Severe Combined Immune Deficiency / SCID (Pediatrics)
What is severe combined immune deficiency?
Severe combined immune deficiency (SCID) is the most severe form of primary immunodeficiency. Patients are born with the complete absence of T cells. Some patients also have B cell cytopenia (low B cells). These defects lead to extreme susceptibility to serious infections from the first months of life. Infants with this condition must be treated immediately with bone marrow transplantation, or, in select cases, with gene therapy to restore the immune system.
Before the institution of newborn screening for severe combined immunodeficiency, the incidence of this condition was estimated to be 1 in 100,000 live births. However, with the newborn screening started in many states, the true incidence is established as 1:40,000 -1:60,000 births.
What causes severe combined immune deficiency?
Many genetic defects may cause this condition. Examples are:
- Deficiency of the common gamma chain of the T cell receptor (X-SCID)
- Adenosine deaminase deficiency
- Deficiency of the alpha chain of the IL-7 receptor
- Deficiency of janus kinase 3
- Deficiencies of CD3 chains
- Deficiency of CD45
How is severe combined immune deficiency diagnosed?
Newborn screening detects this condition in the first weeks of life. The diagnosis is confirmed by measurement of lymphocyte counts, T, B, and NK cell counts, immunoglobulins, lymphocyte functional testing, and genetic testing.
What is the treatment for severe combined immune deficiency?
Early identification is essential. At ColumbiaDoctors Children's Heath, we have a New York State-approved Newborn SCID Specialized Center to aid in rapid diagnosis of this condition. Fortunately, there are effective treatments, such as stem cell transplantation, that can cure SCID and save lives.