Blood donation and vCJD

sunnyjim

Was in donating blood today, and was reading the information about the problems with CJD. Over the years the IBTS has taken steps to lower the risk of it being passed on through transfusions. One of the ways was to remove white blood cells from donated blood, as it's a possible route of infection.

So what happens when people donate platelets?

RAFC

Good question, I assume all doners are checked thoroughly first to eliminate any chance of contamination. I enquired about donating platelets last year and was told because I had kids they were no good. Any idea why?

Tree

There are two types of platelet pack: apheresed platelets and pooled platelet rich plasma.

The first is where they hook you up to a machine like a dialysis machine, they take blood out, pass it through filters, remove only the platelets and pump it back into you. They have to like you a lot to ask you to do this, and you have to be a very regular and safe donor. Note that the resultant platelets come from only one donor, these are great for babies and kids.

The second is a byproduct of preparing red cells for transfusion. When you donate your pint of blood, it's separated into half a pint of red cells and a half pint of plasma and pack of platelets and white cells (the buffy coat). The red cells get passed through a white cell filter and they go off to be given to others. The white cell and platlet fraction is kept from selected people, four of these are combined together with a plasma fraction from a fifth donor. This pooled donation is also passed through a white cell filter. These are fine for most patients who need platelets, as the five donors have to meet specific criteria.

Women's white cells and plasma isn't as desirable as men's. If a woman has had kids, there's a fair chance her blood has come into contact w/ her childs blood during labour. This can lead to the mother raising antibodies against the child's cells (in the course of removing htem from the mother's circulation), the white cells that are involved with this can include memory cells, which will produce antibody when introduced to a similar antigen again. So we have a woman who's blood contains white cells that could attack another person's cells. The white cell filters are pretty good, but if they miss a few cells, they can be passed on to the recipient. This can resultant in a condition called TRALI (tranfusion related acute lung injury) which isn't the easiest thing to treat afaik, so to reduce the risk, they dont take the plasma of ladies where possible.

Most plasma used in this country is bought in from abroad in the form of fresh frozen plasma, so the only plasma products from irish donors in regular use is the pooled platelets and fresh frozen plasma when stocks are very low.

RAFC

Women's white cells and plasma isn't as desirable as men's. If a woman has had kids, there's a fair chance her blood has come into contact w/ her childs blood during labour. This can lead to the mother raising antibodies against the child's cells (in the course of removing htem from the mother's circulation), the white cells that are involved with this can include memory cells, which will produce antibody when introduced to a similar antigen again. So we have a woman who's blood contains white cells that could attack another person's cells. The white cell filters are pretty good, but if they miss a few cells, they can be passed on to the recipient. This can resultant in a condition called TRALI (tranfusion related acute lung injury) which isn't the easiest thing to treat afaik, so to reduce the risk, they dont take the plasma of ladies where possible.

Thanks for that, it wasn't explained at the time and was wondering what was wrong with my platelets :cool:

Alun

On this subject, what is the current state of play with regard to vCJD? In other words, is it shaping up to be the problem it was initially suspected to be? I understand that some caution was being used in regard to blood donations because of the long incubation period, but how close are we, if at all, to saying that the danger has passed without the major incidence of the disease that was predicted?

I ask as an ex blood donor excluded because I lived for too long (only by a few months ) in the UK, who'd love to be able to donate again.

Fionnanc

There has not been the explosion of cases of nvCJD that was predicted.

Alun

Fionnanc wrote: »

There has not been the explosion of cases of nvCJD that was predicted.

Exactly, which was the nub of my question I suppose. I assume that at some stage in the future the ban will be lifted, it's only a matter of when.

97i9y3941

bottom line is ,if you lived in the u.k since 1980 you are not allowed to donate blood

Alun

Fred83 wrote: »

bottom line is ,if you lived in the u.k since 1980 you are not allowed to donate blood

[sarcasm mode]
Wow, I didn't know that :rolleyes:
[/sarcasm mode]

Arcee

I get so frustrated by the CJD rule..... everywhere I look I see ads begging for people to donate blood. There are 5 healthy adults in my house, all more than willing to donate but can't because we used to live in the UK.

As far as I'm aware, the risk of transmitting CJD is miniscule, yet a whole portion of the population is excluded. According to the ITB, "To date there have been 200 cases of vCJD worldwide, 4 of which were due to blood transfusion"

I check in with the IBT occasionally but they have no word on when/if the ban will be lifted. :mad::mad:

97i9y3941

they dont know when cjd becomes fully grown,its belived it can be dormant for years,theres safety precautions on surgery equipment too,it must be destroyed,cjd itself is rare,1 in millon chance of developing it

Alun

Fred83 wrote: »

they dont know when cjd becomes fully grown,its belived it can be dormant for years,theres safety precautions on surgery equipment too,it must be destroyed,cjd itself is rare,1 in millon chance of developing it

They've been repeating that self same mantra "for years" (about 20 anyway) too. When are they going to finally admit that they might actually have got it wrong, and that it was all a lot of scaremongering?

