Immune deficiency Flashcards
Immunodeficiency
Immune system ability to fight infection and cancer is compromised or entirely absent due to defects in one or more immune components
Primary immunodeficiency
Immunodeficiency as a result of genetic defects (mutations, polymorphisms, polygenic)
Secondary immunodeficiency
Immunodeficiency due to environmental factors
- Malnutrition
- Malignancy
- Infection
- Diabetes
- Splenectomy
Mutations
Permanent alteration in DNA sequence (non-functional)
Polymorphisms
Alterations which involve 1 or more alleles (can be functional) - e.g. HLA
Polygenic disorders
Caused by combined action of >1 gene, normally affects antibody production
Primary immunodeficiency presentation
SPUR infection
- Sudden
- Persistent
- Unusual
- Recurrent
RAG or TAP mutation
Infection with all pathogens
B-cell defect
Infection with encapsulated bacteria
- Haemophilus
- Pneumococcus
Phagocyte defect
Infection with
- Staph
- Gram -ve bacteria
- Fungi
Complement defect
Infection with Neisseria
T-cell defects
Infection with intracellular pathogens
- Protozoa
- Viruses (herpes)
- Bacteria (myco)
Tumours
- Kaposi sarcoma
- Non-Hodgkin lymphoma
Primary immunodeficiency investigation
- Clinical presentation
- FH
- Lymphocyte count
- Antibody levels
Primary immunodeficiency treatment
Prevent infection
- Avoid live vaccines
- Avoid blood transfusion
- Genetic counselling
- Prenatal diagnosis
- Prophylactic antibiotics
Immunoglobulin replacement therapy
Transplantation
Thymic hormones
Gene therapy
Severe combined immunodeficiency (SCID)
Group of disorders that affect both T and B-cells
- RAG mutations
- Infection with all pathogens
- FH of early death
- Screen
- SCT is curative (early!)
