Antibody removal vs best use of the paired pool – what is best?
Dr PD Mason
Transplantation is the best treatment for patients with kidney failure and the sooner
the better. For most patients an early or pre-emptive transplant depends on an
available living donor but up to 35% of potential living donors are incompatible
because of blood group and/or HLA antibodies resulting in a positive cross-match.
The options for these patients are to wait for a compatible deceased donor organ or
consider paired exchange or antibody removal with direct transplantation. Each
option has different risks and costs and paired exchange may be tried before
planning antibody removal. The UK paired exchange programme has been very
successful resulting in nearly 250 transplants by two- or three-way exchanges and
accounted for 5% of all living donor transplants in 2012.
Unfortunately, some patients are very unlikely to find a match for example because
of high cRF with high titres of antibody against common HLA antigens or because
their potential donors’ unfavourable blood group. Antibody incompatible transplants
have also increased in number over the last few years, accounting for 9% of all living
donor transplant in 2012 (5% ABOi and 4% HLAi). The long-term outcome of these is
less certain, especially the HLAi transplants, and patients are generally more heavily
immunosuppressed and the desensitisation protocols are costly. Many factors must
be taken into account before deciding which route is best for an individual donorrecipient pair. These include antibody level, underlying match, likelihood of finding a
match in the paired exchange programme and the predicted probability of removing
sufficient antibody to allow direct transplantation.
Other considerations may also be relevant including how long the patient may have
to wait for a deceased donor organ, especially if they are pre-dialysis, or if there are
significant vascular access problems. For most patients the best option is to try to
find an antibody compatible transplant via the paired exchange programme, but if no
match is found after a few runs, antibody removal should be considered. It is
important that the patient is adequately counselled and encouraged to participate in
the decisions. For the most highly sensitised patients, a combined approach can be
considered to try to find a paired exchange donor to whom the patient still has DSA
but at levels that are easier to remove than against their donor.
The pros and cons and long-term results are discussed.