Guidance

Clinical pathway for babies who screen positive for SCID

Updated 27 August 2021

Applies to England

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This publication is available at https://www.gov.uk/government/publications/clinical-pathway-for-babies-who-screen-positive-for-scid/clinical-pathway-for-babies-who-screen-positive-for-scid

A description of the process for babies who are screen positive for severe combined immunodeficiency (SCID) following routine NHS newborn blood spot (NBS) screening and are referred into diagnostic services.

Immunology services and teams can use this information to make sure that the babies who need diagnostic testing for SCID are referred and tested in the correct timescales and consistently.

1. Initial notification

Laboratory notifies SCID clinical immunology service (CIS) as per local protocol on the day of the screening result.

2. Urgent actions

The following urgent actions should be completed on the same day as the initial notification (not on Friday if the baby cannot be reviewed the next day). CIS teams should:

3. First appointment

The first appointment should be arranged with an informed expert within 2 working days of contacting the family. The appointment should be face to face, unless the baby is in hospital – in which case it should be conducted virtually. You should inform the family:

  • of the SCID investigation and explain about flow cytometry

  • about the storage, use and analysis of their baby’s data

You should:

  • take a blood sample for the SCID screening lymphocyte subset (see note below) and send to the SCID diagnostic or immunology laboratory

  • confirm their agreement to be contacted to discuss their experience and follow-up outcomes

Note: 0.5 ml EDTA blood will be collected and analysed by flow cytometry using the following markers: CD3, CD19, CD56/16, CD4, CD8, CD45RA, CD27 and DR to detect T cells, B cells, NK cells, CD4 T cells, CD8 T cells, naïve T cells and MHC II expression

4. Review results

The same day or within 1 working day of taking diagnostic samples, you should:

  • review available results

  • communicate results to family with an informed expert

  • make sure CIS informs researchers of family contact details

5. Is the flow cytometry result normal?*

*Flow cytometry normal is defined as >=1,500 CD3/µl AND naïve T cell >=70%

Yes: see and reassure parents, discharge child. Provide discharge information. Confirm consent for follow-up. Send letter to parents (copying in their GP) using the SCID not found letter template for immunology services which includes advice about immunisations. End of pathway.

No: go to question 6.

6. Is flow cytometry <10% naive T cell?

Yes: SCID/Leaky SCID/Omenn Syndrome. You should:

  • refer patient immediately to SCID transplant centre

  • obtain consent for genetic testing to identify the specific SCID type

  • determine maternal CMV IgG status on a fresh blood sample to be able to advise about breast feeding – discontinue breast feeding until results available

  • seek advice from SCID centre about starting co-trimoxazole, fluconazole, and immunoglobulin prophylaxis

  • ideally undertake a definitive procedure within 3 months of diagnosis of SCID

End of pathway.

No: non SCID T Cell Lymphopenia** or secondary causes of TCL*** or idiopathic TCL. You should:

  • follow-up with local paediatric immunology, according to clinical judgement, and refer to geneticist or other subspecialists depending on co-morbidities (for example, cardiologist, paediatric surgeon, community paediatrician)

  • take informed consent for genetics testing

  • perform PID exome panel (Manchester and GOSH)

  • consider referring for genetic counselling if positive genetic result

  • dependent on level of T and other immune cell function, consider starting:
    • co-trimoxazole prophylaxis and anti-fungal
    • antibody replacement

  • make sure patient has all non-live vaccines in first 6 months unless immunoglobulin started (exclude live vaccines, for example BCG, rotavirus, MMR, VZV)

  • follow-up 6 weeks to 3 months depending on level of immune compromise and clinical scenario

End of pathway.

**Non SCID T Cell Lymphopenia includes Nijmegen breakage syndrome, Noonan, CHARGE, Schimke immuno-osseous dysplasia, Down syndrome (trisomy 21), CLOVES, Ataxia telangiectasia, Jacobsen, Tar, DiGeorge, Cytogenetic abnormality, ECC, Cartilage hair hypoplasia, Rac2 defect, Kabuki, Fryns syndrome, Renpenning, Dock8

***Secondary causes of TCL includes congenital heart disease (apart from DiGeorge syndrome), Gastrointestinal malformations such as intestinal lymphangiectasia and hydrops, neonatal leukaemia and HIV

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