Lecture 14.3 Autoimmune Diseases

Question 1

Autoimmune Polyendocrinopathy Candidiasis Ectodermal Dystrophy (APECED)

Answer 1

This disease results from a genetic deficiency in the gene that encodes AIRE, which resides in the thymus. It’s a transcription factor that codes for a bunch of proteins that are used during T-cell negative selection. Lack of those proteins means that self-reactive T-cells are not recognized and removed from the T-cell repertoire.

Presentation: underproduction of hormones, alopecia totalis, and diarrhea.

Question 2

Immune Dysregulation, Polyendocrinopathy, Enteropathy, X-linked Syndrome (IPEX)

Answer 2

This is a genetic deficiency of FoxP3 that results in lack of T-regs, and therefore lack of self-reactive policing activity.

Presentation: watery diarrhea, eczematous dermatitis, type I diabetes.

Question 3

Autoimmune Lymphoproliferative Syndrome (ALPS)

Answer 3

Occurs from a mutation that results in no expression of functional Fas, Fas-ligand, or caspase 10. Immune cells do not undergo apoptosis after an immune response, resulting in overpopulation of secondary lymphoid tissues.

Presentation: lymphadenopathy and splenomegaly, anemia, thrombocytopenia, and a large number of double negative T-cells.

Treatment: Immunosuppression