Understanding SCID and CID
Severe combined immune deficiency (SCID) and combined immune deficiency (CID) are immune deficiency disorders characterized by an increased susceptibility to recurring infections. SCID is characterized by an absence of T-cells and little or no B-cell function. CID is characterized by impaired T-cell and B-cell function, although T-cells and B-cells are not absent. SCID and CID are inherited disorders – children inherit the gene from their parents. CID is similar to SCID but is a less serious and aggressive form of primary immune deficiency.
Symptoms of SCID and CID
Symptoms of both severe combined immune deficiency (SCID) and combined immune deficiency (CID) include frequent and severe respiratory infections. Other symptoms, which occur in infants, include poor growth, rashes similar to eczema, recurrent thrush in the mouth, chronic diarrhea, though all these symptoms may not occur.
Diagnosing SCID and CID
All states in the U.S and Washington, DC, and Puerto Rico screen newborns for SCID as a part of routine newborn screening. Screening for SCID measures a component of DNA, the T-cell receptor excision circle (TREC). Screening at birth affords the opportunity to identify and treat SCID before the onset of symptoms. Most states also screen for CID at birth with a blood test that measures lymphocytes (a type of white blood cell) in the blood.
Treating SCID and CID
Treatment of SCID and CID include prophylactic antibiotics, antivirals, antifungals and immune globulin replacement therapy. Immune globulin is extracted from a large pool of human plasma and contains all the important antibodies present in the normal population. Immune globulin therapy can be administered into the blood stream intravenously (IVIG) or under the skin subcutaneously (SCIG). The most accepted treatment for both SCID and CID is bone marrow or stem cell transplant which is curative.
References:
- CID | UPMC Children’s Hospital of Pittsburgh
- SCID | UPMC Children’s Hospital of Pittsburgh
- Severe Combined Immunodeficiency (SCID) | Immune Deficiency Foundation
Last reviewed 12/18/2025
