Summary of the Meeting of the Advisory Committee on Microbiological
Safety Of Blood And Tissues And Organs For Transplantation
24th January 2007
I. Nucleic Acid Testing (NAT) – members were informed that
Ministers had reached a decision on NAT testing and a
letter would be sent to the Committee informing them of the
II. Microbiological testing of blood from organ donors – was
approved for Hepatitis A,B and C, HIV and EBV
III. vCJD precautionary exclusion table - The Committee
approved the revisions to the table
IV. Updates on MHRA Submission on vCJD Diagnostic Assays
– members were informed that Ministerial approval was
obtained to approach to the EU Commission regarding
amendment to the in vitro diagnostic directive.
V. Update on the draft review of MSBTO – The Committee
received a brief summary on the review of MSBTO. The key
proposal was for MSBTO to be replaced by an independent
scientific risk assessment Committee, to be known as the
Advisory Committee on the Safety of Blood, Tissues and
Organs (ACSBTO) and with a broader remit than the current
Progress on prevalence studies, an update on the development of a
diagnostic test for vCJD and the evaluation of prion reduction filters
SEAC Epidemiology Subgroup
• The Spongiform Encephalopathy Advisory Committee (SEAC) position
statement of the SEAC Epidemiology Subgroup on the prevalence of vCJD
in the UK population was considered.
• Due to continued uncertainty about key characteristics of the vCJD epidemic
it was difficult to determine the prevalence of the disease.
Estimation of the prevalence of PrPSc in the British population using a
survey of blood donors
• The National Blood Service (NBS) informed the Committee that the blood
services were proposing to test an aliquot of blood from donors to determine
the prevalence of vCJD in the blood donor population. The study would be
anonymised and could complement the data obtained from the National
Tonsil Archive (NATA) study.
• The Committee was informed that there were a number of potential tests
and the study was designed to select two assays of PrPSc in plasma that use
different capture methods and perform well on spiked evaluation panels
prepared by the National Institute for Biological Standards and Control
• The Committee suggested that the companies interested in developing
screening tests should be asked to re-run the NIBSC evaluation panel and
to ensure that a mechanism was in place for the best 2 tests to be used. The
Committee also suggested that the number of negative control samples
should be increased.
• A member cautioned against extrapolating data from this study to the
general population as the blood donor base was a selected group of
individuals because of the exclusions implemented to safeguard the blood
• The Committee supported this important proposal for estimating the
prevalence of PrPSc but considered it important that it was not linked to the
development of a diagnostic test, which should be independently evaluated,
as was also recommended by SEAC.
Progress on the National Anonoymous Tonsil Archive (NATA) study
• The Health Protection Agency (HPA) gave an update to the Committee on
the NATA study, which was undertaken to better understand the prevalence
of vCJD in the UK population.
• The Committee were informed that the aim of NATA is to collect 100,000
tonsil pairs for PrPSc testing. Currently 40, 000 tonsil pairs have been
collected with a collection rate of about 400 samples per week. A group of
experts, convened by the HPA, recommended the most appropriate high
throughput biochemical tests to analyse these samples for the presence of
abnormal prion protein (PrPSc).
• The Committee were informed that testing of the samples collected will
begin shortly with 10 000 samples from subjects in the 20 to 29 year age
range tested by the end of April 2007. Samples from older and then
younger cohorts would be tested once the results from the 20-29 year cohort
have been completed.
Progress on prion reduction filters
• The NBS gave an update on the UK blood services Prion Reduction
Working Group (PRWG). Members were informed that at least four
companies were developing prion removal technologies. However, only two
companies currently achieved the criteria devised by PRWG, which would
then allow the independent evaluation of the filters.
• MSBTO were informed that the evaluation of the prion reduction filters
involves spiking studies that use a brain homogenate which would take at
least 6 months to prepare before testing of the filters could begin.
• The Committee endorsed the proposed study by the blood services to
evaluate independently the efficacy of prion reduction filters.
