Tonsil Testing

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Headline: NEW CJD FEARS AFTER TEST FINDS DISEASE IN TONSILS

Wire Service: PA (PA News)

Date: Thu, Jan 14, 1999

Copyright 1999 PA News. Copying, storing, redistribution, retransmission,

publication, transfer or commerical exploitation of this information is

expressly forbidden.

By von Radowitz, Medical Correspondent, PA News

Scientists are to test thousands of people for CJD, the human form of

mad cow disease, after discovering evidence in people's tonsils, it emerged

today.

Previously the disease could only be confirmed after victims had died.

The find means it may be possible in the next three years to establish

if a CJD time bomb is ticking within Britain's population.

But it also raises renewed concerns about the risk of infection from

surgical equipment in hospitals, the expert behind the discovery said.

Scientists plan to screen thousands of people using a new test. A

significant positive result would provide early warning of a major epidemic

to come and allow time for action aimed at averting the disaster.

Professor Collinge, from St 's Hospital, London, said today:

" If we were to screen several thousand tonsils and found that several were

positive that would be a real cause for concern. "

The concern about infection raised by the new findings centres on rogue

prion proteins that spread the disease and cannot be cleaned from surgical

instruments no matter how thoroughly they are sterilised.

In future therefore it may be necessary to introduce disposable

instruments for certain procedures. A special committee of experts advising

the Government is already looking at this issue.

Animals studies have shown that spongiform encephalopathy diseases,

which include different forms of CJD, BSE in cattle and the sheep infection

scrapie, tend to reside in the lymph system before attacking the brain.

Tonsils are linked to the lymph system.

The new research by Professor Collinge's team showed this also appeared

to be the way new variant CJD behaved in humans.

But only the new variant form of CJD, which is effectively mad cow

disease transferred to humans through infected beef, was detected in

tonsils.

The " classical " form of CJD, which appears for no known reason in one

person in a million, was not seen in the tissue samples.

The scientists tested tonsil, lymph node and spleen samples taken from

people who had died from various types of CJD and neurological diseases.

Encouraged by the results, they then tested tonsil samples from 20

patients suspected of suffering from CJD.

Nine of the 20 were found to be infected with the new variant disease,

of whom four have since died. Of the nine, only three have been added to

the official statistics. These currently show that 33 confirmed cases of

new variant CJD have occurred in the UK since the disease was identified in

1996.

The results mean that scientists now know they can diagnose new variant

CJD by analysing a surgically removed piece of tonsil tissue. Until now

scientists have had to wait until the death of a patient to find out

definitively if there is CJD infection.

No-one knows at present what the fall-out might be from people eating

BSE-infected beef that was routinely used in burgers and other meat

products before a ban on suspect offals was introduced in 1989.

New variant CJD has a long incubation period which may run into decades,

in which case the trickle of cases seen so far may be just the start of a

flood.

Alternatively if the incubation period is shorter the problem may not

get much worse than it is now.

Professor Collinge, whose research was published today in the Lancet

medical journal, said the new test " offers the possibility that we could

screen tonsils from the population to determine what proportion were

carrying this rogue form of the prion.

" That would give us some idea of the prevalence of new variant CJD,

which is unknown - whether it's going to be a relatively small problem or

whether many thousands are incubating the disease. It may give some advance

warning of a major epidemic. "

With this in mind a screening programme is being planned which will test

tonsils removed in routine operations around the country.

The study, funded by the Medical Research Council and the Government, is

expected to start in about six months.

Professor Collinge admitted he was concerned about the possibility of

new variant CJD being transmitted via infected surgical instruments.

This had always been a theoretical risk. But the conclusive evidence of

tonsil infection meant it was now a real possibility.

But throwing away expensive surgical instruments had to be ruled out

because of the cost, said Professor Collinge.

He added: " There is no means of sterilising surgical instruments

adequately for prions.

" My own view of this is that we may need to consider using more

disposable instruments for certain procedures. "

Experts from the Joint Advisory Committee on Dangerous Pathogens and the

Spongiform Encephalopathy Advisory Committee were now considering the

surgical implications and will be advising the Government about what to do.

Acting on expert advice the Government has already introduced

leucodepletion - removal of white blood cells - for donated blood and

banned the use of British-produced plasma in blood products.

At present there is no cure for new variant CJD, but research has shown

that a drug used in America to treat cystitis may block its spread.

Professor Liam son, the Government's Chief Medical Officer, said

the use of tonsil tissue to diagnose new variant CJD was important but

needed further evaluation.

" The significance of the finding for patients who do not have symptoms

of nvCJD will require further research, " he said.

He added that the experts looking at the issue of surgical instruments

had been asked to consider Prof Collinge's findings and provide advice

about clinical policy.

" Current policy based on advice from the Advisory Committee on Dangerous

Pathogens published in April 1998 is that when any patient with symptoms of

nvCJD, or suspected of having nvCJD, undergoes a surgical operation the

instruments must be removed so that they cannot be used again. "