The 2017 extramural meeting was held in Leipzig, Germany, March 17, 2017, organised by Claudia Lehmann, Ilias Doxiadis and their colleagues.
The first topic on the agenda was an update of the EPT results, presented by Yvonne Zoet (ETRL). Since the September shipment of the EPT was delayed, complete results on typing and crossmatching were not available at the time of the Eurotransplant Annual Meeting.
For HLA typing a discrepancy rate of 1.6% was observed. Note that most discrepancies were made in assigning the correct serological equivalent for B*50:02, which is B45 and not B50. Furthermore, in 2016 it was decided that Bw4 only can be assigned based on the B-locus. Nevertheless, Bw4 was assigned 16 times based on the A-locus.
For crossmatching, discrepancy rates of 3.6% and 3.1% for respective donor centers and recipient centers were observed.
To complete the overview, data from screening detection and screening identification scheme were also shown. For screening detection, a discrepancy rate of 0.5% for HLA class I antibodies, and 1.9% for HLA class II antibodies was observed. For screening identification, CDC and SPA Single Antigen techniques were assessed. In CDC, 14 consensus specificities were found and in SPA SA 422 consensus specificities were found (373 HLA class I and 49 HLA class II).
Next speaker was Sebastiaan Heidt (ETRL), who discussed the three patient-based cases that were send to all EPT participants in 2016. Before the meeting, a summary of results was sent to the participants of the extra mural meeting.
The discussion based on the first patient‐based case was on what to do in case of repeat mismatches in the absence of CDC‐proven DSA and Luminex DSA<1500, and with a negative CDC cross match. The second case was based on the question whether unacceptable antigens should be removed for a highly sensitized HU patient to increase the chance of receiving a transplant? Which antigens (MFI) can be removed? The third case described a patient on the AM waiting list and illustrated that all offers through the AM program are made after an ETRL immunologist on duty has checked the HLA‐ type of both donor and recipient, whether and which unacceptable antigens are present and chance of receiving a transplant. In principle, no AM offers should be denied due to immunological reasons. It was discussed whether AM offers are denied due to these reasons.
News from the TTAC
The meeting continued with Frans Claas, who showed the issues discussed during the TTAC meeting on the 16th of March 2017.
The following recommendation was accepted by the board:
R‐TTAC 03.16 Mandatory donor retyping in recipient center
In order to prevent allocation or transplantation on basis of an incorrect HLA typing to an immunized patient, the recipient center must perform an HLA retyping of the donor in case of an immunized recipient.
The TTAC noticed that logistical problem might occur in case of non‐renal patients. Comments from National societies are awaited, and a remark will be made with respect to the non‐renal organs. Then a point of great concern: The recommendation on the introduction of vPRA (replacing %PRA), as approved by the ET board, still was not approved in Germany. This has the following consequences:
- Patients with %PRA without antibody specificities entered in ENIS have a lot of positive cross matches
- The change of the AM program, from %PRA into chance to receive a donor organ cannot be introduced
An alternative solution was discussed which is non‐mandatory registration of unacceptable antigens on which the vPRA will be calculated.
Closely related to vPRA is virtual crossmatching, while it needs vPRA based on unacceptable mismatches. Virtual crossmatching can be started with non-renal organs. The final aim is doing virtual crossmatching and no longer sending sera to all donor centers.
It was noticed that sometimes crossmatch lists are changed without informing the centers. It seems that the information is given, but only by e-mail, which might not be noticed by the person performing the cross matches. ET will be asked to improve the communication.
The next topic was the introduction of CORE and the immunological parameters required. Wouter Zanen (CORE project leader) was invited to show some of the features, and to discuss new facilities of the CORE program with its users.
The final speaker of the day was Prof. Daniel Seehofer from who showed data of 25 years liver transplantation in the Leipzig region. He showed that in the earlier days survival data were actually better than nowadays. This has several causes, amongst others, the raise of donor age, the use of marginal donors and the introduction of the MELD-liver allocation system.