Questions and Answers

How often can you do a bone marrow transplant (BMT) for CGD?

Sometimes BMT doesn’t work because the graft fails. It may be possible to consider performing another transplant. However this is dependent on finding another suitable donor and also on the medical condition of the patient considered for subsequent transplant.  There may be a build-up of toxicity in the body from the chemicals used to prepare the body for transplant during chemotherapy that can complicate further attempts at BMT, so if considered, it is usual to wait at least a few weeks-months. Second transplants have been performed successfully for some CGD patients but the numbers are small and as mentioned above, a number of different factors need to be taken into account.

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Is BMT only possible for children with CGD?

No over the past few years more teenagers and adults with CGD have been treated by BMT but the numbers are still low.  One recent major advance has been the development of what is known as ‘reduced intensity conditioning’; this is a milder form of chemotherapy used to prepare the patient for the donor’s bone marrow. This has been used successfully in BMT for adults with different types of primary immunodeficiency. It is likely that more adults with CGD will be treated by BMT in the next few years.

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Why is BMT for adults with CGD more difficult than that for a child?

Usually adults who are being considered for BMT have lots of chronic problems such as lung and gut disease. These chronic problems and chronic infections often make BMT more risky to perform. Also because of the risks of BMT, the choice of whether a BMT is the right thing to do is more difficult especially since adult CGD patients will have jobs, children, etc. This means a lot more factors need to be taken into consideration.


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Can parents be a bone marrow match and so a donor for their child?

BMT works best when there is a 10/10 or 9/10 match of important markers on cells between the donor and the person having the BMT.  A parent may only be a 5/10 or 6/10 match so they not ideal as donors. However, a brother or sister may have a 25% chance of being a match and are often used as donors. Sometimes in consanguineous family parents maybe donors and in this situation the extended family such as aunts and uncles may be tissue-typed.

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What happens if a BMT match cannot be found within the family?

Once doctors have exhausted the possibility of finding a related donor within the family then they will begin the search of a match on national registries such as the Anthony Nolan Registry and cord stem cell banks. Searches can also be made worldwide through international registries. Umbilical cord blood is increasingly being used and this widens the options available.

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How long does it take to find a tissue match?

A match can usually be found within 3 months, although it can take a lot longer. If it takes longer than about 3 months then this usually indicates that it might be difficult, but not impossible, to find a suitable donor.

 

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In a 9/10 tissue match does it matter which one of the markers is mis-matched?

Yes, there are mis-matches that don’t cause problems (permissible), and others that doctors would not consider as a suitable (mis)-match – your consultant will be knowledgeable in this area and will know which mis-matches are acceptable.

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What is a CD4 blood count?

T-cells are important white blood cells that  fight infection and play an important role in immune system function.  CD4 refers to a marker present on a particular sort of T lymphocytes: helper T cells. A CD4 count is a measure of how many T lymphocytes are present in blood and is used as an indication of how well the immune system is recovering post transplant.

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How long does it take for young children to get back up to normal life, for example, attending nursery post BMT?

This depends on how well the child’s immune system has recovered following the BMT. Doctors will be looking at the blood counts, particularly monitoring the number of CD4 cells and this has to return to normal healthy levels before doctors will recommend mixing with other children in the nursery environment.  The amount of time that your child will be off school/nursery will vary, but is normally about 6 months (although sometimes more).


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Can doctors predict who will get graft versus host disease (GvHD) during a BMT and how severe it will be?

A lot of different factors contribute to the risk of GvHD.  These include how closely a donor is matched, what sorts of problems the patient has had before transplant.  This will be discussed with you on an individual basis by your BMT team, but we cannot always predict accurately who will get GvHD, nor how severe it will be. 

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How long can graft versus host disease (GvHD) last?

GvHD can last only a short while if it is mild and responds well to treatment.  However, for some patients it may be harder to treat and last longer.  This is very hard to predict so that it is not possible to give an accurate answer.

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Can you have a BMT when you are pregnant?

This is not possible.

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I’m confused about the term ‘risk’ when considering BMT for CGD. It seems to be used in different contexts. Can you explain?

Risk may mean the chance of a transplant being successful, but it may also be used to mean things that may happen during a transplant e.g. a risk of infection, risk if graft versus host disease.  Your doctors will assess all these risks and discuss them with you.

Results from BMT studies may give an overall indication of how successful or how risky procedures are for a group of people with the same condition. For example, current results for BMT for people with CGD have indicated an overall 90% success rate. That means that within this group there is a risk of one person in ten not having a successful BMT procedure.  However this risk cannot be extrapolated directly to individual patients as BMT carries a personal risk, specific to you based on your medical history and the type and match of the donor.  Doctors will assess this and inform you of the risks relevant to you. 


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