Immunology L4: Acquired immunodef

Question 1

Secondary or Acquired Immunodeficiency

Answer 1

• Iatrogenic
• Malignancy
• Malnutrition
• Renal disease
• Sarcoidosis
• AIDS

Question 2

Immune Effects of Vitamin A deficiency

Answer 2

Maintains integrity of respiratory and intestinal epithelium

• Deficiency inhibits Th1 and Th17 cells & increases mortality from:

– Diarrhea
– Plasmodium falciparum malaria

– Measles

Question 3

Immune Effects of Vitamin D Deficiency

Answer 3

• Decreased Macrophage function
• Results in increased incidence of:

– Tuberculosis
– Respiratory infections
– Otitis media

– Auto-immunity

Question 4

Immune defects of elemental deficiency

Answer 4

Zinc

– Required for thymic function

– Supplementation ↓ incidence and mortality from pneumonia, diarrhea, and malaria.

Iron
– Impt for neutrophil & T cell function
– Also necessary for pathogen replication

Question 5

Acute Retroviral Syndrome

Answer 5

• Occurs in 40 – 90%
  
  • – Begins 3-6 wks after infection – Lasts for 2 – 4 wks
• Sore throat, myalgias, fever, weight loss, fatigue, lymphadenopathy, rash, diarrhea, vomiting
• Subsequent viremia (HIV-1 RNA levels in blood) is a useful prognostic marker of disease progression.

Question 6

Chronic HIV Infection Phase

Answer 6

• Often called clinical latency
• HIV is continuously replicating in LN and spleen, but few clinical manifestations are present.
  
  • – Oral or vaginal candidiasis
  • – Herpes zoster
  • – Tuberculosis

Question 7

Effects of HIV on T Cells

Answer 7

Reduced Ag-induced proliferation

– Defects in intracellular signaling

– Loss of Th1 relative to Th2 responses: ↑ susceptibility to viruses & intracellular microbes
– Loss of memory T cell responses

Mechanisms of T Cell Loss

• Direct cytopathic effect
• inflammatory cell death (pyroptosis): IFI16 sensor and pyroptosis, a form of inflammatory cell death that requires caspase-1 activated by inflammasomes.
• Destruction of thymus architecture leads to decreased T cell production

Question 8

Effects of HIV on Non-T Cells

Answer 8

• Impaired microbiocidal activity
• Decreased chemotaxis
• Decreased IL-1; inapprop. TNF
• Poor Ag presentation
• Polyclonal B cell activation
• Impaired response to new or polysaccharide Ags

Question 9

Long-Lasting HIV Protection

Answer 9

Insoluble analog of dolutegravir,