Skip to main content
U.S. Department of Health & Human Services
National Institutes of Health
NCATS

COVID-19 is an emerging, rapidly evolving situation.

Get the latest public health information from CDC: https://www.coronavirus.gov (link is external)
Get the latest research information from NIH: https://covid19.nih.gov (link is external)

National Center for Advancing and Translational Sciences National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences
1-888-205-2311
Menu Search
1-888-205-2311
Menu
  • Home
  • Diseases expand submenu for Diseases
    • Browse A-Z
    • Find Diseases By Category expand submenu for Find Diseases By Category
      • Autoimmune / Autoinflammatory diseases
      • Bacterial infections
      • Behavioral and mental disorders
      • Blood Diseases
      • Chromosome Disorders
      • Congenital and Genetic Diseases
      • Connective tissue diseases
      • Digestive Diseases
      • Ear, Nose, and Throat Diseases
      • Endocrine Diseases
      • Environmental Diseases
      • Eye diseases
      • Female Reproductive Diseases
      • Fungal infections
      • Heart Diseases
      • Hereditary Cancer Syndromes
      • Immune System Diseases
      • Kidney and Urinary Diseases
      • Lung Diseases
      • Male Reproductive Diseases
      • Metabolic disorders
      • Mouth Diseases
      • Musculoskeletal Diseases
      • Myelodysplastic Syndromes
      • Nervous System Diseases
      • Newborn Screening
      • Nutritional diseases
      • Parasitic diseases
      • Rare Cancers
      • RDCRN
      • Skin Diseases
      • Viral infections
    • List of FDA Orphan Drugs
    • GARD Information Navigator
    • FAQs About Rare Diseases
  • Guides expand submenu for Guides
    • Patients, Families and Friends expand submenu for Patients, Families and Friends
      • How to Find a Disease Specialist
      • Tips for the Undiagnosed
      • Support for Patients and Families
      • Tips for Finding Financial Aid
      • Help with Travel Costs
      • How to Get Involved in Research
      • FAQs About Chromosome Disorders
      • Medical and Science Glossaries
    • Healthcare Professionals expand submenu for Healthcare Professionals
      • Caring for Your Patient with a Rare Disease
      • ICD Coding for Rare Diseases
      • FindZebra Diagnosis Assist Tool
    • Researchers expand submenu for Researchers
      • Finding Funding Opportunities
    • Teachers and Students expand submenu for Teachers and Students
      • Teaching Resources
  • News expand submenu for News
    • In The Spotlight
    • News Archive
    • Connect with GARD
    • Media Requests
  • About GARD expand submenu for About GARD
    • Contact GARD
    • About GARD
    • Videos
    • Brochures and Publications
  • En Español expand submenu for En Español
    • Enfermedades
    • Contacte GARD
    • Guías de Información expand submenu for Guías de Información
      • Preguntas Más Frecuentes Sobre Enfermedades Raras
      • Como Encontrar un Especialista en su Enfermedad
      • Consejos Para una Condición no Diagnosticada
      • Consejos Para Pacientes y Familias
      • Consejos Para Obtener Ayuda Financiera Para Una Enfermedad
      • Participe en Estudios de Investigación
      • Preguntas Más Frecuentes Sobre los Trastornos Cromosómicos
    • Sobre GARD
  • Home
© Positive Exposure
banner showing people with disabilities and/or their relatives
  1. Home
  2. Diseases
  3. Severe combined immunodeficiency
print
  • Table of Contents expand submenu for Table of Contents
    • Summary
    • Symptoms
    • Inheritance
    • Diagnosis
    • Treatment
    • Research
    • Organizations
    • Living With
    • Learn More
    • News & Events
    • Related Diseases
    • GARD Answers
  • Browse A-Z
  • Find Diseases By Category expand submenu for Find Diseases By Category
    • Autoimmune / Autoinflammatory diseases
    • Bacterial infections
    • Behavioral and mental disorders
    • Blood Diseases
    • Chromosome Disorders
    • Congenital and Genetic Diseases
    • Connective tissue diseases
    • Digestive Diseases
    • Ear, Nose, and Throat Diseases
    • Endocrine Diseases
    • Environmental Diseases
    • Eye diseases
    • Female Reproductive Diseases
    • Fungal infections
    • Heart Diseases
    • Hereditary Cancer Syndromes
    • Immune System Diseases
    • Kidney and Urinary Diseases
    • Lung Diseases
    • Male Reproductive Diseases
    • Metabolic disorders
    • Mouth Diseases
    • Musculoskeletal Diseases
    • Myelodysplastic Syndromes
    • Nervous System Diseases
    • Newborn Screening
    • Nutritional diseases
    • Parasitic diseases
    • Rare Cancers
    • RDCRN
    • Skin Diseases
    • Viral infections
  • List of FDA Orphan Drugs
  • GARD Information Navigator
  • FAQs About Rare Diseases

Severe combined immunodeficiency


Back to List of Questions

Question Question


Listen
My baby has low CD3 and CD4 cells. I have consulted a hematologist and was told it is doubtful my baby has SCID. When can we consider it is SCID?

Answer Answer


Listen

The following information may help to address your question:

  • What is severe combined immunodeficiency?
  • How is severe combined immunodeficiency (SCID) diagnosed?

What is severe combined immunodeficiency?

