Severe combined immunodeficiency
From IDWiki
Background
Epidemiology
- Most common form of severe primary immunodeficiency
Pathophysiology
- No or almost no T-cells, and any that exist do not work properly
- Many genetic abnormalities can lead to this condition, and may cause related defects in B and NK cell lines
- However, given that T-cells are required for B-cell function, all SCID patients are functionally B-cell deficient
Definition
- T-cell count <300 cells/μL and no T-cell response to mitogens (<10% compared to controls)
- Hypomorphic SCID is less severe, with a normal number of T-cells, but with T-cell function <30% compare to controls
Clinical Presentation
Diagnosis
- Usually diagnosed at birth with newborn screen containing a TREC (T-cell receptor excision circles) assay
Prognosis
- Uniformly fatal in childhood unless treated
