Severe Combined Immunodeficiency Screening Ready to Launch

The Georgia Public Health Laboratory* is testing now in preparation for ushering in population-based screening by October 2015 for severe combined immunodeficiency (SCID), a rare genetic immune disorder.  Screened as part of a blood spot specimen (heel stick), SCID screening in birthing centers will help identify babies born with little or no immune system.

SCID is characterized by the absence of T and B cells, disabling the body’s ability to fight infections caused by viruses, bacteria or fungi. Even the live viruses in routine childhood vaccines can cause serious, even life-threatening complications.  Thanks to a grant from the Centers for Disease Control and Prevention, early diagnosis and treatment will help affected Georgia infants from dying from severe infections in the first two years of life.

Two to three Georgia infants are born with SCID each year.  More prevalent in boys, SCID is also known as “bubble-boy disease,” named for the Texas boy who lived most of his 12 years of life in a plastic, germ-free bubble.

The blood sample from the newborn undergoes a molecular polymerase chain reaction (PCR) test that allows clinicians to diagnose and monitor serious diseases like SCID.   Using PCR, millions of copies of a section of the newborn’s DNA are made in just a few hours for analysis by measuring T-cell receptor excision circles (TRECs) in the extracted DNA.

If the newborn tests positive for an immune deficient condition, immediate follow-up is required and may warrant isolation to protect the health of the baby.  Family physicians will have access to the hospital-based screening results via SendSS at one week, in time for the baby’s first office visit.   Communicating the urgency for follow-up action to parents of a child with SCID is imperative.   A retest in the physician office may be warranted.

A good outcome is more likely if a bone marrow transplant is done within the first three months of life to help restore a functional immune system before a devastating infection occurs.   When SCID is not detected early, treatment becomes less effective and more expensive.

*The Georgia Public Health Laboratory is vital to population health by providing analytical and technical support to ever-evolving state and federal public health programs through epidemiology, direct program support including laboratory testing for STD, TB and HIV, the Stroke and Heart Attack Prevention Program, and information on legal requirements including mandated newborn metabolic and sickle cell screening.