Jitt # 7 APECED

Question 1

APECED

Answer 1

Autoimmune Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy (Also known as APSI); human autosomal recessive disease; Mutation in AIRE (which is not encoded by MHC genes);

Question 2

What cell types play the most important role in negative selection?

Answer 2

Bone-Marrow derived DCs and Macrophages; Thymic medullary epithelial cells also play a role.

Question 3

Symptoms of APECED

Answer 3

Decreased growth; inadequate growth hormone; high levels of TSH; antibodies against endocrine glands, liver, and skin; increased susceptibility to infection with candida albicans; abnormalities in skin, teeth and fingernails;

Question 4

Which cytokines do patients with APECED have antibodies against?

Answer 4

IL-17A, IL-17E, and IL-22. These are important cytokines in controlling fungal infections.

Question 5

Negative selection

Answer 5

Single Positive thymocytes who bind to antigens in the thymic medulla with high avidity undergo apoptosis.

Question 6

Central Tolerance

Answer 6

Induced when developing
lymphocytes encounter self antigens in the
primary or generative lymphoid organs (thymus
and bone marrow)

Question 7

Peripheral Tolerance

Answer 7

Induced when mature lymphocytes encounter self antigens in peripheral tissues.

Question 8

What is the fate of thymocytes that bind with intermediate affinity?

Answer 8

They become Treg. Regulatory T Cells.

Question 9

Generation of Treg

Answer 9

Occurs in the thymus; Thymocytes bind with intermediate affinity; Transcription factor FoxP3 upregulated; Treg moves to the periphery and inhibits self reactive T cells.