09.17.18 Acquired Immunodeficiency Flashcards
Defects in the immune system not arising from genetic abnormalities, but from infections, nutritional deficiencies, other medical conditions/treatments, or external stimuli
Acquired Immunodeficiency
What are the causes of acquired immunodeficiency?
- Disorders of biochemical homeostasis
- Disorders of protein loss
- Trauma/burns
- Environmental exposures
- Hyposplenism
- Life events (pregnancy/stress)
- Infection
How does diabetes mellitus affect the immune system?
- Decreased neutrophil function
- Poor peripheral circulation (increases skin ulceration)
- Infectious complication = disseminated candidiasis/yeast
What are the disorders of biochemical homeostasis?
- Diabetes mellitus
- Dialysis and uremia
- Liver cirrhosis
How can hemodialysis affect immune system?
- Reduced T cell function and Ig production
2. Compromised neutrophil/dendritic function
How can chronic ambulatory peritoneal dialysis (CAPD) affect the immune system?
no sig systemic immune defects BUT
- Peritoneal neutrophil function depressed due to removal of opsonic factors (Ig and complement) with the dialysate
How can cirrhosis affect the immune system?
- Liver dysfunction= risk for bacterial sepsis and peritonitis bc high glucocorticoids and low complement (complement made in liver)
What are disorders of protein loss?
- Nephrotic Syndrome
- Peritoneal dialysis
- Protein-losing enteropathies
Any disease process w/ increased protein loss can lead to _____
Hypogammaglobulinemia
- Kidney disease with significant protein loss
- Low Igs
- infection from encapsulated bacteria
Nephrotic Syndrome
Includes inflammatory bowel disease, celiac disease, intestinal lymphangiectasia
Protein-losing enteropathies
How does trauma affect the immune system?
Massive release of inflammatory cytokines
- Greater immune suppression that mechanical trauma
- disrupts large area of nonspecific defense (skin)
Burns
What are examples of environmental exposures?
- Ionizing radiation
- UV radiation
- Toxic chemicals
How can ionizing radiation affect the immune system?
- Damage DNA –> cell division –> impaired immune function
- B cell low; T cell numbers recover more rapidly
- Primary antibody response diminished
- Phagocytic cells= radiation resistant
- Nodes/spleen affected
- Damaged local barriers= increased susceptibility to infection
How can UV radiation affect the immune system?
Chronic sun exposure leads to diminished function of all skin resident immune cells
Numerous environmental chemicals incriminated in causing harm to the immune system
Toxic Chemicals
How can splenectomy/hyposplenism affect the immune system?
Risk of sepsis with encapsulated organisms (lose macrophage in marginal zone)
How does pregnancy impact the immune system?
- Higher incidence of infection dependent upon cellular immunity
- Depressed cellular immunity during pregnancy
How does stress impact the immune system?
- Diminished cellular immune function
- Reduced NK activity, depressed lymphocyte mitogen responses
What is the major cause of acquired immunodeficiency in the world?
HIV
What are examples of non-HIV infections that result in immunodeficiency?
- Measles
- Herpesvirus
- Parasites
What is the impact of measles on the immune system?
- Significant immune suppression –> superinfection
- T cell lymphopenia
- Diminished T cell proliferation
- Diminished antibody production
- Infection of T cells and dendritic cells by measles
How can herpesvirus affect the immune system?
Can cause transient depression of cell-mediated immunity (esp with cytomegalovirus (CMV))
How can parasites affect the immune system?
- Decreased cell-mediated immunity in malaria
Bacteria producing toxins
Superantigens
How can superantigens affect the immune system?
- Sig immune stimulation, but T cells eventually decrease
2. Neutrophil function is decreased