Severe combined immunodeficiencies (SCID) are inherited immune system disorders characterized by abnormalities with responses of both T cells and B cells (specific types of white blood cells needed for immune system function). Common signs and symptoms include an increased susceptibility to infections including ear infections; pneumonia or bronchitis; oral thrush; and diarrhea. Due to recurrent infections, children with SCID do not grow and gain weight as expected (failure to thrive). SCID may be caused by mutations in any of several genes and can be inherited in an X-linked recessive (most commonly) or autosomal recessive manner. The most common type of SCID is called X-linked severe combined immunodeficiency (XSCID). Another form of SCID is caused by a deficiency of the enzyme adenosine deaminase (ADA).[1] Infections are treated with specific antibiotic, antifungal, and antiviral agents and administration of intravenous (IV) immunoglobulin.[2] The most effective treatment is transplantation of blood-forming stem cells from the bone marrow of a healthy person.[1]
Last updated: 6/28/2017

How is severe combined immunodeficiency (SCID) diagnosed?

A diagnosis of SCID may be suspected if a baby shows any of the following persistent symptoms within the first year of life:[3]
  • Eight or more ear infections
  • Two or more cases of pneumonia
  • Infections that do not resolve with antibiotic treatment for two or more months
  • Failure to gain weight or grow normally
  • Infections that require intravenous (IV) antibiotic treatment
  • Deep-seated infections, such as pneumonia that affects an entire lung or an abscess in the liver
  • Persistent thrush in the mouth or throat
  • A family history of immune deficiency or infant deaths due to infections

A diagnosis can be confirmed by blood tests. Blood tests show significantly lower-than-normal levels of T cells and antibodies.[3]  

Since there are other conditions that can result in lower-than-normal numbers of the different types of lymphocytes, the most important tests are those of T-cell function by placing blood lymphocytes in culture tubes, and treating them with various stimulants. Normal T-lymphocytes react to these stimulants by undergoing cell division. In contrast, lymphocytes from patients with SCID usually do not react to these stimuli.

Immunoglobulin levels are usually very low in SCID. Most commonly (but not always), all immunoglobulin classes are depressed (IgG, IgA, IgM and IgE).

The diagnosis of SCID can also be made before the baby is born if there has been another infant in the family with the disorder and if the gene defect has been identified. If genetic analysis had been completed on the infant in the family with SCID, a diagnosis can be determined during subsequent pregnancies. This can be done by molecular testing of cells from a chorionic villous sampling (CVS) or from an amniocentesis, where a small amount of amniotic fluid (which contains fetal cells) is removed.

Early diagnosis, before the infant has had a chance to develop any infections, is very valuable since bone marrow transplants given in the first three months of life have a 94% success rate. In fact, screening newborns to detect SCID soon after birth has been made possible because of recent scientific advances. Approximately half of the babies born in the U.S. are now being screened for SCID.

Last updated: 6/28/2017

We hope this information is helpful. We strongly recommend you discuss this information with your doctor. If you still have questions, please contact us.

Warm regards,
GARD Information Specialist

Please see our Disclaimer.

References References


  1. Learning About Severe Combined Immunodeficiency (SCID). NHGRI. 2014; http://www.genome.gov/13014325.
  2. Hershfield M. Adenosine Deaminase Deficiency. GeneReviews. Mar 2017; http://www.ncbi.nlm.nih.gov/books/NBK1483.
  3. Learning about severe combined immunodeficiency (SCID). National Human Genome Research Institute. July 2010; http://www.genome.gov/13014325.
  4. Severe Combined Immune Deficiency and Combined Immune Deficiency. Immune Deficiency Foundation. 2013; http://primaryimmune.org/about-primary-immunodeficiencies/specific-disease-types/severe-combined-immune-deficiency-and-combined-immune-deficiency/.

Share this content:

Share this content:

twitter-icon facebook-icon contact-icon link-icons

Copy Link

Link copied to your clipboard.

printer-icon

You May Be Interested In

How to Find a Disease Specialist

How to Find a Disease Specialist

Tips for the Undiagnosed

Tips for the Undiagnosed

Support for Patients and Families

Support for Patients and Families

Tips for Finding Financial Aid

Tips for Finding Financial Aid

Help with Travel Costs

Help with Travel Costs

How to Get Involved in Research

How to Get Involved in Research

FAQs About Chromosome Disorders

FAQs About Chromosome Disorders

Medical and Science Glossaries

Medical and Science Glossaries

Caring for Your Patient with a Rare Disease

Caring for Your Patient with a Rare Disease

ICD Coding for Rare Diseases

ICD Coding for Rare Diseases

FindZebra Diagnosis Assist Tool

FindZebra Diagnosis Assist Tool

Finding Funding Opportunities

Finding Funding Opportunities

Teaching Resources

Teaching Resources

placeholder for the horizontal scroll slider Back to top
GARD Home NCATS Home Site Map Browse Glossary A-Z Privacy Notice Disclaimer Accessibility FOIA OIG

If you have problems viewing PDF files, download the latest version of Adobe Reader

For language access assistance, contact the NCATS Public Information Officer

Genetic and Rare Diseases Information Center (GARD) - PO Box 8126, Gaithersburg, MD 20898-8126 - Toll-free: 1-888-205-2311

contact gard Office of Rare Disease Research Facebook Page Office of Rare Disease Research on Twitter
Listen