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From: TSS ()
Subject: CJD INCIDENTS PANEL Public summary of the 14th meeting 18th January 2005
Date: November 21, 2005 at 7:39 am PST



Public summary of the 14th meeting

18th January 2005


1. Composition of the meeting

The twelfth meeting of the CJD Incidents Panel was held in London on 18th January. It was attended

by 21 members of the Panel and specialist advisors and observers from the Department of Health

(DH), the devolved administrations and the Health Protection Agency (HPA). The meeting was

chaired by Professor Don Jeffries.

2. Panel appointments

Mr David Pryer had accepted the recent offer of appointment from the Chief Medical Officer

(CMO), on behalf of the UK Chief Medical Officers, as Chairman of the Panel, following a

selection process undertaken by the NHS Appointments Commission. The Chairman thanked Mr

Tullo for his service to the Panel as ophthalmology expert and Professor Roger Buckley who had

acted as alternate to Mr Tullo during the past year; he welcomed Mr Ian Pearce as a new member

and expert in opthalmology. Dr Douglas Russell, a new member nominated by the Royal College of

General Practitioners, was also welcomed.

The Chairman reminded those present that members were appointed to contribute as experts in their

field rather than as representatives of particular organisations, even when nominated by them.

3. Matters arising from the minutes of the previous meeting

3.i Correspondence with President of Royal College of Ophthalmologists

The Panel noted the correspondence with the President of the Royal College of Ophthalmologists. It

had been suggested at the previous meeting that he should be informed about an incident involving

cataract surgery provided by a private company due to concerns which included the lack of surgical

instrument traceability, decontamination standards and the fate of the instruments used.

3.ii TSE transmissions in occupational health settings

The issue of TSE transmissions in occupational settings had been referred to the ACDP TSE

Working Group following the previous meeting. The TSE Working Group’s considered opinion was

that it was highly unlikely that an individual would become infected with CJD following a

needlestick injury. There had been no recorded transmissions of TSEs to humans by this route.

However, the TSE Working Group recognised the need to maintain centrally a secure database of

occupational injuries on a long-term basis . It was agreed that the chairs of the TSE Working Group


and the Panel should send a formal request to the DH to commission surveillance of occupational

exposure to TSEs.

3.iii Clarification of Panel advice about ‘at risk’ patients

At the previous meeting the Panel had agreed that recipients of implicated blood components should

be asked for consent to testing by the National CJD Surveillance Unit of tissue removed during

tonsillectomy, appendicectomy and splenectomy procedures. It had also been suggested that advice

letters from the Panel and the HPA could remind colleagues of the potential value of post mortem

investigations. Clarification was now sought by the Secretariat as to whether these actions should

also apply to other groups at increased risk of developing vCJD as a result of incidents involving

surgical procedures and implicated plasma products. The Panel agreed that a subgroup would meet

to discuss this question and allied issues, including the effect of cultural norms on consent and the

potential contribution of coroners.

4. Quarterly summary of reported incidents

The Panel noted that 12 incidents had been reported to the Panel in the third quarter of 2004,

compared with three in the second quarter.

5. Discussion and endorsement of incidents

5.i Endorsement of advice provided (no precedent)

PI 287

Advice had been requested concerning a service engineer who might have been exposed to CJD

during servicing of an anaesthetic ventilator used on a patient known to have CJD. It had been

withdrawn from use on patients and was being used for training purposes. The Panel advised that

the ventilator could not have been contaminated and therefore the service engineer had not been

exposed to CJD.

Two other advice letters were approved (PI 293 and PI 44/109).

5.ii Incidents involving contactable patients

There had now been 10 incidents in which the Panel had advised the local team to notify patients

that they had been placed in an ‘at risk’ category. Thirty-one patients had been contacted to date (to

the Secretariat’s knowledge).

