LONDON -- A transfusion-linked case of variant Creutzfeldt-Jakob disease (vCJD) here has British health authorities increasingly worried about the possibility of a mini-epidemic of the incurable disease from tainted blood.
LONDON, Dec. 8 -- A transfusion-linked case of variant Creutzfeldt-Jakob disease (vCJD) here has British health authorities increasingly worried about the possibility of a mini-epidemic of the incurable disease from tainted blood.
It was the third case of vCJD in an at-risk group who had tainted blood transfusions but the first to be identified before death as having the disease. The patient, a 32-year-old man, developed the disease after a red-cell transfusion donated by a person later determined to have vCJD.
Two cases -- identified after death and reported two years ago -- were previously identified among 66 people who got blood transfusions from donors who subsequently developed vCJD, according to Stephen Wroe, M.D., of the National Prion Clinic at the National Hospital for Neurology and Neurosurgery here.
The report emphasizes the "substantial risk" faced by members of the at-risk group, which is now down to 24, and also "suggests that blood transfusion is an efficient route of transmission of vCJD prion infection," Dr. Wroe and colleagues reported in the Dec. 9 issue of The Lancet.
Of the 66 people who got red-blood cell transfusions from asymptomatic donors who then went on to develop vCJD, 34 died within five years of getting the transfusion because of other diseases. Another eight died more than five years after the transfusion, five of them from other causes.
Three of the eight -- including the most recent case, a 32-year-old man -- were confirmed to have vCJD infection. Another 24 remain alive and are being monitored carefully, the researchers said.
The probability of vCJD occurring in a single person in this group in the absence of transfusion-transmitted infection has been estimated at between one in 15,000 and one in 30,000, Dr. Wroe and colleagues said.
"The probability of chance occurrence of three such cases in this small group is remote," they added.
The report is "important and concerning," said Kumanan Wilson, M.D., of the University Health Network in Toronto and Maura Ricketts, M.D., of the Public Health Agency of Canada in Ottawa.
Writing in an accompanying comment article, Drs. Wilson and Ricketts said the new case "considerably strengthens the inference that transfusion transmission is possible, and suggests that the causative prion can be efficiently transmitted via this route."
The variant form of CJD -- sometimes called mad cow disease -- can be transmitted orally, by eating the flesh of infected animals, and can also be transmitted iatrogenically, for instance in procedures involving tissue transplants.
The two earlier cases in this group involved a 62-year-old who died six years after transfusion. The cause of death was listed as dementia, and post-mortem analysis confirmed CJD. The second was an elderly patient who died of an unrelated cause five years after transfusion; vCJD was confirmed with immunohistochemistry.
The third case was significantly different, in that the disease was identified before the patient's death, the researcher said.
The man had suffered from ulcerative colitis for many years and at age 22 underwent colectomy and ileostomy. A year later, after the ileostomy was converted to an ileoanal J-pouch, complications required 22 units of red cells, 15 units of fresh frozen plasma, and three platelet doses.
One of the donors of the red cells developed vCJD 20 months after giving blood, the researchers said.
Six years after the transfusion, the patient complained of fatigue and impaired concentration, which was attributed to an upper respiratory infection, but about this time, both the patient and his doctor were told of the vCJD-transfusion link.
Neurological, MRI, and encephalogram findings were normal, but a year and a half later, increasing neurological symptoms -- including "searing" leg pain, a tendency to overbalance when turning, and increasing memory difficulty -- led to the man's referral to the National Prion Clinic.
The neurological decline continued at an increasing rate and the patient died eight years and eight months after the transfusion, Dr. Wroe and colleagues reported.
While the report increases concern about the possibility of a blood-borne vCJD epidemic, "the extent of transfusion-transmission of vCJD can not yet be estimated," the researchers said, because the incubation period of prion infections in human beings is long and indeed can exceed 50 years.
Because of that, they said, "the prevalence of asymptomatic infection in the general population of the United Kingdom is therefore unknown."
Two members of the research team are involved in a company that makes a monoclonal antibody used in the study to identify vCJD. The remaining members, including Dr. Wroe, reported no conflicts. Drs. Wilson and Ricketts reported no conflicts.