Primary Immunodeficiency, Autoimmune Disorders, Wound Healing

Question 1

DiGeorge Syndrome

Answer 1

developmental failure of third and fourth pharyngeal pouches
»»due to a 22q11 micro deletion

Presents with T-cell deficiency (lack of thymus)

Hypocalcemia (lack of parathyroid)

and abnormalities of the heart, great vessels, and face

Question 2

Severe Combined Immunodeficiency (SCID)

Answer 2

Defective cell mediated and humoral immunity

Etiologies include:

1. Cytokine Receptor Defects
   - cytokine signaling is necessary for proliferating and maturation of B and T cells
2. Adenosine Deaminase defeciency
   - ADA is needed for deamination of adenosine and deoxyadenosine for excretion as waste products; build up of adenosine and deoxyadenosine is toxic to lymphocytes
3. MHC class II deficiency
   - MHC class II is necessary for CD4+ helper T cell activation and cytokine production

Question 3

SCID increases the susceptibility to:

Answer 3

characterized by susceptibility to fungal, viral, bacterial, and protozoal infections including opportunistic infections and live vaccines

Question 4

Treatment for SCID

Answer 4

sterile isolation “bubble baby” and stem cell transplantation

Question 5

X Linked Agammaglobulinemia

Answer 5

complete lack of immunoglobulin due to disordered B cell maturation

pre and pro B cells cannot mature

due to mutated Bruton Tyrosine Kinase X linked

live vaccines (e.g. polio) must be avoided!

Question 6

Presentation of X Linked Agammaglobulinemia

Answer 6

presents after 6 mo. of life with recurrent bacterial, enterovirus (e.g. polio and cocksackievirus), and giardia lamblia infections

..maternal antibodies present during first 6 mo. of life are protective

Live Vaccines (e.g. Polio) must be avoided*

Question 7

Common Variable Immunodefeciency (CVID)

Answer 7

low immunoglobulin (due to B cell or Helper T cell defects)

increased risk for bacterial enterovirus, and giardia lamblia infections, usually in ** late childhood **

increased risk for autoimmune disease and lymphoma

Question 8

IgA Defeciency

Answer 8

low serum and mucosal IgA;
most common immunoglobulin defeciency

increased risk for mucosal infection, especially viral
however, most pts. are asymptomatic

Question 9

Hyper IgM Syndrome

Answer 9

elevated IgM
due to mutated CD40L (on helper T cells) or CD40 receptor (on B cells)

1. second signal cannot be delivered to helper T cells during B cell activation.
2. consequently, cytokines necessary for immunoglobulin class switching are not produced ***

[Low IgA, IgG, and IgE] result in recurrent pyrogenic infections (due to poor opsinization), especially at mucosal sites

Question 10

Wiskott-Aldrich Syndrome

Answer 10

[thrombocytopenia, eczema, recurrent infections]
(defect in humoral and cellular immunity)

bleeding is major cause of death

due to mutation of WASP gene; X linked

Question 11

Complement Deficiencies

Answer 11

C5-9 deficiencies - increased risk for Neissaria infection (N gonnorhea and N meningitidis)

C1 inhibitor deficiency - results in hereditary angioedema, especially periorbital edema and mucosal surfaces