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The British government last week launched a study into the risk that the agent that causes the new variant of Creutzfeldt-Jakob disease (vCJD) might be transmitted by blood, and instructed the National Blood Authority to look at ways of reducing the potential risk.

The moves were announced by Frank Dobson, the health secretary, following advice from the government's Spongiform Encephalopathy Advisory Committee (SEAC). The committee says recent research suggests that the pathogenesis of vCJD differs from that of classical CJD in that the causative agent may occur in particular in lymphocytes, and that it would therefore be “logical” to consider removing such cells from blood products.

SEAC pointed out that while it is so far impossible to assess the risk of transmission of vCJD, risk assessments are urgently needed to obtain a clearer picture. Dobson said his department will carry out a full study immediately, and will consider introducing the leukodepletion of blood, depending on the outcome of the study.

Steve Dealler, a bovine spongiform encephalopathy (BSE) researcher at Burnley General Hospital, who has been campaigning vigorously about the potential risks of contaminated blood (see Transfusion Medicine, 6, 217; 1996), welcomed the government's action, but says that it should have been taken immediately after the risk of BSE passing to humans was acknowledged in March last year.

Dealler and others are sceptical about whether leukodepletion of blood will be sufficient to eliminate all risk, as plasma is likely to be contaminated by leakage from broken cells. The solution would be to screen donors for the disease, he points out, arguing that this makes development of a diagnostic test for vCJD a priority.

Efforts to do so may be helped by the recent discovery of a monoclonal antibody specific for the abnormal version of the prion protein thought to cause the disease (see Nature 390, 74; 1997).

The government “is acting responsibly” in taking a precautionary stance, says Tony Wilson, chief executive officer of the UK Haemophilia Society. But he remains concerned that economic factors may be given excessive weight in the cost-benefit analysis of the safety of blood products. He points out that most UK haemophiliacs are still treated with clotting factors from natural blood, which are inherently more risky than the recombinant alternatives widely used elsewhere, because the natural products are cheaper in Britain.

Meanwhile, the French national bioethics committee last week concluded that while the risk of transmission of vCJD by blood remained “hypothetical”, a body should be set up to monitor scientific knowledge of the risk. Dealler adds that the renewed attention on the risk of blood products suggests it is only a matter of time before European countries raise the question of a ban on exports of British blood products.