Diseases

Question 1

Chronic Granulomatous Dz

Answer 1

Deficiency: NADPH oxidase
Mechanism: failure to generate oxygen free radicals for intracellular killing
ROS: infections w/ Catalase +ve organisms (Burkholderia, Serratia, Nocardia, Pseudomonas, Listeria, E. Coli, Staphylococus, Aspergillus, Candida, H. Pylori, H. Influenza)
Dx: Nitroblue tetrazolium negative (PMNs fail to turn blue)

Question 2

Leukocyte Adhesion Deficiency

Answer 2

Deficiency: CD18 absent from β2 integrins
Mechanism: PMNs unable to form abscess and pus bc they arent able to migrate to infected tissues
ROS: recurrent infections, delayed cord separation

Question 3

Chediak-Higashi

Answer 3

ROS: recurrent infections, albinism
Dx: granules in NK and phagocytes

Question 4

G6PD

Answer 4

Deficiency: G6PDH
ROS: hemolytic anemia d/t oxidative stress
Dx: bite cells, Heinz bodies

Question 5

Myeloperosidase deficiency

Answer 5

Def: MPO
ROS: no clinical sx’s

Question 6

Hyper IgM Syndrome

Answer 6

Deficiency: CD40L missing from Th cells
Dx: elevated IgM titers, no other isotopes, normal b and T cell numbers

Question 7

Selective IgA deficiency

Answer 7

Dx: usually occurs when pt has transfusion of matched donor blood that has IgA which the body decides is foreign

Question 8

Wiskott-Aldrich Syndrome

Answer 8

Defect: X-linked defect in WASp gene
Mechanism: defective cytoskeletal signaling
ROS: eczema, thrombocytopenia, variable immunodeficiency

Question 9

Ataxia Telangiectasia

Answer 9

Defect: ATM Protein kinase
Mechanism: pt is unable to repair dsDNA breaks
ROS: spinocerebellar degeneration, telangiectasias, diminished IgG, IgA and IgE

Question 10

IL-2 Receptor SCID

Answer 10

Defect: X-linked defect in γ chain of IL-2 receptor
ROS: lymphocytopenia, chronic diarrhea, lesions of mucosa, no response to mitogens

Question 11

ADA SCID

Answer 11

Deficiency: ADA in purine metabolism
Mechanism: accumulation of toxic products of purine metabolism in lymphocyte precursors

Question 12

Type I HS

Answer 12

Mechanism: IgE activating mast cells and basophils which degranulate
Mediators: histamine, heparin, prostaglandins, leukotrienes
Examples: allergic rhinitis (hay fever), systemic anaphylaxis, wheal and flare, Asthma, food allergies

Question 13

Type II HS

Answer 13

Mechanism: IgM and IgG against cell or tissue antigens (Ab-mediated)
Mediators: opsonization and phagocytosis, complement-mediated lysis and inflammation
Examples (cytotoxic type): hemolytic dz of the newborn, Rheumatic fever, Goodpasture syndrome (HLA-DRB1/DQB1), transfusion rxn, autoimmune TTP
Examples (non-cytotoxic): Graves, Myasthenia Gravis (HLA-B8), DM2

Question 14

Type III HS

Answer 14

Mechanism: circulating immune complexes
Mediators: deposition of ICs in small blood vessels activates complement and causes inflammation
Examples: Arthur’s rxn (tetanus booster), SLE (HLA-DRB1/DQB1), PSGN, Serum sickness, Polyarteritis Nodosa

Question 15

Type IV HS

Answer 15

Mechanism: Th1 cells and cytokines
Mediators: macrophage activation and granuloma formation, and CD8+ mediated killing w/ cytokine-driven inflammation
Examples: PPD test, contact dermatitis, RA (type 3 in serum, type 4 in joints; HLA-DRB1/DQB1), Hashimoto, MS (HLA-DRB1/DQB1), pernicious anemia, DM1 (HLA-DRB1/DQB1), Gillian-Barre, Crohn, Celiac (HLA-DQ2/DQ8)