FMS Week 10: Primary Immunodeficiency Flashcards
Main Characteristics of Primary Immunodeficiency Disease
3 Listed
- Primary (congenital)
- Group of highly variable diseases
- Almost always a genetic defect
Primary Immunodeficiency Disease Primary (Congenital)
- Mutation/defect is present at birth perinatally
- Not caused by damage to the immune system (secondary)
Primary Immunodeficiency
Mutation/defect is present at birth
Secondary immunodeficiency
Not caused by damage to the Immune system
Primary Immunodeficiency highly variable disease
2 Listed
- time of manifestation ranges from birth to never
- Severity ranges from mild/no known symptoms to fatal
Primary Immunodeficiency Disease is almost always a genetic defect because?

How many Primary Immunodeficiency Diseases are there?
>200 distinct Primary Immunodeficiency Diseases
Diagnosis of Primary Immunodeficiency Diseases
2 Listed
- recurrent or severe infections are usually the first sign of a possible primary immunodeficiency disease
- Infections at multiple sites, multiple pathogens (including normally avirulent)
Primary Immunodeficiency Diseases are associated with unexpected pathology such as
3 Listed
- Autoimmune diseases
- Cancer
- Allergy
Primary Immunodeficiency Diseases: Defects of innate immunity
4 Listed

Primary Immunodeficiency Diseases: Defects of lymphocyte Maturation
5 Listed

Primary Immunodeficiency Diseases: Defects of lymphocyte Activation
4 Listed

Primary Immunodeficiency Diseases: Other genetic disease with lymphocyte abnormalities

Inheritance of Primary Immunodeficiency Diseases
2 Distinct Patterns
- Autosomal Recessive Inheritance (requires 2 defective genes)
- X-linked Recessive
Primary Immunodeficiency Diseases: Autosomal Recessive Inheritance Pattern
2 Listed

Primary Immunodeficiency Diseases: X-Linked Recessive Inheritance Pattern
4 Listed
Defects in Lymphocyte Maturation Disease Examples
5 Listed

Combines Immunodeficiency Syndromes occur in 1/? live births
1/58,000 live births
Mutations in genes whose products are crucial for the development and function of B and T cells may also affect…
NK cells
Disorders arising from disturbances in the development of B and T cells may also involve?
Natural Killer (NK) Cells
Primary Immunodeficiency Diseases can be “Severe” in that they
They lead to death from overwhelming infection, usually in the first year of life
Since 2010 90% of newborns in the U.S> are screened for?
SCID
SCID Patient Presentations
5 Listed
- Severe infections
- Lymphopenia
- Chronic Diarrhea
- Adverse reactions to live vaccines
- recurrent fevers
Treatment of Combined Immunodeficiency Syndromes
Hematopoietic cell transplantation (HCT)
Combined Immunodeficiency Syndromes Prognosis
Fatal in the first year of life if not treated, best prognosis is in patients receiving HCT before 3.5 months of age with no infections
T Cell Receptor Excision Circles are?

TRECs Properties
4 Listed

Patients with SCID will not have mature T cells so they will not have _________
TRECs in the blood
X-Linked Severe Combined Immunodeficiency Disease: what type of mutation is most common?
99% of X-linked SCID are caused by γc Mutations
X-linked SCID prognosis
Fatal in the first year or 2 of life if not treated
X-linked SCID are symptomatic/asymptomatic at birth
Asymptomatic at birth and time of testing
X-linked SCID: undiagnosed patients present in the first year with?
5 Listed
- Recurrent opportunistic infections
- Chronic diarrhea
- Thrush
- Otitis media
- Failure to thrive
γc deficiency =
X-linked Severe Combined Immunodeficiency
γc is shared among many?
Cytokine receptors
- IL-2
- IL-4
- IL-7
- IL-9
- IL-15
- IL-21
IL-7 is required for?
T cell development and differentiation
IL-7 is produced in the ________ and signals through the _________ receptor to induce _______________
- Thymus
- IL7R/γc
- proliferation of pro-T cells
With γc deficiency, the effect on B cells is?
- B cell number will be normal but serum Ig will be low because there are no CD4+ T cells to stimulate B cells
Autosomal Severe Combined Immunodeficiency: mutations in nucleotide salvage pathway Percentages
- ~30% of autosomal SCID are caused by mutations in the gene coding for adenosine deaminase (ADA) enzyme
- 1% of all SCID is caused by a mutation in Purine Nucleotide Phosphorylase (PNP) enzyme
ADA and PNP are both involved in?
Converting toxic deoxyadenosine (a byproduct of breakdown and synthesis of DNA) to non-toxic byproducts that can be salvaged for DNA synthesis or removed as waste products
Deficiency in ADA or PNP causes?
Build up of toxic deoxyadenosine
Treatment for ADA or PNP SCID
2 Listed
- Hematopoietic Cell Transplant
- Enzyme replacement therapy (weekly intramuscular injection)
ADA AKA
Adenosine Deaminase Enzyme (ADA)
PNP AKA
Purine Nucleotide Phosphorylase (PNP)
ADA and PNP deficiency toxic buildup of deoxyadenosine causes
2 Listed
- Decreased DNA synthesis
- Decreased Lymphocytes
RAG1 and RAG2 are?
proteins that are involved in VDJ recombination
Without RAG1 and RAG2 functionality
3 Listed
- There will be no B or T cells because the cells would not be able to make it past checkpoints early in development
- Pro-Pre checkpoint
- Pro B & T cells need to undergo VDJ recombination which involves RAG1 and RAG2 proteins

