Treatment of SCID

There are two specialist centres in the UK that treat children with SCID – Great Ormond Street Hospital (GOSH) in London, and the Great North Children’s
Hospital (GNCH) in Newcastle. Treatment will begin when the child is referred
to one of these centres.

The immediate priorities will be to provide an environment which protects from infection, to perform appropriate tests and assessments, and to start treatment for
infection and other protective measures. Subsequently, possible treatments that can correct the defect will be discussed. These include haematopoietic stem cell
transplantation
(HSCT, or SCT; also known as BMT) and gene therapy. HSCT is the most usual treatment, while gene therapy is only suitable in a small number of specific conditions and is still undergoing clinical trials.

Starting treatment

Your child will be admitted to a room or an area with ‘filtered air’ (to remove germs). He or she will be confined to this room and will not be able to mix with other children or go to the ward playroom. You will be able to stay with your child and will be encouraged to continue to feed, care for and play with him or her as much as you want. Visitors will be kept to a minimum, and no one who has an infection will be allowed to visit. You will be told about the ways that you can avoid passing on infection, such as washing your hands thoroughly.

Further blood tests will be performed to confirm the diagnosis and type of SCID. More specialised tests will subsequently be carried out to determine the precise genetic abnormality. Other investigations will also be necessary to identify any
undetected infection, including chest x-rays, scans and tests on samples of
blood, urine, faeces and mucus from the throat.

Most children with SCID will have similar symptoms and will receive the same
treatments whatever the type of SCID. In most cases a ‘central line’ (sometimes called a central venous catheter or Hickman® line) will be inserted. This is a silicone tube which is put into a large vein and fixed to the skin surface, usually on the chest. It requires a small operation under general anaesthetic, but it allows blood to be taken and intravenous medicine to be given without the need for any needles, and is sometimes also used to give intravenous nutrition.

Medication

Antibiotics, antiviral and antifungal medicines will be needed to protect against serious infection. Most medicines can be given in the form of syrups. If the baby has an active infection, it may be necessary to give the medicines into a vein, through a drip (or through the central venous catheter).

Immunoglobulin (antibody) therapy

Babies affected by SCID are not able to produce their own antibodies to fight infection. The missing antibodies are replaced by giving treatment with immunoglobulin.

Immunoglobulin is a solution of human antibodies which have been purified from
normal blood donations. It provides temporary protection against infection and it is given either intravenously (into a vein) or subcutaneously (injection into the skin).

Your child will receive regular immunoglobulin therapy from the time of diagnosis. As it is derived from donor blood, giving immunoglobulin carries a very small risk of transmitting infections. You will have the chance to discuss immunoglobulin therapy in more detail, and the method by which it will be given, with the immunologist or nurse specialist before treatment starts. Further information about immunoglobulin treatment can be found in a range of leaflets from PID UK.

Blood transfusions

It may be necessary to give blood, platelet or plasma transfusions. It is important that these treatments are given, but some precautions are needed. Specially prepared ‘irradiated’ blood is given. Irradiating donor blood preserves the red blood cells and platelets but removes any immune cells that could cause a bad reaction. The donor blood is also screened to ensure it does not contain CMV, which could cause problems for a child with SCID. Any blood, platelet or plasma transfusion will be labelled ‘CMV negative’ and ‘Irradiated’.

CMV, breast feeding and nutrition

CMV is a very common virus in the general population, with approximately 50 to 80 per cent of adults in the UK testing positive for the virus. It is spread through bodily fluids, such as saliva, urine and breast milk. In most cases CMV does not cause any symptoms, but in some people flu-like symptoms, including a high temperature, sore throat and swollen glands, may occur. Once you have had CMV, the virus stays in your body but is inactive, and in a healthy person does not cause any further problems.

CMV can be serious for infants with SCID. If a mother is breastfeeding a child with SCID, a blood test will be taken from the mother to see if she is CMV positive because the virus can be transmitted in breast milk. While waiting for the result, mothers are supported to express their milk. The result normally comes back after 24 to 48 hours. If the result is positive, it is advised to stop breastfeeding, owing to the risk of transmitting CMV to the baby, and formula milk feeds will be recommended. If a baby with SCID is not thriving, extra calories, vitamins and minerals may be needed. These can be given in special drinks or medicines. If your baby is feeding poorly, extra feeds can be given through a nasogastric tube (a tube inserted into the stomach through the nose). However, in some cases it may be necessary to give feeding called TPN (total parenteral nutrition), in which all the nutrients and calories are given intravenously, directly into the bloodstream through a central venous catheter.

Vaccination

In many cases, some early infant vaccines will already have been given before the diagnosis of SCID is recognised. Most of these are completely safe and do not cause any problems because they are not live vaccines. However, it is important for live vaccines to be avoided in infants with SCID. These include live polio vaccine (no longer part of the routine immunisation schedule in the UK), BCG and measles/mumps/rubella (MMR). If your child or another family member has received live polio vaccine due to vaccination in another country, then the doctors should be made aware. Rotavirus vaccine, which has recently been added to the routine UK schedule, is given in the first few months of life, and is also a live vaccine. It may result in the vaccine strain of the virus persisting in the gut of infants with SCID. If your baby has received rotavirus vaccine, this will be tested as part of the initial set of investigations.

Once the diagnosis of SCID is established, no further routine vaccines are recommended until treatment has been completed. Regular immunoglobulin replacement treatment will provide protection against a large number of germs, including those covered by routine vaccines.

Reviewed April 2017