PI 256


The local team had expressed an initial reluctance to implement Panel advice to notify patients in

relation to this incident concerning an individual with confirmed sporadic CJD; a further letter

reiterating the advice had been sent following discussion at the previous Panel meeting. The Panel

endorsed the letter – advising non-compliance with Panel advice be discussed with the strategic

health authority (SHA). It was pointed out that if a foundation trust (not the case here) did not

follow Panel advice, the SHA would not be the relevant authority to refer to.

PI 259

This incident involved a recipient of implicated blood components found at post mortem to have

evidence of abnormal prion protein in the spleen and a cervical lymph node. A second letter had

conveyed new advice on contacting patients on whom instruments had subsequently been used

following a cataract operation on the index patient. Identification of sets of ‘two subsequent

patients’ for each of the instruments used was advised. The Panel commented on the draft of a third

advice letter following the receipt of precise information concerning the identification of

contactable patients in relation to other procedures.

PI 260

The Panel commented on the draft of a further advice letter in relation to this incident also involving

cataract surgery on a patient with possible sporadic CJD.

PI 267

In this incident involving a recipient of implicated blood components, a second advice letter had

been sent following the Panel decision that recipients of implicated blood components should be

regarded by the Panel as ‘presumed infected with vCJD for public health purposes’. This letter

advised contacting patients on whom instruments had been used following six medium risk

procedures, provided that the first two subsequent patients in relation to each procedure could be

identified: four endoscopies with biopsy; one colonoscopy with polypectomy; and an excision of a

parotid gland tumour (if the instruments had come into contact with lymph nodes).

PI 271

It was reported that, following the Panel advice to contact ‘at risk’ patients on whom instruments

had been used following three cataract operations, the local team were in the process of tracing the

three sets of ‘two subsequent patients’.


5.iii Endorsement of advice provided (based on precedent)

PI 272, PI 275, PI 276, PI 278, PI 279, PI 283, PI 289, PI 291, PI 292, PI 295, PI 296

The Panel endorsed the advice based on precedent on incidents issued from the Panel since the

previous meeting. It was confirmed that the Panel had decided previously that it was not justified to

notify the ‘contacts of contacts’: for example, where a recipient of implicated plasma products had

had neurosurgery, it was advised that there was no need to inform patients on whom the surgical

instruments had been used subsequently.

5.iv Other advice

The Panel noted six other advice letters in response to enquiries concerning matters related to the

Panel remit, although not to specific incidents. Two letters gave prospective infection control

advice. Two letters advised on clinical interventions not considered to be incidents (past procedures

on ‘at risk’ recipients of implicated plasma products).

The fifth letter concerned a query from a patient identified as ‘at risk’ of vCJD who reported that a

surgical procedure had been delayed as a result of their ‘at risk’ status. Whether or not this was in

fact the case, the Panel confirmed the principle in the framework document that there should be no

discrimination arising from the identification of patients as being at increased risk of developing


The sixth letter concerned the marking of paper patient records to ensure information about ‘at risk’

status is available as needed. It was noted that marking manual records could never be 100%

effective and might give rise to concerns about discrimination: effective pre-surgery assessment was

therefore key.

6. DH-funded store for CJD-contaminated instruments

A presentation was given on the store for instruments potentially contaminated with CJD located at

the HPA Centre for Preparedness and Emergency Response, Porton Down. The DH had provided

five years’ funding for the store, until 2007. Its function was to provide secure storage for

potentially contaminated instruments which would otherwise be destroyed by trusts in order that

they might be used for testing methods for CJD detection and decontamination. Potentially

contaminated instruments could be identified to send to the store either immediately following

surgery on a patient known to have or to be at risk of CJD, or during investigation of a Panel

incident. The store was not for the quarantine of instruments, for example, those kept for patients


diagnosed with CJD, or instruments which might be released for normal use following a diagnosis

other than CJD in a patient suspected of having CJD. A protocol had been developed for the

collection and storage of instruments. The Panel supported the need for a second protocol to set out

criteria for evaluation of requests to release instruments for research purposes.

