Immunodeficiency Flashcards
What are the defects in recurrent/chronic pyogenic infections?
Antibodies B cells Complement Phagocytes Mostly caused by encapsulated bacteria
What are the defects of opportunistic infections or cancer?
T cell alone or combined
Mostly caused by viruses, fungi and parasites
Live viral vaccines are contraindicated (MMR,VAR,ZOSTERVAX,LAIV)
What is the most common primary immunodeficiency?
Selective IgA
Affected mostly caucasians
What is the treatment of primary B cell?
Control infections with antimicrobials
Immunoglobulin (IG) replacement therapy
Do not treat IgA deficiency with replacement IG
What are the B cell and antibody deficiencies that are X linked?
X linked (Bruton’s) agammaglobulinemia X linked Hyper-IgM syndrome
What are the B cell and antibody deficiencies that are autosomal?
Transient hypogammaglobulinemia of infancy
Selective IgA deficiency
Selective IgM or IgG subclass deficiencies
Common variable immunodeficiency
Autosomal Hyper-IgM syndrome
What is the presentation of X linked Agammaglobulinemia (XLA)?
Affects males only
Onset between 3 months and 3 years
Repeated pyogenic bacterial infections not responding to antibiotics
Bronchiectasis is a common cause of death
Caused by defect of BTK gene
How to diagnose XLA?
Near absence of all antibody classes
No ABO isohemagglutinins
Near absence CD19+ B cells in blood
BTK gene defect is confirmatory
What is the presentation of selective IgA deficiency?
Many remain asymptomatic
Symptomatic patients present with celiac disease, autoimmunity such as RA, SLE
May progress to CVID
May possess IgE directed toward IgA
How is selective IgA deficiency diagnosed?
Serum IgA<5-7 mg/dL
Normal IgG and IgM
How is selective IgA deficiency treated?
Antimicrobials
No IVIG or SCIG
What is the presentation of IgM and IgG2 deficiencies?
Can’t respond to polysaccharide capsules on bugs or in vaccines
Agressive use of antibiotics for treatment of recurrent respiratory tract infections
Replacement IG is controversial
What is the presentation of Transient Hypogammaglobulinemia of Infancy (THI)?
Period of hypogammaglobulinemia more severe and more prolonged beyond 6 months
Correct itself by age 3
B or TH presenting as antibody deficiency
How is THI diagnosed?
Serum IgG low>2SD below norm
IgM or IgA normal or low
How is THI treated?
Antimicrobials as needed
Delay live vaccines shot
IG not usually given
What is the presentation of Common Variable Immunodeficiency (CVID)?
Affect both sexes
Usually after age 4, typically in 30s
May follow EBV infection
May follow selective IgA deficiency
Increase incidence of giardia
Mothers cannot confer passive protection on infants
Caused by B cells not developing into plasma cells—-> low serum antibodies
How is CVID diagnosed?
Low CD27+
Normal CD19+CD20+
Treated with antimicrobials, IG replacement
What are the characteristics of Hyper-IgM syndrome?
Patients present with recurrent respiratory infections beginning at 1-2 years
Inability to switch from production of IgM to other isotypes
X linked is 70% of the cases
Diagnosed by reduced IgG, IgA, elevated or normal IgE
How is Hyper-IgM treated?
Antibiotics
Replacement IG
Stem cell transplant
What are the X linked T cell deficiency?
X linked SCID
Wiskott-Aldrich syndrome (WAS)
What are the autosomal T cell deficiencies?
Autosomal SCID Omenn syndrome Bare lymphocyte syndrome Ataxia telangiectasia Hyper IgE syndrome DiGeorge syndrome Chronic mucocutaneous candidiasis
What are the characteristics of SCID?
Heterogenous disorder with defects in both CMI and antibody production
Fatal by age 1 if not treated
Patients are susceptible to all types of infection: CMV,C.albicans
Vaccination with live microbes is lethal
Symptoms occur earlier than in XLA
What is the treatment of SCID?
Antimicrobials
Stem cell transplant