The Transfusion Medicine Epidemiology Review (TMER)

Principal Investigators:  Professor RSG Knight (NCJDRSU) and Dr H Harvala-Simmonds (NHS BT) 

The Transfusion Medicine Epidemiology Review (TMER) is a collaborative project between the UK National CJD Research & Surveillance Unit (NCJDRSU) and the UK Blood Services.  The main purpose is to investigate whether there is any evidence that Creutzfeldt-Jakob disease (CJD) or variant Creutzfeldt-Jakob disease (vCJD) may have been transmitted via the blood supply.

METHODS

CJD/vCJD cases (definite and probables) are notified to the UK Blood Services by the National CJD Research & Surveillance Unit.  Donation records are checked and all components traced through hospital records.  Details of all identified recipients are forwarded to the National CJD Research & Surveillance Unit for subsequent checking.

In the reverse procedure, patients with CJD/vCJD reported to have received blood transfusions are traced through hospital records and relevant blood donors identified.  The identity of donors is notified to the NCJDRSU for subsequent checking.

RESULTS (data to 31.12.23)

VARIANT CJD

Thirty-one vCJD cases were reported to have been blood donors.  Four additional cases who were not reported to have been blood donors were found to be registered with UKBTS.  One of these cases was found to have been a blood donor while the other three cases were registered as donors but never made any donations.   Twenty-four of the cases have been traced at blood centres including the four additional cases mentioned above.  Components from 18 of these individuals were actually issued to hospitals.  It has been established that 67 components were transfused to named recipients (56 dead, 11 alive).  

Four instances of probable transfusion transmitted infection have been identified.  The first recipient (Case 1) developed symptoms of vCJD 6½ years after receiving a transfusion of red cells donated 3½ years before the donor (Donor 1) developed symptoms of vCJD.  The second recipient (Case 2) died from a non-neurological disorder 5 years after receiving blood from a donor (Donor 2) who subsequently developed vCJD; protease-resistant prion protein (PrPres) was detected in the spleen but not in the brain.  This is the first recorded case in the UK of autopsy detection of presumed pre- or sub-clinical vCJD infection.  The third recipient (Case 3) developed symptoms of vCJD 7 years, 10 months after receiving a transfusion of red cells donated about 21 months before the donor (Donor 3) developed symptoms of vCJD.   The fourth recipient (Case 4) who also received a transfusion from the same donor as Case 3, developed symptoms of vCJD 8 years, 4 months after receiving a transfusion of red cells donated about 17 months before this donor (Donor 3) developed symptoms of vCJD. (see relevant publications below).

These findings strongly suggest that vCJD may be transmitted via blood transfusion.  The identification of a third case of vCJD in this small cohort of known recipients of blood from persons incubating vCJD establishes beyond reasonable doubt that blood transfusion is a transmission route.

In the reverse study, 15 vCJD cases were reported to have received blood transfusions in the past.  A further case received a blood transfusion after onset of illness. This case is excluded from the figures quoted.  Checks revealed that of these 15 cases, one was not transfused, 4 had transfusions which pre-dated available records (pre 1980), and 10 had records of transfusion which could be traced (see vCJD cases who received blood transfusion(s) in the past below).   These 10 had received 209 donor exposures (with one patient given 103 components), which have been traced to 192 named donors (two of whom had vCJD as described above).  

OTHER FORMS OF CJD

A total of 617 blood transfusion recipients have been identified as having received blood from donors who were later diagnosed with non-variant CJD (sporadic or genetic) forms of CJD.  Of these recipients, 391 are known to have died; there is no evidence that their deaths were related to CJD.

In the reverse study, 310 blood donors were identified whose blood donations had been transfused to patients later diagnosed with sporadic CJD.  Thirteen of these donors have died and there is no evidence that their deaths were related to CJD.

Further data from the study are shown below.  Any enquiries relating to this project can be directed to Jan Mackenzie at jan.mackenzie@ed.ac.uk.