Primary Immunodeficiencies Flashcards
Primary immunodeficiencies are a group of >300 rare chronic disorders. Single gene defects. Give 5 types of primary immunodeficiencies
What are the 2 most common forms
Can be classified into 3 groups
*Antibody disorders
*T-cell disorders
Phagocyte disorders
Complement deficiencies
Auto-inflammatory syndromes
Neutrophil defects
Antibody deficiencies
Cellular immunodeficiency
Innate immune disorders
What would make you think of a PID? [6]
If the patient (usually a kid) gets infections that are abnormally:
- Severe (needs hospital or IV abx)
- Persistent
- Unusual organism
- Recurrent
- Runs in the family
Management of PID - 3 modalities, name 4 therapies that target the cause
Symptomatic treatment and prophylactic measures
Genetic Counselling & prenatal diagnosis
Target the cause where possible:
- Immunoglobulin Substitution for B cell disorders
- Gene Therapy (e.g. for SCID genes)
- Stem Cell Transplant e.g. CGD
- Thymus Transplant for DiGeorge
What infections are likely in a phagocyte disorder? [2]
Staph Aureus manifesting in sepsis, skin lesions, visceral abscesses
Aspergillus in the lung, bone or brain
In neutrophil defects, if the following have a mutation, how can this manifest in the patient? Absence of neutrophils Adhesion Recognition and phagocytosis Intracellular killing
§ Absence of neutrophils leads to congenital neutropenia
§ Adhesion > leukocyte adhesion defect
§ Recognition and phagocytosis > deficiencies of Pathogen Recognition Receptor
§ Intracellular killing > chronic granulomatous disease
□ 5 proteins make up NADPH-oxidase complex
Cannot produce H202 (potent -cidal agent)
What conditions occur in Complement deficiencies? [3]
Neisseria Meningitidis
Hereditary Angioedema
What is hereditary Angioedema? [3]
A c1-inhibitor deficiency of autosomal dominant inheritance –> Inflammation & oedema
How does Hereditary Angioedema present? [2]
Recurrent painless, non-pitting, non-pruritic, non-erythematous swelling [1] in subcutaneous tissues, intestines & Oropharynx [1]
How do you treat Hereditary Angioedema? [2]
What intuitive drug will prove ineffective in HA?
Emergency management of the airway obstruction or abdo pain
C1-inhibitor infusion OR fresh frozen plasma
Steroids, anti-histamines are ineffective
What are SCID genes? [1]
A set of genetic mutations [1] that cause fatal combined immunodeficiencies [1] in the innate immune system [1]
What kind of infections are you likely to get from a B cell deficiency? [3]
Recurrent resp bacterial infections e.g. Strep Pneumoniae & H influenzae
What infections can you get from a T cell disorder ie a cellular immunodeficiency [2]
Opportunistic Infections e.g. Pneumocystic Jirovecii or CMV
What’s the most common T cell “syndrome” deficiency?
Digeorge Syndrome aka 22q11 deletion
Cellular immunodeficiencies-
How does 22q11 present? [8]
Cardiac defects, Abnormal facies, Thymic hypoplasia, Cleft palate, and Hypocalcaemia
Learning and developmental disabilities, psychiatric and behavioral problems
What is thymus aplasia likely to cause in 22q11 deletion syndrome? [5] + [4]
- Reccurent RTIs in infancy
- Low T-cell numbers and qualitative defects
- Low IgA and IgM
- Reduced ab responses
- Autoimmune Phenomena:
- Anaemia/thrombocytopenia
- JIA
- Raynaud’s
- Thyroid disease
