14) Immunodeficiency Flashcards
primary vs secondary immune deficiency syndromes
primary – deficiency is cause of disease
secondary – deficiency is a sx of disease
primary immunodeficiencies are categorized based on…
the expressed defect
SCID
severe combined immunodeficiency diseases
T and B cell defect
SCID patient suscpetible to…
any infection, especially…
- CMV
- Pneumocystis jiroveci
- Candida
T- B+
(2 types)
X-linked SCID: T cells ↓ and B cells don’t function (lack of T cell ILs)
autosomal recessive SCID: same clinically; JAK3 mutation
T- B-
(2 types)
adenosine deaminase deficiency: T/B cells don’t develop; skeletal abnormalities; toxic waste buildup
recombinase deficiency: Rag genes cannot rearrange; maturation stops at pre-T/B
Omenn syndrome
recombinase deficiency (SCID) with partial Rag activity
acts like graft-vs-host disease
infiltrates of T-cells, eos, and hyper-IgE in GI/skin
T+ B+
(3 types)
SCID with normal T/B numbers and abnormal function
- bare lymphocyte syndrome
- Wiskott-Aldrich syndrome
- Ataxia telangiectasia
MHC is lacking; T-helpers do not get presented with Ag
bare lymphocyte syndrome
reversed CD4:CD8 ratio (more CD8)
thymic epithelials cannot select CD4+ cells
bare lymphocyte syndrome
triad of Wiskott-Aldrich syndrome
- thrombocytopenia with small plts
- recurrent bacterial infections
- allergic rxn, hyper-IgE, food allergies, eczema
patients unable to respond to polysaccharide Ag
Wiskott-Aldrich syndrome
lifespan of 3 years without tx
cure is BM transplant
Wiskott-Aldrich syndrome
staggering gait + spiderlike vascular dilation
Ataxia telangiectasia
lymphopenia, thymic hypoplasia
↓ IgA, IgE, IgG
increased susceptiblity to malignancies
Ataxia telangiectasia
in T-cell immunodeficiencies, Ab may be lacking because…
lack of functional T-helpers
patients with T-cell immunodeficiencies susceptible to…
viruses
bacteria
fungi
protozoa
thymus and parathyroid do not form
↓Ca and lack of T-cells
no IgG (no class switching)
congenital thymic aplasia
(DiGeorge syndrome)
cardiac disease
chronic infections
congenital thymic aplasia
(DiGeorge syndrome)
selective defect in T-cells
no cell-mediated response to C. albicans
chronic mucocutaneous candidiasis
pre-B cells do not mature, so no Ig
severe, repeated bacterial infections when mom’s Ab is gone (5-6 months)
Bruton’s agammaglobulinemia (x-linked infantile agammaglobulinemia)
repeated infections with…
H. influenzae
S. pneumoniae
Bruton’s agammaglobulinemia (x-linked infantile agammaglobulinemia)
Bruton’s agammaglobulinemia tx
IV IgG
cannot make IgG from 2 months to 2 years
↓ T-cell number and function
transient hypogammaglobulinemia
