SW Transplant Centre - Changing lives through medical care

SW Transplant

Tissue typing

Tissue typing

Immunology department at Derriford Hospital runs a 24-hour on-call service for transplantation.

All renal patients in the SW transplant centre are tissue typed in the lab and they are regularly monitored for the production of HLA specific antibodies (usually occurring as a result of transplantation, blood transfusions, or pregnancy). Potential live kidney donors are also tissue typed in the lab, followed by pre-transplant cross-matching of the most suitable recipients with donor organs.

 

Virtual Cross-match

Our transplant centre uses virtual cross-match in suitable recipients to minimise cold-ischemia times.

This involves a comparison of the donor’s HLA antigens and the donor’s HLA antibodies (if any). This allows us to predict which cross-matches are likely to be negative and transplant the organs earlier, thus cutting down on cold ischaemia time.

As this requires a recent recipient serum sample, it is very important to have regular samples sent to Immunology for all patients, whether they are being worked up for entry onto the transplant waiting list or already activated.

 

Technique and protocol

Tissue typing is performed by analysing patient’s DNA using the Polymerase Chain Reaction (PCR) technique. Four EDTA tubes (purple top) should be sent for this purpose.

HLA antibodies are detected using panels of known HLA types by flow cytometry, ELISA and lymphocytotoxic methods, which require a further clotted sample (red top) for this purpose.

Patients’ HLA antibody status (quoted as panel reactive antibodies or PRA) can vary due to many factors (especially transfusion, pregnancy and previous transplants).  However, infection can also stimulate an increase in HLA antibody produced by a previous immunising event. For this reason we ask for a clotted sample to be sent every month for all patients. Please also ensure a clotted sample is sent 10-14 days after any known sensitising event (e.g. blood transfusion), with details of the event.

Deceased Donors

Deceased donors may donate within the regional boundaries of SWTC (mainly the South West peninsula), or nationally.

Local donors will be tissue-typed at our lab using both PCR and lymphocytotoxic methods and the results transmitted to UK transplant in Bristol, who will perform a ‘matching run’. This involves a computerised HLA match with all the registered recipients in the UK.

At the time of organ donation samples of donor tissue (usually spleen and/or lymph nodes) are also retrieved and stored with the kidney.

For deceased donors (DCD or DBD) that are transplanted locally a pre-transplant cross-match of donor tissue and the recipient is performed. Fresh and stored serum from the recipient is utilised for this. Stored serum is taken at a time when the panel reactive antibodies (if any) were at their highest level (peak PRA).

The transplant cannot proceed unless the cross-match is negative.

Post-transplant

Post-transplant, patients’ serum is stored from the first few days, and then monthly for the first 3 months, 3 monthly for the first year and annually thereafter. Please ensure a clearly labelled clotted sample is sent to the lab around these times and at any suspected rejection episode.

[These procedures are in accordance with the British Transplant Society guidelines]

 


© SW Transplant 2015 | Tel: South West Transplant Centre | Email: info@swtransplant.com | Privacy and Cookies