Variant CJD and blood transfusion: are there additional cases?

BACKGROUND AND OBJECTIVES

In this study, we compare variant Creutzfeldt-Jakob disease (vCJD) cases definitely linked to blood transfusion, those with a history of blood transfusion in which no donor has developed vCJD and primary cases with no history of blood transfusion. The aim is to determine whether there are any differences in the demographics or clinical phenotype in these groups that might suggest additional cases of transfusion transmission of vCJD.

MATERIALS AND METHODS

All cases of vCJD who are old enough to donate blood (i.e. >17 years old) are notified to the UKBTS at diagnosis, regardless of whether they are known to have a blood donation history. A search is then made for donor records and, if found, all components produced and issued to hospitals are identified and their fate determined. Recipient details are then checked against the NCJDRSU register to establish whether there is a match between these individuals and patients who have been diagnosed with vCJD. In the reverse study, attempts are made to trace the donors to all cases reported to have received a blood transfusion and donors' details are checked against the register to determine if any have developed vCJD.

RESULTS

Of the 177 cases of vCJD diagnosed in the UK as of 1 February 2014, the TMER study identified 15 cases reported to have received a blood transfusion. Transfusion records were unavailable for 4 of these cases, all pre-1980, and in one other case there was no transfusion recorded in the medical notes. Transfusion records were found for 10 cases. One case transfused at symptom onset was excluded from this analysis. The mean age at onset of symptoms of the remaining nine transfusion recipients (four female and five male) was 42·9 years; 57·6 years in the three known transfusion-transmitted cases and 35·5 years in the six not linked cases. In one of these cases, details of components transfused were unavailable, and the remaining five cases received a total of 116 donor exposures with 112 donors identified, none of whom is known to have developed clinical vCJD. To date, five of the 112 identified donors have died and none was certified as dying of vCJD or any other neurological disorder. Two of the transfusion-transmitted cases did not fulfil diagnostic criteria for probable vCJD during life but were confirmed at post-mortem. Both cases were in the older age range (68 and 74 years, respectively), and neither had a positive MRI brain scan. The remaining cases all fulfilled the criteria for the diagnosis of vCJD in life, but two of these had atypical features and were older than the expected age at onset for vCJD.

CONCLUSION

In conclusion, it is possible that one or more of the vCJD cases that received a blood transfusion derived from an individual not known to have vCJD were infected by the blood transfusion. However, the evidence for this is weak, and the absence of a past history of transfusion in most cases of vCJD excludes a large number of unrecognised transfusion-transmitted cases.