9 mo bc maternal antibodies

controlled by monthly injections of pooled gamma globulin + antibiotic therapy but NOT vaccines bc no antibody resp

Question 9

common variable immunodeficiency

Answer 9

mature B cells not diff into plasma cells so dec antibodies
-males and females suscept to recurrent bacterial infection
-progressive pulmonary insufficiency

Question 10

selective IgA deficiency

Answer 10

most common immunodef
-asymptomatic but maybe inc infections of mucosal sites
-IgM can compensate
-IgE anti-IgA so severe/fatal anaphylatic rxn if given plasma with IgA

Question 11

selective IgA deficiency

diagnosis

Answer 11

severely dec IgA levels, others are normal
-B cells with surface IgA but no diff into plasma cells
-T cells still intact
-maybe inc allergy, GI tract disease, autoimmune

only treat with antibiotics NO antibodies/gamma globulin

Question 12

hyper IgM syndrome

Answer 12

overabundance of IgM+ lack other isotypes

either x linked or type 2

Question 13

x linked hyper IgM syndrome

Answer 13

inherit def of CD40L on T cells so CD40 on B cells not engaged and no isotype switching

Question 14

hyper IgM type 2 syndrome

Answer 14

inherit mutation in gene activation induced cytidine deaminase so prevents isoype switching
-reasons unknown

Question 15

DiGeorge Syndrome

Answer 15

aka congenital thymic hypoplasia
-def of T cells bc small or no thymus
-poor CMI vs virus and fungi
-maternal alcoholism and chromosome 22q11 deletion
-treat with age bc of extrathymic maturation

Question 16

DiGeorge symptoms

Answer 16

-facial features distinct
-parathyroid glands
-heart vessles
bc from third and fourth pharyngeal pouches during embryogenesis

-immunoglobulin levels near normal but T cells severly dec

Question 17

SCID

Answer 17

fail of B and T cells to dev from bone marrow stem cells so little/no humoral OR CMI = death from overwhellming infection
-live viral vaccines can be fatal

also called swiss type agammaglobulinemia

Question 18

causes of SCID

Answer 18

1. autosomal recessive - ADA adenosine deaminase def so toxic metabolites destroy lymphs
2. RAG1/2 def- failure of VDJ rearrange, no recombinase in immunoglobulins and TCR genes
3. x linked SCID- mutation in gene for y chain for cytokine receptors for IL2,4,7,9,15 so lymphs not dev properly

Question 19

SCID treatment

Answer 19

bone marrow transplant but gene therapy used to transfect autologous bone marrow stem cells with ADA

Question 20

chronic granulomatous disease

Answer 20

recurrent bacterial infections from early childhood
-NADPH def so neutros not make superoxide for respir burst

bone transplant or gene therapy treat or antibiotic therapy but still fatal

Question 21

myeloperoxidase deficiency

Answer 21

dec or absent myeloperoxidase so no hypochlorous acid for antibacterial and antifungal

compensatory mechanisms so no inc suscept but still fungal

Question 22

chediak higashi syndrome

Answer 22

low yield

Question 23

leukocyte adhesion deficiency

Answer 23

defect in beta chain of LFA-1 and Mac-1 adhesion moles so neutros not adhere to endo cells for extravasation
-recurrent bact/fungal infections
-wound healing problems
-extremely high WBC levels/leukocytosis

Question 24

leukocyte adhesion deficiency

treatment

Question 25

neutropenia

Answer 25

low yield
either

Question 26

wiskott-aldrich syndrome

Answer 26

1. immunodef
2. eczema
3. thrombocytopenia, lack platelets

no WASP protein so cells not traffic to sites of inflamm and B/T cells not interact

Question 27

ataxia telangiectasia

Answer 27

-loss ability to coord muscles
-vascular lesions
-inc incidence tumors

defect in ATM