14: Immunodeficiencies
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- 14.2: Autoimmune Disorders
- Autoimmune diseases result from a breakdown in immunological tolerance. The actual induction event(s) for autoimmune states are largely unknown. Some autoimmune diseases attack specific organs, whereas others are more systemic. Organ-specific autoimmune diseases include celiac disease, Graves disease, Hashimoto thyroiditis, type I diabetes mellitus, and Addison disease.
- 14.3: Superantigens
- Conventional antigens are only recognized by specific T4-cells having a TCR with a corresponding shape. Superantigens are unusual bacterial toxins that interact with exceedingly large numbers of T4-lymphocytes. Activation of very large numbers of T4-lymphocytes results in the secretion of excessive amounts of a cytokine called interleukin-2 (IL-2).
- 14.8: Primary Immunodeficiency
- Immunodeficiency results in an inability to combat certain diseases. A primary immunodeficiency is usually an immunodeficiency that one is born with. Conventional primary immunodeficiencies are rare recessive genetic defect in the immune responses that involved the development of B-lymphocytes, T-lymphocytes, or both and resulted in multiple, recurrent infections during infancy.
- 14.10: Secondary Immunodeficiency
- A secondary immunodeficiency is one in which a person is born with normal immune responses but some secondary factor or occurrence causes a decrease in immune responses. Causes of secondary immunodeficiencies include malnutrition, some viruses such as HIV, irradiation, cytotoxic drugs used in cancer chemotherapy, anti-inflammatory steroids, leukemias, aging, and removal of the spleen.
Thumbnail: Multiple plantar warts have grown on this toe.