7. Dentistry

7.i Scottish survey of decontamination in general dental practice

A presentation was given on the main findings of the Scottish Survey of Decontamination in

General Dental Practice undertaken by the Glennie Group in collaboration with Health Protection

Scotland. The main objective of the survey had been to look at the decontamination cycle rather

than infection control per se and provide an evidence base for implementing measures to improve

decontamination practice. The findings showed that the cleaning of instruments often did not meet

acceptable standards and was poorly controlled. Cleaning instructions for some instruments had

either not been supplied by manufacturers and suppliers or had not been adjusted for the UK. It was

agreed that the findings were probably representative of primary dental care settings throughout the

UK. The Scottish Executive had used the survey findings to develop a list of 10 ‘priorities for

immediate action’ included in a joint letter from the Chief Medical Officer and Chief Dental Officer

in Scotland. In England and Wales dentistry was included in the NHS strategy for improving

decontamination services and in the current development by NICE of guidance on managing the

risk of transmission of CJD during surgery. Education and collaborative working between dental

practice inspectors and community infection control nurses were identified as important ways of

helping improve decontamination standards in dentistry.

Discussion of the findings concluded that they did not necessarily affect the results of the dental risk

assessment undertaken by the DH. The assumptions used in the analysis of the potential risk of

vCJD transmission through re-use of instruments in dental surgery had taken into account a certain

amount of material adhering to dental instruments following decontamination: now there was

evidence that this was the case.

7.ii Chief Dental Officer’s letter to dentists


Further comments were invited from Panel members on a draft letter for dentists in England

concerning patients with CJD or at increased risk of developing vCJD prepared by the HPA CJD

Section at the request of the Chief Dental Officer.

8. Update on decontamination programmes

8.i England

The National Team had discussed with strategic health authorities (SHAs) how they would take

forward their strategies for improving decontamination, including the use of funds allocated to

improve decontamination in primary care. Some SHAs had held roadshows to explain their strategy

to primary care trusts. A conference would take place in February for professional bodies with an

interest in improving decontamination services. The specification for tracking and tracing systems

drawn up by NHS Estates to help hospitals purchase systems to meet their needs was out for

consultation with the NHS and potential suppliers.

The NHS-funded centre in NE London was expected to open soon and the redevelopment of the

Sterile Services Department at Scarborough was complete. The Healthcare Commission would

include decontamination in their inspections from April 2005. Dental schools had received funding

to improve their decontamination services. The e-learning package developed by NHS Estates for

hospital staff with an interest in good decontamination practice had been launched at a series of

roadshows in the autumn and NHS Estates was hoping to extend this training to primary care staff.

8.ii Northern Ireland

At the request of the Permanent Secretary, the Department for Health and Personal Social Services

(DHPSS) was considering specific actions regarding the decontamination of re-usable medical

devices. This might include an assessment of decontamination policies, procedures and practices for

all re-usable medical devices. The DHPSS was currently considering the Independent Review

Group’s Report into the Systems and Processes of Flexible Endoscope Decontamination in N

Ireland. Following the report by a trust in May 2004 that a gastroscope had been used for over three

years without full compliance with the manufacturer’s instructions on decontamination, the DHPSS

had immediately initiated a wider review to provide complete assurance with respect to the effective

cleaning and decontamination of all endoscopes in use across the HPSS. In July an independent

external review had been commissioned of the systems and processes used within N Ireland to


achieve the cleaning and high-level disinfection of flexible endoscopes following their use in the

investigation and treatment of patients.

8.iii Scotland

It was hoped that 2006 would see the completion of a project whereby Glasgow Hospital had been

funded to build a new central sterilised services department for the whole of the Glasgow area. The

current focus for improvement of decontamination services was on primary care and endoscopy.

