ABD Basic Science and Immunology 2

Question 1

Which cytokine is the principal driver of the Th2 immune axis implicated in atopic dermatitis?

Accepted Answer

IL-4

Answer

IL-4 is the signature Th2 cytokine central to atopic dermatitis pathogenesis and the target of dupilumab.

Question 2

A loss-of-function mutation in the FLG gene predisposes to atopic dermatitis by impairing production of which protein?

Accepted Answer

Filaggrin

Answer

FLG encodes filaggrin, essential for skin barrier integrity and hydration.

Question 3

Langerhans cells in the epidermis are best characterized by the presence of which cytoplasmic organelle?

Accepted Answer

Birbeck granule

Answer

Birbeck (tennis-racket) granules are the ultrastructural hallmark of Langerhans cells.

Question 4

Which immunoglobulin class is deposited in the dermal papillae in dermatitis herpetiformis?

Accepted Answer

IgA

Answer

Granular IgA deposits in dermal papillary tips are diagnostic of dermatitis herpetiformis.

Question 5

The type III hypersensitivity reaction responsible for cutaneous leukocytoclastic vasculitis is mediated primarily by:

Accepted Answer

Immune complex deposition

Answer

Type III reactions involve immune complex deposition in vessel walls triggering complement activation.

American Board of Dermatology (ABD) Practice Test