For Survival Pre-B cells require:
4 Listed
- Successfully rearranged H chain
- Association with surrogate light chains
- Association with Ig-signaling molecules
- Basal signaling
Btk Deficiency: X-linked agammaglobulinemia
can’t get mature B cells

DiGeorge Syndrome caused by
2 Listed
- deletion in chromosome 22q11.2
- resulting in abnormal embryonic development of the pharyngeal pouch system
Functional Defect in DiGeorge Syndrome
Rudimentary or absent thymus
The consequence of DiGeorge Syndrome
2 Listed
- Decreased T cells
- Normal B cells but normal or reduced serum Ig (SCID)
Clinical Aspects of DiGeorge
5 Listed
- Rudimentary or absent thymus
- Cardiac Anomalies
- Hypocalcemia (from parathyroid hypoplasia)
- Palatal defects
- Gastrointestinal defects
Treatment of DiGeorge Syndrome
- Hematopoietic Cell Transplant (does not fully restore T cell repertoire but does provide adequate immune function)
Prognosis of DiGeorge Syndrome
Median survival with transplant is 5 years (oldest survivors are in their 20s)
Examples of defects of lymphocyte activation
5 Listed
- Defects in TCR complex signaling: MHC Class II deficiency
- Common Variable Immunodeficiency
- AID mutations (autosomal hyper-IgM syndrome)
- CD40 Ligand mutations (X-linked hyper-IgM syndrome)
- Selective Ig isotype defects