8.iv Wales

Of the 17 hospital sterilisation and disinfection units in Wales, the last was expected to achieve

accreditation to the EU Medical Device Directive in March 2005. The Decontamination Project

Board would continue to oversee the accreditation process and planned to issue their final report to

the Health and Social Services Committee of the National Assembly for Wales in March. Funding

for electronic tracking systems for all departments had been included in the programme to improve

decontamination services and these were factored into management systems. Local health boards

were beginning to discuss provision for general medical practices from accredited departments.

One exemplar trust providing decontamination services for GPs in a large part of Wales using the

local ambulance service was now also running a pilot with local dental practices. The initial cost of

providing additional instruments for general practices had been shown to be £500 per practice and

the cost of replacing instruments would be included in the contract. The Decontamination Project

Board had recommended the e-learning package for decontamination commissioned by NHS

Estates, involving the Institute of Sterile Services Managers, for use in Wales. This would be

included in the overall work in relation to healthcare associated infections (HCAIs) which had an

educational component for all aspects of HCAIs.

9. Issues concerning risk from blood products

9.i Report on notification of recipients of plasma products

The Panel received a report on the September 2004 notification of recipients of implicated plasma

products coordinated by the HPA. Preparation for the patient notification exercise had included

working from the Det Norsk Veritas blood risk assessment and manufacturing data to calculate the

risk of implicated plasma products and developing a communication strategy and documentation

tailored to the different groups of health professionals and patients to be involved. During the period


from September until the end of December 2004, the HPA CJD Section had carried out

approximately 1,800 individual patient risk assessments for patients who had received certain

implicated plasma product batches for the treatment of conditions other than bleeding disorders or

primary immunodeficiency. Twelve of these individuals had received sufficient doses to be

considered ‘at risk’ for public health purposes. Further risk assessments would be undertaken as

trusts completed their tracing of recipients of implicated plasma products.

10. Framework document

The Panel commented on a draft revision of the framework document. This revision incorporates

updates in the light of the two recent notifications of implicated blood product recipients; the

agreement of the CMO for England to the establishment of a database of contactable patients; and

other minor updates of fact and wording. It was agreed that a further draft of the revised framework

document would be circulated to Panel members for their detailed comments.

11. Risk assessments: progress report from Department of Health

11.i Endoscopy

A revised version of Annex F to the ACDP TSE Working Group guidance had been posted on the

DH website in September. Enquiries had been received by the Panel Secretariat and the DH

concerning the implementation of this guidance for relatively common endoscopy procedures in

haemophilia patients, eg the treatment of varices associated with hepatitis C. A group had met in

January to discuss this issue. Work continues on defining the invasive procedures performed using

endoscopes , which carry a risk of contamination of the endoscope channel with the CJD agent with

a view to supplementing the guidance in Annex F.

11.ii Revised surgical risk assessment

Since the risk assessment undertaken in 1998/1999, new evidence had been found concerning the

amount of material which remains on surgical instruments following cleaning, but there was still

limited knowledge about the amount of this material attributable to the last patient on whom the

instrument had been used, ie the rate of tissue exchange between instruments and patients. Varying

levels of risk had been estimated in relation to different categories of lymphoid tissue. A revision of

the surgical risk assessment had already been presented to SEAC and NICE and was requested for

the agenda of the next Panel meeting.


11.iii Blood component recipients: ‘reverse’ risk assessment

This risk assessment addressed the question of risk attributable to donors if recipients of their blood

developed vCJD. The probability calculations suggested that, under certain assumptions, in a one

donor to one recipient scenario, donors to vCJD cases could be seen to have a 50% chance of vCJD

infection. It might therefore be consistent with Panel recommendations to consider them ‘at risk’ for

public health purposes. Single transfusions are uncommon: therefore there is usually more than one

donor per recipient. Whilst there was certainty about the fact that blood components from identified

donors had been received by patients who later developed vCJD, there would always be uncertainty

about which donor, if any, was the source of the recipient’s infection, if there were more than one.

