immunocompromised host

Question 1

what is the immunocompromised state?

Answer 1

immune system is unable to respond appropriately and effectively to infectious microorganisms

Question 2

what are the characteristics of an infection in an immunocompromised host?

Answer 2

SPUR
S = severe
P = persistent
U = unusual
R = recurrent

Question 3

what are the basic prinicples of primary immunodifficiency disease?

Answer 3

• diagnosis is often late so there is permanent tissue/organ damage
• caused by intinsic gene defects

Question 4

what primary immunodeficiency diseases are caused by antibody defects?

Answer 4

• Brutons disease
• common variable immunodeficiency (most prevelant that requires treatment)
• selective IgA deficiency (most prevelant that does not require treatment)

Question 5

what primary immunodeficiency disease is caused by T (or B) cell defects?

Answer 5

T + B cell defects:
* severe combined immunodefiency (SCID)

T cell defect:
* Di george syndrome

Question 6

what primary immunodeficiency is caused by phagocytic defects?

Answer 6

chronic granulomatous disease

Question 7

how are patients with primary immunodeficiencys diagnosed?

Answer 7

age of symptom onset:
* onset < age 6 months = T cell or phagocyte defect
* onset > 6 months or <5 years of age = B cell, antibody or phagocyte defect
* onset >5 years or later in life = B cell/antibody complement or secondary immunodeficiency

Question 8

how are primary immunodeficiency treated?

Answer 8

Supportive treatment:
* Infection prevention (eg prophylactic antimicrobials)
* Treat infections promptly and aggressively (eg passive immunization)
* Nutritional support (Vitamins A-D)
* Use UV-irradiated, CMV negative blood products only
* Avoid live attenuated vaccines in patients with severe PIDs (SCID

Selective treatment:
* Immunoglobulin replacement therapy (IRT) - goal is for serum IgG >8g/L & used for CVID, Bruton’s disease, IgA deficiency, Hyper-IgM syndrome.
* Hematopoietic Stem Cell therapy (HSCT, 90% success) - for SCID Comorbidities
* Autoimmunity and malignancies
* Organ damages (lung function assessment)  Avoid non-essential exposure to radiation

Question 9

what is secondary immunodeficiency?

Answer 9

usually acquired due to:
* Decreased production of immune components due to malnutrition, infection (eg HIV), liver diseases or splenectomy.
* Increased loss of immune components due to protein-losing conditions (nephropathy, enteropathy) or burns.
* Increased susceptibility to infections due to chemotherapy, invasive devices