Common Variable Immunodeficiency is not a?
Not a single disease
Common Variable Immunodeficiency Prevalance
1/25,000
Common Variable Immunodeficiency is a Collection of?
Collection of hypogammaglobulinemia syndromes
hypogammaglobulinemia syndromes are resulting from
many genetic defects
Common Variable Immunodeficiency: Variable because?
5 Listed
Variable - heterogeneous clinical manifestations
- Recurrent Infections
- Chronic Lung Disease
- Autoimmune Disorders
- Gastrointestinal Disease
- Susceptibility to lymphomas
Common Variable Immunodeficiency Age of diagnosis
2 Listed
- sometimes diagnosed in childhood, but more often after puberty (20-45 years is the most common age)
- Often diagnosis is delayed (5-7 years after symptoms present)
Common Variable Immunodeficiency: Specific Gene Defect
2 Listed
- the specific molecular defect is known only for a small subset of patients
- likely results from a number of different gene defects
Common Variable Immunodeficiency: Consequence
impaired B cell differentiation with hypogammaglobulinemia
Common Variable Immunodeficiency: Treatment
IVIG to replace low serum Ig
Hyper IgM Syndromes prevalence
Rare: 1 / 1,000,000
Hyper IgM Syndromes different mutations Examples
3 Listed
- Activation-induced deaminase (AID)
- CD40L
- CD40
AID Inheritance Pattern
Autosomal Recessive
CD40L Inheritance Pattern
X-Linked Recessive
CD40 Inheritance Pattern
Autosomal Recessive
Hyper IgM Syndromes Functional Defect
2 Listed
- Failure of IgM class switching and somatic mutation
- Lack of memory B cells
Hyper IgM Syndromes: Consequence
4 Listed
- Recurrent pyogenic infections
- neutropenia
- elevate IgM with absent IgG, IgA, IgE
- decreased B cells
Hyper IgM Syndromes Treatment
3 Listed
- CD40 and CD40L defects are more difficult to treat (T cell defects require HCT)
- AID defects treated with IVIG
- Antibiotic prophylaxis
Hyper IgM Syndrome 2 AKA
HIM2
HIM2 AKA
Hyper IgM Syndrome 2
Hyper IgM Syndrome 2 Inheritance pattern
Autosomal Recessive
HIM2 mutation
Mutation in Activation Induced Deaminase (AID)
HIM2 Mutation Consequence
Failure of IgM class switching and somatic mutation
HIM2 Treatment
Because the defect is only B cells IVIG replacement and antibiotic prophylaxis is required
HIM1 Inheritance Pattern
X-linked Recessive
HIM13 Inheritance Pattern
Autosomal Recessive
HIM1 Mutation
CD40L
HIM3 Mutation
CD40
Pathology of HIM1 & HIM3
5 Listed
- Weak B/T cell interactions
- defective somatic mutation
- Defective class switching
- Defective T cell/macrophage interactions
- Lack of cell-mediated immunity
Chronic Granulomatous Disease caused by?
Mutations in phagocyte NADPH oxidase (a component of the phagocyte oxidase)
Chronic Granulomatous Disease Inheritance Pattern
X-Linked Recessive
Chronic Granulomatous Disease functional defect and Consequence
2 Listed
- inability of phagocytes to destroy certain microbes (primarily fungal and bacterial pathogens)
- Leads to chronic T cell stimulation of macrophages and granuloma infection
Chronic Granulomatous Disease Treatment
3 Listed
- Lifelong antibacterial and antifungal prophylaxis
- early diagnosis of infection
- aggressive management of infection complications
Chronic Granulomatous Disease Prognosis
average patient survives to 40 years old
Chediak-Higashi Syndrome Caused by?
Mutations in CHS1/LYST protein (a protein involved in regulating and trafficking of lysosomes in the cell)
CHS1/LYST protein function and disease involvement
2 Listed
- a protein involved in regulating and trafficking of lysosomes in the cell
- Involved in Chediak-Higashi Syndrome
Chediak-Higashi Syndrome Functional Defect and Consequence
2 Listed
- Defective lysosomal function in neutrophils, macrophages and dendritic cells, and defective granule function in natural killer cells
- Causes Recurrent bacterial infections
Other clinical aspects of Chediak-Higashi Syndrome
3 Listed
- oculocutaneous albinism
- coagulation defects
- progressive neurological deterioration
Chediak-Higashi Syndrome Treatment
2 listed
- Hematopoietic stem cell transplant (this does not alter neurological aspects of disease)
- Prophylactic antibiotics
Chediak-Higashi Syndrome Prognosis
2 Listed
- Without the transplant, death from bacterial infections before 7 years of age
- Severe and debilitating neurological deficits by 20 years of age
LAD AKA
Leukocyte Adhesion Deficiencies
Leukocyte Adhesion Deficiencies AKA
LAD
Leukocyte Adhesion Deficiencies Inheritance Pattern
Autosomal Recessive
Leukocyte Adhesion Deficiencies Causes
failure of neutrophil recruitment to the site of infection
LAD-1 Pathology
2 Listed
- Failure of neutrophil recruitment to site of infection
- also deficient T cell/APC interactions
LAD-1 Deficiency
- ß2 integrins (CD18, LFA-1, Mac-1) deficiency
LAD-2 Deficiency
E and P-selectin ligands (CD62) deficiency
LAD-3 Deficiency
Kindlin-3 deficiency results in decreased integrin activation
Complement Deficiencies predispose patients to…
2 Listed
- to bacterial infections (especially Neisseria species)
And/Or
- Systemic Lupus Erythematosus
Complement Deficiencies: Patients lose the activity of…
The defective protein but also the functions of the proteins that follow the particular cascade
Complement Deficiencies Deficiencies can be in?
Specific complement components or in the complement regulatory proteins
Complement Deficiencies Inheritance Pattern
Most are Autosomal Recessive
Complement Deficiencies: Homozygous deficiency
most will have complete deficiency of the complement component
Complement Deficiencies: Heterozygous deficiency
- Are generally asymptomatic
- 50% normal complement activity
Complement Deficiencies Treatment
2 listed
- vigilance for early signs of serious infection, vaccination
- possible antibiotic prophylaxis
Wiskott-Aldrich Syndrome Caused by?
mutations in X-chromosome protein Wiskott-Aldrich Syndrome Protein (WASp) protein expressed exclusively in hematopoietic cells and is involved in actin cytoskeleton remodeling
Wiskott-Aldrich Syndrome Functional defect and Consequence
3 Listed
- defective signaling from the cell membrane to the cytoskeleton
- impaired cell signaling in T and B cells
- Defective polarization, motility, and phagocytosis in neutrophils in neutrophils and macrophages
Wiskott-Aldrich Syndrome Other Clinical Aspects
7 Listed
- Variable presentation based on specific mutation
- Thrombocytopenia
- bleeding (petechiae or prolonged bleeding from umbilical stump of circumcision)
- sever infections
- eczema or varying severity
- autoimmune manifestations
- malignancies (lymphoma and leukemia)
Wiskott-Aldrich Syndrome Treatment
4 Listed
- prophylactic antibodies
- platelet transfusions
- IVIG in patients with antibody deficiency
- Hematopoietic transplant
Wiskott-Aldrich Syndrome Prognosis
2 Listed
- bleeding is the main cause of death
- malignancies are often fatal
Relative occurrence of primary immunodeficiency Diseases

Key features that suggest primary immunodeficiency disease
3 Listed
- Recurrent infections
- Severe infections
- infections with normally avirulent pathogens





Common Variable Immunodeficiency

Leukocyte Adhesion Deficiency