To notify large numbers of patients and ask them to take special public health precautions would

run counter to the Panel’s avoidance of informing ‘diluted cohorts’ following surgical incidents. It

was agreed that a small meeting needed to consider the issue and relevant data in more detail,

following consideration by MSBT later in January.

11.iv Breastmilk

There was as yet no evidence of vertical transmission of vCJD via breastmilk and milk banks

excluded donors at increased risk of developing CJD. However, the Panel were asked to consider

whether sufficient precautions were in place to prevent ‘at risk’ patients from donating breastmilk

for other people’s babies, since the standard request to ‘at risk’ patients not to donate ‘tissue and

organs’ did not specifically warn them not to donate breastmilk. It was agreed that the standard

wording in Panel advice letters concerning the public health precautions to be taken by ‘at risk’

patients would not be changed but that the background information developed by the HPA to

support clinicians when informing these patients of their ‘at risk’ status would be amended to

include a reference to breastmilk as well as sperm (already included) in relation to tissue.

12. Items for information

The Panel noted the items included for information.

13. Date of next meeting

11th May 2005 in London.


Annex 1

CJD Incidents Panel Membership (18th January 2005)

Name Expertise


Professor Don Jeffries (acting)

Mr David Pryer (elect)

Deputy Chairman (acting)

Dr Mike Painter


Lay member

Public Health


Mr Adam Balen

Mr John Barker

Professor Mike Bramble

Dr Gerry Bryant

Ms Patricia Cattini

Dr Geoff Craig

Professor Lesley Fallowfield

Dr Calliope (Bobbie) Farsides

Ms Jean Gaffin

Dr Pat Hewitt

Professor James Ironside

Ms Diana Kloss

Professor John Lumley

Mr Henry Marsh

Mr Ian Pearce

Dr Geoff Ridgway

Dr Douglas Russell

Dr Roland Salmon

Dr John Saunders

Dr Peter Simpson

Mr Andrew Tullo (retiring)

Mrs Gillian Turner

Dr Hester Ward

Professor Bob Will

Ms Kate Woodhead

Dr Tim Wyatt

Obstetrics and Gynaecology

Sterile Service Management


Public Health Medicine

Infection Control Nursing

Dental Surgery

Communication with Patients


Lay Representative

Blood Safety

TSE Infectivity, Neuropathology


General Surgery




General Practice


Medical Ethics



Lay Representative



Theatre Nursing



Dr Peter Christie

Ms Carole Fry

Dr Glenda Mock

Dr Mike Simmons

Scottish Executive Health Department

Nursing Officer, Health Protection Division, Department of


Department of Health, Social Services & Public Safety, Northern


National Assembly of Wales


Professor Noel Gill

Dr Kate Soldan

Ms Helen Janecek

Ms Katie Oakley

Health Protection Agency Centre for Infections:

Consultant Epidemiologist

Consultant Scientist

Senior Administrator

CJD Incidents Nurse Investigator


Annex 2

List of Papers





01 Attendee/apology list

02 Draft minutes of 13th meeting on 6th September 2004

03 Draft public summary of 13th meeting on 6th September 2004

04a Correspondence with President of Royal College of Ophthalmologists

04b List of cadre of experts

05 Quarterly summary of reported incidents

06a Advice for endorsement and discussion (without precedent): PI 287, PI 293,

PI 44/109

06b Advice for endorsement and discussion (patients to be contacted): PI 256,

PI 259, PI 260, PI 267, PI 271

06c Advice for endorsement and discussion (with precedent): PI 272, PI 275, PI

276, PI 278, PI 279, PI 283, PI 289, PI 291, PI 292, PI 295, PI 296

06d Other advice for endorsement and discussion

07 Draft protocol for MRC-funded store for vCJD-contaminated instruments

08a Scottish survey of decontamination in general dental practce

08b Correspondence with Chief Dental Officer’s department

08c Chief Dental Officer’s letter to dentists (draft)

