A New Project of Newborn Screening —— Severe Compound Immunodeficiency Syndrome

In recent two years, the number of newborns in Taiwan Province Province has increased, and it is rare to break through the annual 200,000 mark. Everyone must be very excited to have a new member in the family, but then they will inevitably worry: Is the baby healthy? Besides the screening items recommended by the Department of Health, are there any other health examination items that can be done? * * * The same characteristics of the diseases to be screened * * Originally, there were 10 ~ 20 screening items for neonatal genetic and metabolic diseases provided by each hospital, among which silkworm bean disease is the most familiar item, because the prevalence rate of silkworm bean disease in Taiwan Province Province is as high as 3%. Although the prevalence rate of other diseases to be screened is less than one thousandth, they all have the following two characteristics: First, if they are not treated, the condition will be very serious; Second, early diagnosis and treatment of the disease will have a better prognosis.

With the progress of medicine and the development of economy, the number of newborn screening projects in China has gradually increased from 5 in the early days to 20 or 30. In recent months, more and more midwifery hospitals have provided a new neonatal screening program, severe combined immunodeficiency (SCID). The prevalence of SCID is not high. There is only one case of 500,000-500,000 foreign researchers, and the statistics of National Taiwan University are about one in 80,000.

What is "severe compound immunodeficiency"? Our immune system includes cellular immunity and humoral immunity. If both of them are seriously deficient, it is called severe compound immunodeficiency. Antibodies from the mother's umbilical cord can also protect newborns for a period of time. After about three months, these reinforcements were slowly exhausted. SCID patients can't make antibodies to protect themselves, so they are vulnerable to viruses, bacteria or molds, which are manifested as chronic diarrhea, stunting, severe thrush or other mucosal fungal infections, and they are prone to die of serious infections before their first birthday.

SCID comes from genetic abnormality, and at least 10 genes are related to SCID in the form of autosomal recessive or sex-linked inheritance. In addition, due to sexual inheritance, SCID is more common in boys than in girls. Some people may think that my family does not have this inheritance, and my baby can sit back and relax. However, there are also many SCID patients who have no family history and come from gene mutation, so extensive neonatal screening is still meaningful.

A New Project of Newborn Screening —— How to let the baby do SCID screening for severe compound immunodeficiency? At present, the maternity hospital will help the baby collect heel blood for 1 and 20 neonatal metabolic diseases screening. Some hospitals that provide SCID screening services will require parents to fill in a consent form to understand the significance and cost of SCID screening (mostly several hundred yuan at their own expense). If parents agree, you don't have to draw blood for your baby. You can add this item by using a regular heel blood.

What should I do if SCID screening is abnormal? About 7 working days, there will be a screening report. If it is abnormal (positive), you need to go back to the original birth hospital (that is, the original screening hospital) for re-examination (and then help the baby collect blood from the heel of about 0.2). Past experience shows that if the baby is born prematurely (less than 37 weeks), or the baby has undergone chest surgery (the chest tube carrying lymphocytes may be injured during the operation, resulting in insufficient lymphocytes in the blood), it may cause false positives. If the second screening is still abnormal, it needs to be referred to National Taiwan University Hospital for blood test diagnosis. At present, it is roughly estimated that only one out of every 40 infants with positive screening is a SCID patient.

Wait until the screening results are normal before giving BCG. The baby should take at least 10 photos when he is two years old. The principle of vaccine is to let the immune system know about bacteria or viruses that are reduced or inactivated, so as to fight against bacteria or viruses that may be encountered in the future. However, patients with SCID are seriously immune, and they can't even fight the bacteria or viruses with reduced activity in the vaccine. Giving active vaccine to SCID patients will hurt him and cause serious infection.

Our active vaccines include BCG, varicella vaccine, measles, rubella and mumps vaccine and self-funded oral rotavirus vaccine, among which BCG will be vaccinated shortly after birth, so if the baby is screened for SCID, it is best to wait until the result is normal (about seven working days), which also highlights the value of SCID self-funded screening (if you don't screen SCID at your own expense, if the baby is unfortunately a SCID patient,

How should SCID be treated? In addition to avoiding the use of the above active vaccines, SCID patients usually need to take preventive antibiotics and inject immunoglobulin to avoid infection. If infectious diseases have occurred, they must also be actively treated with antibiotics; The final treatment is umbilical cord blood or bone marrow stem cell transplantation.

With the development of medicine, the cure rate of SCID has reached 75 ~ 90%. If the diagnosis can be made three months ago (especially now more and more hospitals provide SCID screening service at their own expense), the success rate of treatment will be higher.