Severe
Combined Immunodeficiency, (SCID) commonly known as ‘bubble baby syndrome’ is a
rare inherited disorder where the children have no immune system. A study led by researchers at Great Ormond
Street Hospital NHS Trust (GOSH) and the UCL Institute of Child Health (ICH) in
conjunction with Newcastle General Hospital (NGH) suggests newborn screening for
this condition might greatly improve the chances of survival for these
babies.
Diagnosis
at birth has a significant benefit to those babies affected, researchers at
GOSH/ICH and NGH have found, because they can be shielded from infection and
transplanted earlier and in a more healthy condition.
Researchers
compared the infection rates and survival rates before bone marrow transplant
(BMT), and the survival rate post transplant, between two groups of
children. The first was a group of
children where SCID had not been diagnosed at birth and the second group were
their younger siblings where the previous family history had allowed diagnosis
of SCID at birth.
These
findings are published today in the journal BLOOD (online first).
Professor
Bobby Gaspar, consultant in paediatric immunology and study lead said: “SCID is
a devastating condition and unless treated, children will usually die in the
first year of life. The frequency of SCID in the UK is officially
put at approximately 1:50,000 births, but it may be more frequent than this. In
this study, for the first time, we have been able to show what happens when
babies with SCID are diagnosed at birth. We looked at the outcome of all the
children seen at GOSH/ICH and NGH who were diagnosed at birth because a previous
child was affected. We compared this with the outcome in the older child in the
family who was diagnosed at a later age when they had picked up an
infection.”
Results
from the study were dramatic. In comparison to the older family member with
SCID, babies diagnosed at birth had a significantly decreased number of
infections (89 per cent versus 17 per cent respectively). Patients in the
sibling cohort were also transplanted earlier, and had a dramatically improved
survival outcome following BMT. The study outcomes showed that 35.4 per cent of
the late diagnosed group died before BMT and among the 31 late diagnosed
children that went onto BMT, 38.7 per cent (12 patients) died after the
procedure. In comparison, only 1.7 per cent (one patient) in the sibling group
died before transplant and only 8.5 per cent (five patients) died after
transplant. The transplant survival rate of the sibling group was 91.5 per cent
compared to 61.3 per cent (p<.001) in the late diagnosed
group.
The
findings also show that the improved outcome was not dependent on the precise
type of SCID or the form of ‘conditioning’ (chemotherapy or radiotherapy) used
in the transplant. In principle
researchers expect the same outcome would be found in children offered gene
therapy.
Professor
Gaspar added: “This study clearly shows how important it is to diagnose SCID
early before children have had a chance to pick up an infection. The research
shows that there would be a clear clinical benefit for a screening programme. We
are working towards this in the UK and need to ensure that a quick
and reliable test becomes available.”
Contact information:
For further information,
including interviews with the author and a case study, please call Hayley Dodman or Stephen Cox,
Great
Ormond Street Hospital press office on 0207 239 3126 or
email dodmah@gosh.nhs.uk / coxs@gosh.nhs.uk
For genuine and urgent out of hours call speak to switchboard on 020 7405 9200