09a Update on decontamination in England

09b Update on decontamination in N Ireland

09d Update on decontamination in Wales

10a Report on notification of recipients of plasma products

10b Future notifications – plans and issues for discussion

10c Follow-up of blood component recipients

10e Correspondence with Mr A Tullo

11 Draft revision for comment

12a Endoscopy: Revised Annex F of ACDP TSE Working Group guidance and

correspondence with Mr M Else

12b Blood component recipients: ‘reverse’ risk assessment

12c Organs and tissues: letter to Dr G Thould

13 Draft annual report 2003 to 2004

14 Papers for information


Variant Creutzfeldt-Jakob disease: update LETTER GUT/ENDOSCOPY

-------- Original Message --------
Date: Thu, 11 Nov 2004 09:19:49 -0600
From: "Terry S. Singeltary Sr."
Reply-To: Bovine Spongiform Encephalopathy

##################### Bovine Spongiform Encephalopathy #####################

11-11-2004 08:13

LONDON, November 11 /PRNewswire/ --
- How Safe is the UK Endoscopy Sector?
Sterilox Technologies International, Britain's leading endoscopy and
bacteria-free rinse water specialist, today launched a campaign designed
to raise awareness of the dangers faced by both healthcare workers and
endoscopy patients, and to highlight that there are safe, efficacious
and cost-effective alternatives to the dangerous disinfectants used in
many UK endoscopy units.
The company cites the following sector developments as a catalyst for
its campaign:
June 04 Over 3000 endoscopy patients were recalled in Northern Ireland
following concerns about inadequate disinfection of 15 endoscopes. June
04 A Scottish trust was fined GBP3000 and found guilty of breaking
health and safety regulations by exposing a staff nurse to
glutaraldehyde. June 04 MHRA Alert: risk of transmission of infection
because of inadequate decontamination. May 04 MHRA Alert: repeated
exposure to Cidex(R) OPA following manual re-processing of urological
instruments, may have resulted in hypersensitivity in some patients with
a history of bladder cancer undergoing repeated cystoscopy. December 03
DoH guidelines stating glutaraldehyde and OPA should not be used for any
procedure on patients with a possible diagnosis of CJD or at risk of
developing CJD. October 03 BSG guidelines stating that OPA, peracetic
acid and chlorine dioxide are all potential skin and respiratory
sensitisers requiring the same handling precautions as glutaraldehyde
including fume extraction and PPE. October 03 HSE launched a nationwide
campaign to raise awareness of the adverse impact of working with
substances such as glutaraldehyde - i.e. it causes occupational asthma
and dermatitis.

The campaign will target decision-makers and influencers such as the Rt.
Hon. Dr Reid MP, Secretary of State for Health, the Chief Executives of
Trusts and Infection Control Heads, as well nurses, healthcare workers
and organisation which represent their interests - such as the RCN and
"2004 has to be a watershed for the UK endoscopy sector," commented Paul
Donnelly, Managing Director, Sterilox Technologies International.
"Everyone involved, from patients and medical staff to administrators
and suppliers must now make sure that patients and healthcare workers
will no longer be exposed to unnecessary health risks because we have
the technology, we have the knowledge and we have the expertise to solve
this major problem.
"Over 75% of healthcare workers are exposed unnecessarily to
occupational risks - risks that could be eliminated overnight - and yet
the industry is slow to change.
"Experts, such as Dr David Taylor who is one of Europe's leading
authorities on TSE research, tell us that the risk of patient exposure
to vCJD prions is significantly reduced by using non-fixative single-use
disinfectants, yet many hospitals do not use them. Why?
"We can no longer ignore the lessons of history and there has never been
a better time to make this sector safe - that is what we should all
collectively aim to achieve."
Notes to editors
Sterilox Technologies Inc., is a privately-owned corporation,
established in 1996 and based in Delaware, US. The company's European
headquarters are in Stoke-on Trent, UK.
The company's core product is Sterilox, a safe, fast-acting,
broad-spectrum biocide, often referred to as 'super-oxidized' water.
Sterilox is produced when required using a patented electrolytic cell
from water and common salt (sodium chloride), and the main active
component of the mixture is hypochlorous acid, a powerful disinfectant.
Solutions are fast acting, non-toxic and non-hazardous making them ideal
for the rapid, cold sterilisation of heat-sensitive surgical instruments
such as endoscopes. The company supplies a complete range of generators
and automated washer/disinfectors plus Optident Sterilox, a system
developed specifically for the dental market.
For More Information contact: Simon McKay, TEL +44-(0)1353-741-075,

