Miscellaneous

Question 1

Acute-phase reactants (enumerate)

Answer 1

1- Positive (upregulated)
- C-reactive protein
- Ferritin
- Fibrinogen
- Hepcidin
- Serum amyloid A
2- Negative (downregulated)
- Albumin
- Transferrin

Question 2

Type I hypersensitivity reaction mechanism and examples

Answer 2

• Free antigen cross-links IgE on presensitized mast cells and basophils triggering immediate release of vasoactive amines
• Allergic rhinitis (hay fever), Systemic anaphylaxis, food allergies, wheal and flare, and asthma

Question 3

Type II hypersensitivity reaction mechanism and examples

Answer 3

• IgM or IgG bind to fixed antigens on “enemy” cell leading to cell destruction by MAC formed by antibody and complement. 1) opsonization and phagocytosis 2) complement and Fc-receptor mediated inflammation 3) Antibody mediated cellular dysfunction
• Cytotoxic (autoimmune hemolytic anemia [HDNB], acute rheumatic fever, Goodpasture syndrome, transfusion reaction, autoimmune thrombocytopenic purpura, erythroblastosis fetalis, bullous pemphigoid, pemphigus vulgaris, Guillain-Barre syndrome), Non-cytotoxic (Myasthenia gravis, Graves disease, Type II dibetes, pernicious anemia)

Question 4

Type III hypersensitivity reaction mechanism and examples

Answer 4

• Antigen-antibody (IgG) complexes activate complement, which attracts neutrophils which release lysosomal enzymes
• SLE, PSGN, Arthus reaction, serum sickness, Polyarteritis nodosa

Question 5

Type IV hypersensitivity reaction mechanism and examples

Answer 5

• Sensitized T cells encounter antigen and then release cytokines (leads to macrophage activation)
• Tuberculin test, contact dermatitis, Hashimoto thyroiditis, multiple sclerosis, rheumatoid arthritis, type I diabetes, Guillain-Barre syndrome, Celiac disease, Crohn disease

Question 6

Blood transfusion reactions (enumerate)

Answer 6

• Allergic reaction (Type I)
• Anaphylactic reaction
• Febrile non-hemolytic transfusion reaction (Type II)
• Acute hemolytic transfusion reaction (Type II)

Question 7

After blood transfusion; urticaria, pruritis, wheezing and fever (Diagnosis?!!)

Answer 7

Allergic reaction

Question 8

After blood transfusion; dyspnea, bronchospasm, hypotension, respiratory arrest and shock (Diagnosis?!!)

Answer 8

Anaphylactic reaction

Question 9

After blood transfusion; fever, headaches, chills and flushing (Diagnosis?!!)

Answer 9

Febrile non-hemolytic transfusion reaction

Question 10

After blood transfusion; fever, hypotension, tachycardia, flank pain, hemoglobinuria and jaundice (Diagnosis?!!)

Answer 10

Acute hemolytic transfusion reaction

Question 11

Bacterial infections in individuals with decreased T cells

Answer 11

Sepsis

Question 12

Bacterial infections in individuals with decreased B cells

Answer 12

Encapsulated bacteria

Question 13

Bacterial infections in individuals with decreased granulocytes

Answer 13

• Staphylococcus
• Burkholderia cepacia
• P. aeruginosa
• Serratia
• Nocardia

Question 14

Bacterial infections in individuals with decreased complement

Answer 14

• Encapsulated species with early component deficiencies

- Neisseria with late component (MAC) deficiencies

Question 15

Viral infections in individuals with decreased T cells

Answer 15

• CMV, EBV, JCV, VZV

- Chronic infection with respiratory/GI viruses

Question 16

Viral infections in individuals with decreased B cells

Answer 16

• Enteroviral encephalitis

- Polio (live vaccine contraindicated)

Question 17

Viral infections in individuals with decreased granulocytes

Answer 17

None

Question 18

Viral infections in individuals with decreased complement

Answer 18

None

Question 19

Fungi/parasites infections in individuals with decreased T cells

Answer 19

• Candida (local)

- PCP

Question 20

Fungi/parasites infections in individuals with decreased B cells

Answer 20

GI giardiasis (no IgA)

Question 21

Fungi/parasites infections in individuals with decreased granulocytes

Answer 21

• Candida (systemic)

- Aspergillus

Question 22

Fungi/parasite infections in individuals with decreased complement

Answer 22

None

Question 23

Wide-spread thrombosis of graft vessels leading to ischemia and necrosis (Diagnosis and pathogenesis?!!)

Answer 23

• Hyperacute transplant rejection

- Pre-existing recipient Abs that react to donor Ags (Type II), activate complement

Question 24

Vasculitis of graft vessels with dense interstitial lymphocytic infiltrate (Diagnosis and pathogenesis?!!)

Answer 24

• Acute transplant rejection
• Cellular: CD8+ T cells activated against MHCs (type IV). Humeral: recipient Abs that react to donor Ags (formed after transplant)

Question 25

Lymphocytic infiltration of graft with proliferation of vascular smooth muscle, parenchymal atrophy, interstitial fibrosis. dominated by arteriosclerosis (Diagnosis and pathogenesis?!!)

Answer 25

- Chronic transplant rejection - CD4+ T cells respond to recipient APCs presenting donor peptides, including allogeneic MHC. both cellular and hymoral component (Type II and IV) - Examples are bronchiolitis obliterans, accelerated atherosclerosis, chronic graft nephropathy, vanishing bile duct syndrome

Question 26

After graft maculopapular rash, jaundice, diarrhea, and hepatosplenomegaly (Diagnosis and pathogenesis?!!)

Answer 26

- Graft-versus-host disease - Grafted immunocompetent T cells proliferate in the immunocompromised host and reject host cells with "foreign" proteins resulting in severe organ dysfunction (Type IV) - Potentially beneficial in bone marrow transplant for leukemia (graft-versus-tumor effect)