PIDS Flashcards
What type of cell immunodeficiency is associated with pyogenic bacteria and recurrent bacterial infections?
B cells
What are you at an increased risk of having if you have a T cell deficiency?
Cancer: t cells critical for surveillance against oncogenic viruses
Viral Infections
Autoimmunity: deficiency in Treg
Infection with intracellular microbes
What does a deficient delayed-type hypersensitivity (DTH) indicate?
T cell immunodeficiency
What is DiGeorge Syndrome? What is its phenotype? Can you give viral vaccines?
Selective T-cell deficiency caused by congenital malformation resulting in defective development of the thymus (deletion in chromosome 22)
- frequent upper respiratory infections
- recurrent viral infections
- commonly decreased number of T cells
T -, B +, NK +
Can give if have CD8 greater than 300
What is the classic triad that indicates undeveloped thymus (aka DiGeorge)?
cardiac anomalies
hypocalcemia
hypoplastic thymus
What is x-linked agammaglobulinemia? What is its phenotype?
B cell immunodeficiency: No IgA IgM or IgG, caused by defect in rearrangment of heavy chain
- Happens during pre- B cell stage (differentiation defect)
- Exclusively an abnormality of humoral response
HSCT is curative and should be considered
Recurrent bacterial infections
Seen in MALES because x-linked (there is also an autosomal form that presents the same way just not only in males)
B –, T + , NK +
What is selective IgA deficiency? What is its phenotype?
B cell immunodeficiency
- IgA titers are undetectable or very low, IgG and IgM are
normal. - have mature B cells just not plasma cells to produce IgA (maturation/differentiation issue)
Autosomal but higher in males
IgM can compensate for deficiency so often asymptomatic
may have serum anti-IgA IgG which has been linked to the development of non-IgE mediated anaphylaxis in response to an intravenous immunoglobulin
No vaccination restriction
B +, T + , NK +
What is common variable immunodeficiency? What is its phenotype?
B cell immunodeficiency
- LOW IgG and IgA; sometimes low IgM
- associated with Hypogammaglobulenmia= delay in IgG production
- recurrent pyogenic sinus infections
- at risk of infections, autoimmune disease, and malignancies
Autosomal disorder
HCST curative
B –/+, T + , NK +
What is hyper-IgM syndrome? What is its phenotype?
Failure of the B cell heavy chain to undergo switch from the IgM isotype resulting in ELEVATED IgM no IgG or IgA
- predisposed to pyogenic infections= encapsulated opportunistic infections
- normal numbers of peripheral B cells, but LOW
numbers of CD27-positive memory B cells.
X-linked: mutation in CD40L 2/3 of cases
autosomal: Cd40 deficiency 1/3 of cases
B +, T + , NK + in transient form it’s B-/+, T+, NK+
What is ADA deficiency? What is its phenotype?
Low IgG, IgA, and IgM
Accumulation of toxic for lymphocytesmetabolic by-products deoxyadenosine
Severe opportunistic infections
Autosomal recessive
HSCT is a treatment option
Do NOT give live vaccine
T -, B -, NK -
What is X-linked SCID (Common g Chain Deficiency)? What is its phenotype?
Caused by mutation in common cytokine gamma receptor= T cell growth receptor
disruption in IL-2
Non functional B-cells because T-cells aren’t able to help
- have IgM but no IgG or IgA
failure to thrive, severe thrush, opportunistic infections, and chronic diarrhea.
HSCT is an option
Do NOT give live vaccine
T -, B +, NK -
What morphological feature is commonly seen in patients with B cell deficiencies when lymph node biopsy is performed?
Reduced follicles and germinal centers
What immunodeficiency is the most common PID with a 1 in 700 in white individuals?
Selective IgA deficiency
What intracellular microbe is someone with hyper-IgM syndrome susceptible to?
Pneumocystis jiroveci
What is the difference between x-linked and autosomal hyper-IgM sydrome?
X-linked= deficiency in CD40L on T cells Autosomal= mutation in CD40 on B cells
What is Wiskott-Aldrich Syndrome (WAS)? What is its phenotype?
Low IgM; normal Ig, elevated IgA and IgE
T cell lymphopenia
Decreased NK cell cytotoxicity
Symptoms thrombocytopenia, eczema,
cellular and humoral immunodeficiency, autoimmune disease, and malignancy BLEEDING
- recurrent sinopulmonary infections
X-linked recessive
T -, B +, NK -
What type of deficiency is associated with fungal infections?
T-cells
What mechanism is someone with x-linked BTK impaired in?
Antibody-mediated bacterial clearance because have a near or total absence of B cells and Igs
When is bone marrow transplant effective?
When there is defect specifically in lymphocytic lineage
Effective in all SCID
What causes hereditary angioedema?
Deficient levels of C1 inhibitor
What is chronic granulomatous disease?
Defects in various degradative enzymes (NADPH oxidase)
or other molecules of the oxidative burst= impaired ability to kill microbes/phagocytosed bacteria
Similar to G6PD deficiency (asymptimatic) and myleoperoxidase deficiency
What test is used to see ability of killing microbes?
Tetrazolium test, evaluates effectiveness of oxidase enzymes
What is the diagnostic feature of Chediak-Higashi Syndrome?
Giant lysosomes clustered near the nucleus caused by defect in vesicle fusion –> impaired phagocytosis because endosome cant fuse with lysosome (chemotaxis and degranulation issue)
granules do not contain cathepsin G and elastase for decay of intracellular pathogen
NO NK Activity
What is an indicator of LAD type 1= leukocyte adhesion deficiencey?
Lacking CD11/CD18 cell markers
Cause defective migration of phagocytes into infected tissues
Delayed detachment of umbilical cord
Increased Neutrophil count even without infection because can’t bind to intracellular adhesion molecules of endothelial cells –> recurrent infection and inability to form pus