The identification of highly transfused patients using epidemiological
• The NBS gave a presentation on data from the study on Epidemiology and
Survival of Transfusion Recipients (EASTR), which could be used to identify
patients who have had more than 80 donor exposures and could be
designated as highly transfused patients (HTP).
• The Scottish National Blood Transfusion Service (SNBTS) gave an update
to the Committee on the Scottish Transfusion Epidemiology Database
(STED) database where it is possible to extract the blood use for each
patient, as the patient’s transfusion records are linked to hospital
procedures. The STED data has patients' transfusion histories from 2002 to
2006 with clinical and deaths data.
• A member informed the Committee that the blood bank computer at his
hospital allowed the transfusion records database to be interrogated to
provide information of blood use for all patients who received red cells,
plasma or platelets.
• A member informed the Committee that the CJD Incidents panel and ACDP-
TSE working group had convened a joint sub-group to investigate the impact
of the identification of HTP. This subgroup will consider a pilot study on how
to identify HTP pre-surgery and how to link the data to other hospital
databases. MSBTO would be kept informed of the deliberations of this sub-
Change to the specification of imported Fresh Frozen Plasma (FFP) for
• MSBTO were asked by NHSBT to consider a number of options for the
future use of FFP, as the single supplier of FFP from the USA could not
ensure continued supplies of FFP by repeat male donors. The Committee
were informed that clinicians prefer to use single donor products and
express the view that that the use of solvent detergent FFP was not ideal as
there was an increased risk with pooling. The Committee was reminded that
the TRALI risk from female donors was also considered to be greater than
the risk from first time male donors.
• The Chair summarised the Committee’s decision to recommend the
continued import of US male FFP but a relaxation of the specification to
include first time donors. However, the Chair stressed the need to
encourage the US supplier to maintain the status quo. In addition, efforts to
ensure the appropriate clinical use of FFP should be continued.
Effect of changes to the permanent deferral criteria to protect recipients
of blood from transfusion transmissible infection (TTI).
• The Committee considered the position statement prepared by the Joint
UKBTS / NIBSC Professional Advisory Committee (JPAC) which
recommended a lifetime exclusion from blood donation for men who
acknowledge that they have had sex with another man. This is done in order
to protect the blood supply from transfusion-transmissible infections. The
statement is available on the JPAC website:
12&pageid=1170 and will be reviewed when the results of further research
• The Committee were informed that the risk of new and emerging agents
needs to be considered and that that the Blood Safety and Quality
Regulations specify permanent exclusion of, " Persons whose sexual
behaviour puts them at high risk of acquiring severe infectious diseases that
can be transmitted by blood" and is available at the following website:
• MSBTO also considered a research proposal on sexual behaviour and blood
donation. The Committee agreed in principle that this was a useful route to
obtaining an evidence base to inform a review of the position of MSBTO on
Consideration of the risk from arboviruses and monitoring of new
• The Committee were informed that the blood services monitor the possible
risk to the blood supply through a variety of means such as, using early alert
reports from the Scientific Committee on Emerging and Newly Identified
Health Risks (SCENIHR), surveillance reports from Program for Monitoring
Emerging Diseases (ProMED), the Health Protection Agency (HPA),
National Expert Panel on New and Emerging Infections (NEPNEI) and
European Blood Alliance (EBA).
• Currently, if the blood services recognise a risk from an arbovirus to the
blood supply in the UK they would request a risk assessment be conducted
by SACTTI which produces individual risk assessments as the need arises.
I. Progress on increasing apheresis platelet collection
• The Committee encouraged the blood services to
continue to increase aphereisis platelet collection.
II. Terms of reference for the MSBTO working group to
review the advice and guidance of the Committee and
the proposed membership.
• The Committee agreed the terms of reference for a
working group to review and update the guidance on the
Microbiological Safety of Human Organs, Tissues and Cells
used in Transplantation, which was published on August