Copyright: 2004 PR Newswire Europe. All rights to PR Newswire Content
are owned by PR Newswire Association LLC and/or its Affiliates or used
under licence from their licensors. Any copying or other use of PR
Newswire Content including without limitation by caching, framing,
linking or otherwise is expressly forbidden without the prior written
consent of PR Newswire Europe Limited or an appropriate Affiliate

some history on the topic of sporadic CJDs and Endoscopy Equipment ???

From: "Terry S. Singeltary Sr." >

Date: Sat Nov 30, 2002 11:13 am
Subject: Fears over risk from surgical instruments--ENDOSCOPY EQUIPMENT

From: "Terry S. Singeltary Sr." >

Date: Tue Mar 5, 2002 10:37 am
Subject: Re: [CJDVoice] sporadic CJDs and Endoscopy Equipment ???

From: "Terry S. Singeltary Sr." >

Date: Thu Mar 7, 2002 1:03 pm
Subject: ever want to be a fly on the wall??? ENDOSCOPY's AND CJD's or
any TSE

From: "Terry S. Singeltary Sr." >

Date: Mon Aug 27, 2001 2:51 pm
ENDOSCOPES) 'BRILLIANT' just need to use them...

From: "Terry S. Singeltary Sr." >

Date: Sat Aug 25, 2001 11:59 pm
Creutzfeldt-Jakob: all endoscop...


################# #################

Lancet Neurology 2005; 4:805-814


Coexistence of multiple PrPSc types in individuals with Creutzfeldt-Jakob disease

Magdalini Polymenidou a, Katharina Stoeck a, Markus Glatzel a b, Martin Vey c, Anne Bellon c and Adriano Aguzzi a

The molecular typing of sporadic Creutzfeldt-Jakob disease (CJD) is based on the size and glycoform ratio of protease-resistant prion protein (PrPSc), and on PRNP haplotype. On digestion with proteinase K, type 1 and type 2 PrPSc display unglycosylated core fragments of 21 kDa and 19 kDa, resulting from cleavage around amino acids 82 and 97, respectively.

We generated anti-PrP monoclonal antibodies to epitopes immediately preceding the differential proteinase K cleavage sites. These antibodies, which were designated POM2 and POM12, recognise type 1, but not type 2, PrPSc.

We studied 114 brain samples from 70 patients with sporadic CJD and three patients with variant CJD. Every patient classified as CJD type 2, and all variant CJD patients, showed POM2/POM12 reactivity in the cerebellum and other PrPSc-rich brain areas, with a typical PrPSc type 1 migration pattern.

The regular coexistence of multiple PrPSc types in patients with CJD casts doubts on the validity of electrophoretic PrPSc mobilities as surrogates for prion strains, and questions the rational basis of current CJD classifications.


a Institute of Neuropathology, University Hospital Zurich, Switzerland
b Present address: Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
c ZLB Behring, Marburg, Germany

Correspondence to: Dr Adriano Aguzzi, Institute of Neuropathology, University Hospital of Zürich, Schmelzbergstrasse 12, CH-8091 Zürich, Switzerland


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