Also, it would appear that no-one within the IBTS has ever heard of the term "risk analysis". The chances of anyone who lived in the UK for only a year in that period as I did of contracting vCJD, are so vanishingly small that it's negligible, then multiply that by the chances of anyone actually catching it from a blood transfusion (only 4 cases worldwide, and even then nobody can actually prove conclusively they caught it that way) and you get an even more vanishingly small chance of contracting it via a blood transfusion.

Honestly, you're more at risk driving to the IBTS donation centre than you would be of getting vCJD.

Fionnanc

The infectious particle that causes nvCJD/BSE is an abnormal protein called a prion. This abnormal protein comes into contact with its normal variant in its host changing the normal variant into the prion. These things are incredably difficult to destroy, even with sterilization procedures used on surgical implements. Due to the long incubation period of the illness predictions are difficult.
As a general rule, some people believe the world is going to end soon.- be it due to plague , warfare, divine intervention. Just look at the previous panics with global cooling and ebola virus and CJD and compare with the current hot topics of global warming and MRSA/C diff etc
Rant over

97i9y3941

From sky news

A new version of the human form of mad cow disease could see a second wave of deaths across the UK, according to experts.

Beef on display

The first wave of vCJD deaths were caused by eating infected beef products

It has been revealed that doctors have been treating a patient dying from variant Creutzfeldt-Jakob Disease (vCJD) who appears to have a different gene type from previous British victims.

Scientists say a person's vulnerability to vCJD is determined by genes inherited from their mother and father - either an M or a V.

British victims of the disease have only possessed the gene type MM - about 42% of the population.

Those with MV gene type are thought to be more resistant to the disease, and make up 47% of Britons.

Scientists believe the new patient has an MV gene type, although this cannot be established until a brain biopsy is carried out after death.

The first wave of vCJD deaths, caused by eating infected beef products in the 1980s and early 1990s, has been responsible for 164 deaths, peaking at 28 in 2000.

The possibility of an MV sufferer has prompted fears the illness may have a longer incubation period among this group than among MMs.

This means new victims would only now begin to show symptoms of an infection which was contracted as long as 20 years ago.

Professor Chris Higgins - who chairs the Government's Spongiform Encephalopathy Advisory Committee - told the BBC if the MV case is proved, hundreds of new deaths should be expected.

"This case has not yet been confirmed, but assuming it is, we would estimate that the number of MV cases at a maximum would be about 300 to 350," he said.

"That, I have to emphasise, is a maximum estimate, because all the studies in animals suggest that MV gene types are likely to be far less infective than the MM gene type where we have seen the cases up to now.

"So it is probably between 50 and maybe 350 new cases."

so should we be paranoid about it since most of our meat *sometimes without knowing* is imported?

Alun

So, between 50 and 350 cases (maybe, if they have their facts right) out of a UK population of, what, over 60 million? I'd be more at risk of dying from a lightning strike.

Again, it's all about risk assessment.

Copper

I'd prefer to die from a lightning strike than vCJD though.

We don't know exactly what we're dealing with so it's better to be over cautious than risk contaminating blood stocks - I'd prefer not to get blood off someone who's lived in the U.K.

ZYX

Alun wrote: »

So, between 50 and 350 cases (maybe, if they have their facts right) out of a UK population of, what, over 60 million? I'd be more at risk of dying from a lightning strike.

Again, it's all about risk assessment.

It is all about risk assessment but you are assuming each time a person donates blood only one person benefits. This is not always true. The blood is often used to make "pooled blood products" so a single donation can be then given to hundreds or even thousands of patients. Often people with conditions such as haemophilia. So if vCJD can be transmitted via blood transfusion (which I agree is a big if) then one blood donation from 1 infected person could kill hundreds. Numerous donations from hundreds of people could kill tens of thousands.

Jeapy

Tree wrote: »

If a woman has had kids, there's a fair chance her blood has come into contact w/ her childs blood during labour. This can lead to the mother raising antibodies against the child's cells (in the course of removing htem from the mother's circulation), the white cells that are involved with this can include memory cells, which will produce antibody when introduced to a similar antigen again.

Just to clarify that a little...Say a woman is pregnant and lacks the Rhesus C antigen. Her baby inherits the C antigen from its father. Foetal blood can enter the mother's circulation due to foetal maternal haemorrhage etc and the mother makes anti-C antibodies. These stay in her plasma, so if she were to be used as a platelet donor, these antibodies could be passed on to a patient and cause destruction of all of the transfused cells.

ZYX wrote: »

The blood is often used to make "pooled blood products" so a single donation can be then given to hundreds or even thousands of patients.

FFP comes from American donors for this reason. If it were to be produced in Ireland, the risk of CJD comtamination by one single donor would be too high.