Lecture 19

Question 1

Innate immunity

Answer 1

• cellular: neutrophils, NK cells
• humoral: complement, antibodies
• cancer therapies and immunosuppressive drugs reduce function

Question 2

Adaptive immunity

Answer 2

• cellular: T cells
• humoral/spleen: B cells
• monoclonal antibodies targeting B cells impair antibody production
• no spleen/function heighten risk

Question 3

Mucosal barriers

Answer 3

• mucoliliary clearance in lungs
• acidic environment in stomach
• gut microbiota provides colonization resistance

Question 4

barrier injury

Answer 4

• skin disrupted by needles/catheter
• chemotherapy/cytotoxic treatment causes mucosal damage, facilitates bacterial infections
• malnutrition impairs neutrophils and T-cells

Question 5

Comorbidities

Answer 5

• psychological stress, diabetes, smoking
• treatment for malignancies can harm surrounding tissue

Question 6

Immunodeficiency disorders

Answer 6

one or more components of the adaptive or innate immune response is impaired
- inability to effectively resolve infections

Question 7

Primary immunodeficiency

Answer 7

inherited immune disorders resulting from genetic mutations
- usually present at birth, childhood
- single gene mutations or unknown genetic susceptibility

Question 8

Secondary immunodeficiency

Answer 8

• acquired from other condition: HIV, malnutrition, medical treatment
• managed by treating the primary condition

Question 9

Burden of disease

Answer 9

• 70-90% are undiagnosed
• SID more common than PID
• complications have significant cost-burden
• diagnosis before 3.5 months could reduce costs

Question 10

Age associations

Answer 10

• most people diagnosed as a child: most severe cases
• some diagnosed as adults: less serious but many infections

Question 11

Young children diagnosis

Answer 11

• recurrent infections within 1 year
• failure to thrive
• family history of PID

Question 12

B cell immunodeficiencies

Answer 12

• adaptive
• loss of antibody production
• risk of severe recurrent bacterial infections

Question 13

T cell immunodeficiencies

Answer 13

• adaptive and both
• combined immunodeficiencies (defective T and B cell function)

Question 14

Severe combined immune deficiencies (SCID)

Answer 14

• immune and adaptive
• lack T cells and reduced B cells
• usually diagnosed in the first year

Question 15

Phagocyte (WBC)

Answer 15

• innate
• phagocytes can’t destroy pathogens
• infections cause severe disease

Question 16

Complement defects

Answer 16

• innate
• lack complement proteins
• highly susceptible to meningitidis

Question 17

Asplenia

Answer 17

• lack of spleen function
• innate, adaptive, and both

Question 18

Prevention

Answer 18

• bone marrow transplant before 3 months
• screen for disorders at birth

Question 19

Treatment

Answer 19

supportive therapy:
- preventative antibiotics and antifungals
- antibody replacement therapy
key vaccines recommended but live vaccines avoided
- herd immunity

Question 20

SID causes

Answer 20

• protein calorie malnutrition
• immunosuppressive drugs for transplants
• chronic infections: HIV/AIDS

Question 21

Asplenia types

Answer 21

• congenital asplenia
• surgical splenectomy: trauma, immune disorders
• sickle cell dz: progressive asplenic infarction

Question 22

post-splenectomy infection bacteria

Answer 22

• encapsulated bacteria: s pneumoniae, h influenzae type B (Hib), n meningitidis
• unusual gram negatives: capnocytophaga canimorsus (dog bites/scratches)

Question 23

post-splenectomy infection protozoa

Answer 23

• babesia microti (ticks, blood transfusion)
• plasmodium falciparum
• severe parasitemia and complications

Question 24

Prevention for post-splenectomy infections

Answer 24

• daily antibiotic prophylaxis

Question 25

Infections in cancer

Answer 25

- rates of infection vary based on type/intensity of chemotherapy, disease status - highest rates occur in acute myeloid leukemia during high intensity treatment phase

Question 26

Cancer treatment impacts

Answer 26

- mucositis and microbiota alterations contribute to increased risk - chemo/radiation reduce beneficial bacteria - central venous catheters increase risk - surgical site infections

Question 27

Neutropenic fever

Answer 27

development of fever when low neutrophils - deeper and longer the neutropenia, higher risk of fever - risk increases after 7 days - mortality rates up to 70%

Question 28

Neutropenic fever causes

Answer 28

- microbiologically defined infection - clinically defined infection - fever of unclear origin

Question 29

neutropenic pathogens

Answer 29

80% of microorganisms arose from endogenous microbial flora - caused by all types of pathogens, many causes - gram negative dominant (p aeruginosa) in 60s-70s, gram positive (staph, s aureus) dominant after 80s

Question 30

Cancer patient infection prevention

Answer 30

- prophylaxis recommended for all - influenza vaccine - little impact but no real alternative