NR AXMM
AU Foster,P.
TI Has vCJD been Transmitted by Human Blood Plasma Products? 20 Years and Counting
QU International Conference - Prion 2007 (26.-28.9.2007) Edinburgh International Conference Centre, Edinburgh, Scotland, UK - Book of Abstracts: Epidemiology, Risk Assessment and Transmission P04.102
IA http://www.prion2007.com/pdf/Prion Book of Abstracts.pdf
PT Konferenz-Poster
AB
The diagnosis of vCJD in a patient whose plasma had previously been used in the preparation of blood plasma products by the NHS led to the decision in 1998 that the preparation of plasma derivatives from UK-donor plasma should cease as a precautionary measure. Since then, plasma products have either been manufactured by the NHS, using plasma purchased from the USA and Europe, or purchased directly from commercial companies.
It is now known that donations from 11 individuals, later diagnosed with vCJD, had been included in the preparation of a total of 175 batches of different plasma products that were released for use between June 1987 and September 1998. No cases of vCJD have been associated with these products, although 20 years have elapsed since the first implicated batches were released for use. This contrasts with 3 instances of probable transmission of vCJD by red cells in which symptoms of vCJD developed in recipients 6.5 years, 7.8 years and 8.3 years after transfusion.
There are a number of possible explanations for the apparent absence of transmision by plasma products.
(1) Prion infectivity was not present in the donated plasma. (2) Prion infectivity was present in the donated plasma but not in the manufactured products, due to dilution or removal of infectivity by the manufacturing process. (3) Prion infectivity was present in manufactured product(s) but has not resulted in clinical symptoms of vCJD because of either a prolonged incubation period or a lack of suceptibility in recipients. The methods used for the manufacture of blood plasma products by the Scottish National Blood Transfusion Service have been examined to determine the extent to which removal of prions might have occurred. These experiments indicate a possible overall prion reduction of 2.7 logs for intermediate-purity factor VIII concentrate (Z8), 3.0 logs for intermediate-purity factor IX concentrate (DEFIX), 5.8 logs for thrombin, >=6.2 logs for fibrinogen, >=6.5 logs for immunoglobulin, 7.4 logs for high-purity factor IX concentrate and >=11.5 logs for albumin.
AD P. Foster, Scottish National Blood Transfusion Service, Protein Fractionation Centre, UK
SP englisch
PO Schottland