Immunology

Question 1

Which immunoglobulin can cross placenta? What are some other fun facts about it?

Answer 1

IgG Main antibody in 2° (delayed) response to an antigen. Most abundant isotype in serum. Fixes complement, provides infants with passive immunity, opsonizes bacteria, neutralizes bacterial toxins and viruses.

Question 2

Passive Immunity is achieved by

Answer 2

• Receiving preformed antibodies
• IgA in breast milk, maternal IgG crossing placenta, antitoxin, humanized monoclonal antibody

After exposure to Tetanus toxin, Botulinum toxin, HBV, Varicella, or Rabies virus,

unvaccinated patients are given preformed antibodies (passive)—

“To Be Healed Very Rapidly”

Question 4

Monoclonal antibodies that antagonize the IL-2 receptor

Answer 4

Daclizumab, basiliximab

used in kidney transplant as rejection prophylaxis

Question 5

Rheumatoid Factor

Answer 5

IgM antibody that targets IgG Fc region

+ 80% of RA cases

Can also do anti-CCP (more specific)

Question 6

Chronic mucocutaneous candidiasis

Answer 6

T-cell dysfunction

Noninvasive Candida albicans infections of skin and mucous membranes.

Question 7

Hemoptysis, Hematuria, smooth linear pattern on IF

Answer 7

Goodpasture Syndrome (type II hypersensitivity rxn)

-antibasement membrane antibodies

Question 8

CD marker for Naturak Killer Cells

Answer 8

CD16 (on the road at 16, new drivers are natural killers)

Question 9

CD4 Levels corresponding to particular opportunistic infections in HIV pts

1. CD4 <500
2. CD4 < 200
3. CD4 < 100
4. CD4 < 50

Answer 9

1. CD4 <500 Herpes Simplez, Herpes Zoster, Oral Thrush, EBV, HPV, Kaposi Sarcoma
2. CD4 < 200 Pneumocystis jirovecii, JC Virus (progressive multifocal leukoencephalopathy), Toxoplasmosa Gondii, Dementia
3. CD4 < 100 EBV, CMV, Candida Albicans, Cryptococcus neoformans, Aspergillis
4. CD4 < 50 Mycobacteria Avium (MAC)

Question 10

Measles (rubeola) virus

Answer 10

3 C’s of measles: Cough Coryza (inflammation of the mucous membrane in the nose), Conjunctivitis

Koplik spots, followed
by a maculopapular rash that starts at
the head/neck and spreads downward. Lymphadenitis with Warthin-Finkeldey giant cells (fused lymphocytes) in a background of paracortical hyperplasia

Question 11

These symptoms are associated with what syndromes given a history of recurrent S. Aureus infections?

1. Cafe au lait spots
2. Cleft Palat
3. Papalovesicular Dermatitis
4. Spider Angiomas
5. Thrombocytopenia

Answer 11

1. Cafe au lait spots: Neurofibromatosis Type 1, McCune-Albright syndrome (if unilateral)
2. Cleft Palate: DiGeorge (thymic dysplasia)
3. Papalovesicular Dermatitis: Job syndrome (failure of helper T cells to produce INF-y)
4. Spider Angiomas: Ataxia Telangectasia
5. Thrombocytopenia: Wiskott Aldrich Syndrome (high IgA, high IgE, normal IgG, low IgM)

Question 12

Complement disorders

C1 esterase inhibitor deficiency

C3 deficiency

C5–C9 deficiencies

DAF (GPI-anchored enzyme) deficiency

Answer 12

C1 esterase inhibitor deficiency: Causes hereditary angioedema (Family comes first). ACE inhibitors are contraindicated.

C3 deficiency: Increases risk of severe, recurrent pyogenic sinus and respiratory tract infections; susceptibility to type III hypersensitivity reactions.

C5–C9 deficiencies: Terminal complement deficiency increases susceptibility to recurrent Neisseria bacteremia (terminal/end stage gonorrhea)

DAF (GPI-anchored enzyme) deficiency: Causes complement-mediated lysis of RBCs and paroxysmal nocturnal hemoglobinuria.

Question 13

Bacterial endocarditis actute vs subacute and the overall symptoms

Answer 13

Acute—S. aureus (high virulence). Large vegetations on previously normal valves C . Rapid onset.

Subacute—viridans streptococci (low virulence). Smaller vegetations on congenitally abnormal or diseased valves. Sequela of dental procedures. Gradual onset.

Symptoms: Fever (most common), new murmur, Roth spots (round white spots on retina surrounded by hemorrhage), Osler nodes (tender raised lesions on finger or toe pads), Janeway lesions (small, painless, erythematous lesions on palm or sole), glomerulonephritis, septic arterial or pulmonary emboli, splinter hemorrhages on nail bed

Question 14

DiGeorge Syndrome in regards to pharyngeal development

Answer 14

chromosome 22q11 deletion. Aberrant development of 3rd and 4th pouches –> T-cell deficiency (thymic aplasia, 3rd) and hypocalcemia (failure develop parathyroid; superior 3rd, inferior 4th)

-The paracortex of the lymph node houses T cells and is not well developed in DiGeorge Syndrome

Question 15

A negative nitroblue test signifies what?

Answer 15

• verifies diagnosis of Chronic Granulomatous Disease, a deficiency in NADPH oxidase
• This negative results indicates a lack of ROS
• CGD predisposes to an increased susceptibility of catalase + organisms

Question 16

-Three most common bacterial infections associated with infleunza (pulmonary infiltrates, usually on older pt who was not vaccinated)

Answer 16

1. S. Aureus
2. Strep pneumo
3. H Influenzae