Immune Deficiency Flashcards
Normal variation in immune function (elderly)
Thymic involution
Fewer naïve T cells – dependent on memory T cells
Reduced ability for T cell expansion
Reduced B cell development and diversity
-Diminished response to vaccination
More dependent on innate immunity
-But reduced function of pattern recognition receptors and superoxide killing
Environmental factors resulting in secondary immune deficiency
Malnutrition, trauma and burns
Diseases that can result in secondary immune deficiency
Infection with HIV, diabetes, renal failure, asplenia, maligancy
Drugs that result in secondary immune deficiency
Immunosuppressive, antirheumatics, anitepileptics
HIV
Virus binds to CD4+ cells to gain entry. Immune deficiency due to reduced CD4+ T helper cell function: reduced B cell, CD8+ and macrophage activity
Protein-calorie malnutrition associated ID
Immune defenses require energy
Proteins: cytokines, acute phase proteins, chemokines etc
Zin related ID
Essential for proliferating cells
Deficiency = PMN, NK, monocyte, B and T cell impaired function
Iron related ID
Enzymes within cellular function and metabolic pathways
Deficiency = impaired innate immune function – toxic oxygen species
Why does malignancy result in reduced immune function
Immunosuppressive molecules (IL-10, TGF-beta, VEGF, increase T reg function, myeloid suppressor cells) are secreted from tumours
Lymphoma
Reduce or loss of MHC I expression in cancerous cells
Downregulation of MHC II genes within B cell NHL
Markers that inhibit cytotoxic T cell and NK killing
Glucocorticoids
Anti-inflammatory –
Activate lipocortins: reduce phospholipase A2 and arachidonic acid release
Alter transcription of enzymes needed for inflammation
Ciclosporin
Calcineurin inhibitor
Reduced inflammatory cytokine release from T cells
Rituximab
Binds to CD20 (B lymphocytes)
Allows NK and complement mediated apoptosis
