Hogan: Primary Immunodeficiencies Flashcards
What makes up about 1/2 of all primary immunodeficiencies?
antibody defects
Besides antibody defects, what is the next most commong cause of primary immunodeficiency disease?
- antibody defects
- combined immuno-deficiencies
- phagocytic defects
- T-cell defects
- complement defects
Is there complete phagocyte function in a neonate? What about complement function?
yes, leukocytes have passed from the liver and spleen to the bone marrow before birth and phagocyte functionality is complete; complement function is available in a neonate due to maternal passage of IgG, however, antibody mediated complement fixation lags until Ab production is initiated in a neonate (~6mo)
Is NK cell function available in neonates?
yes
Is T cell function complete at birth?
yes, via thymic development
Is B cell function complete at birth?
no, B cells must wait for T cells to mature before they can mature and have functional antibody function; T cells are functional at birth, but B cells are not functional until about 6-24 months.
What happens to B cells if T cells fail to develop?
B cell functionality will suffer
For approximately how many months of a neonate’s life is he/she protected by maternal antibodies?
6 months; after this, the 1/2 life is about over and the child can begin to develop his/her own antibodies.
What comes first - immunodeficiency or autoimmunity?
Either/or!
What do autoimmune problems in a patient suggest difficulty in?
B cell maturation
isotype switching
tolerance
Phagocytes are (blank): Both Gram+ and Gram- and yeast/fungal organisms are attacked
non-discriminatory
What are these types of organisms typically associated with:
Staphylococci aureus Pseudomonas aeroginosa Aspergillus fumigatus (fungal) Candida (yeast) Enterbacteriaceae Others: Nocardia (Gram + rod) /Listeria (Gram + rod)
neutrophil disorders
Failure of the attack complex in complement disorders result in susceptibility to (blank)
Neisseria
Absence of (blank), which is at the heart of the complement cascade, makes the response to severe bacterial infections difficult
C3
Otitis media, draining ears, sinusitis, pulmonary infections are common in what type of deficiency?
B cell (humoral) deficiency
Why are recurrent ear infections (otitis media) abnormal after children reach middle school age?
eustachian tube anatomy improves with facial growth to allow for “downhill” drainage
What are these organism likely associated with?
Pnuemocystis carinii
Candida: invasive (lung/esophagus)
Systemic viral illness (CMV etc.)
Mycobacterial infections
T cell problems
What are some clinical characteristics of T cell deficiencies?
family history onset BEFORE 6mo failure to thrive no lymph nodes cutaneous lesions severe fungal/viral infection diarrhea
What are some clinical characteristics of B cell deficiencies?
family history of autoimmune/immunodeficiency recurrent virulent bacterial infections allergy/autoimmune disease vaccine failure sinopulmonary infections FTT
What are some clinical characteristics of phagocytic deficiencies?
susceptible to low grade bacteria and fungus severe infections skin infections lymphadenitis abscesses delayed umbilical cord separation
If you have a C3 complement deficiency, how might you present?
with recurrent bacterial infections
If you have deficiencies in C5-C8 complement proteins, what might you present with?
Neisseria infections
What is the best lab test to order if you suspect an immunodeficiency?
CBC with differential
If you have azurophilic granules, what do you think of?
Chediak Higashi
If you have increased neutrophils, what do you think of?
infection
leukocyte adhesion deficiency (cannot diapedis)
If you have decreased neutrophils, what do you think of?
congenital absence
autoantibody
cyclic neutropenia
With RBC abnormalities, what do you consider?
autoimmune anemia
g6pd deficiency
If low lymphocytes (lymphopenia), what do you consider?
SCID
If you have small platelets or a decreased number, what do you think of?
Wiskott-Aldrich syndrome
If you have ZERO CH50, what is wrong?
a genetic defect in the complement cascade **order individual complement components to sort it out
profound sepsis
If you have ZERO AH50, what is wrong?
genetic deficiency in the complement cascade
If AH50 and CH50 are BOTH zero, which complement proteins might be impaired?
C3, C5-C9
**test specific complement components in this case
When measuring IgA, what should you keep in mind?
any value greater than zero is OK despite what reference values predict
Why is albumin testing relevant to B cell lab work?
it allows you to determine if IgG loss is secondary
If you have a child with nasal polyps, what should you think of?
cystic fibrosis
The following vaccines have what component?
diphtheria
tetanus
H flu
protein component
What is an isohemagluttinin?
IgM molecule that helps identify which ABO blood group a person belongs to
How long will it take to make IgG after a booster shot?
1 month
What are CD3, CD4, and CD8 markers for?
T cells
What is CD19 a marker for?
B cells
What are some suspected T cell disorders?
HIV
deficient in CD3, CD4, CD8, 19 or 56
When is it appropriate to do specific antigen studies?
if a patient is >1yo and/or has been vaccinated
What can be used to stimulate lymphocytes?
mitogens
In a neonatal chest X ray, what should you look for?
“sail sign” - the thymus
What test can be used to determine neutrophil functionality?
flow cytometry
What are some red flags for immunodeficiency in regards to pneumonia?
> 2 cases of pneumonia
pneumonia that requires hospitalization
