The purpose of Working Party is to advise the ISBT, its members, and professionals in the field, on red cell immunogenetics and matters related to terminology and classification of blood group antigens and alleles (see Terms of Reference). One goal of the Working Party (WP) is to adjudicate potential new blood group antigens and blood group systems, and, if accepted, assign names and classifications. A further and subsequent goal of the WP is to maintain the official registry for all recognized blood group systems, antigens and alleles to serve the transfusion community.
Chairperson and committee
Executive committee members:
Co-chairs: Christoph Gassner (Austria) and Catherine Hyland (Australia)
Vice-Chair: Nicole Thornton (UK)
Secretary: Margaret Keller (USA)
Treasurer: Thierry Peyrard (France)
ISBT Board Liaison: Yan Li (China)
Cell-free (cf)DNA Subgroup: Frederik Banch Clausen (Denmark)
Membership
The WP currently comprises 34 members from the Transfusion Community who have a blood group expertise ranging across serological, genetic and genomic and bioinformatic specialities. Members presently represent 13 different countries including Austria, Australia, Brazil, Canada, China, Denmark, England, France, Germany, Israel, Japan, U.S.A and The Netherlands.
Over the last 12 months nominations were received for six candidate new members. An election ballot has been conducted by the ISBT office and new members will soon be announced and welcomed. Their membership terms will commence from June 2026 at the ISBT Congress in Kuala Lumpur, Malaysia.
Executive committee update
The Co-chairs, Secretary, Treasurer and Subgroup will have served the maximum eight-year term in June, 2026. A call for nominations to fill these Executive positions was made in February with nominations closing in March and election ballots planned for April/May 2026.
Meetings
Two formal business meetings and a genomic workshop were held over the last 12 months as follows:
A hybrid (in-person and virtual) business meeting was held in Milan, Italy at the Regional ISBT Congress on Saturday the 31st May. A total of 30 members and seven guests attended.
Key topics discussed included submissions for new blood group systems and antigens. Following rigorous discussion, the meeting voted to accept and register one new system and four new antigens:
- The new system is called PIGZ and is the 48th blood group system reported since the ABO system. PIGZ it therefore designated ISBT 048.
- The four new antigens were within the Knops (KN), Lutheran (LU), Scianna (SC), and Cromer (CROM) blood group systems. The antigen in the KN system was a high prevalence antigen defined initially by an antibody in a male patient. The antigens in the LU and CROM systems were high prevalence defined by antibodies presenting in antenatal patients. The SC was a low prevalence antigen also involving an antenatal patient who developed an antibody which was of major clinical significance.
- A Genomic workshop focusing on the Blood Group Database (in-person and virtual) was also held in Milan, Italy at the Regional ISBT Congress on Sunday 1st June, 2025. The workshop focussed on the development of the new electronic database which was being developed to register all blood group serologic and genomic data. Member of the WP Nick Gleadall and Caroline Hochheuser from the ISBT head office in Amsterdam organised and presented an overview of the database (see Section 5).
The 9th Virtual Working Party Business Meeting was held February 19th, 2026, with 25 members attending.
Key topics discussed included the system for curating the bloodgroupdatabase:
While the official registration for new antigens is addressed during the formal business meetings, the system for approving and registering blood group allelic variants requires a more proactive approach by WP members to fill the gaps. Members are each assigned one or more blood group systems as either the primary “Assignee” or secondary “Reviewer” function to approve and then review/check submissions for new alleles. Only alleles associated with a blood group serology-based phenotype are accepted. Assignees are required to constantly scan published literature and conference abstracts for such alleles.
Executive meetings, (virtual) have been held prior to the business meetings and the Co-chairs continue to meet on a fortnightly or often on a weekly basis.
Activities during the period
Major Projects and Initiatives
- In November 2025, the ISBT launched the ISBT Blood Group Database, ISBT Blood Group Database, as the official digital repository for ISBT blood group nomenclature. This electronic platform replaces the static documentation as the authoritative reference for ISBT-recognized blood group antigen and allele registration and nomenclature. Prior to 2025 the WP members curated the blood group systems, with their respective antigens and alleles, in individual fixed format pdf files.
- The development of this platform was sponsored by the ISBT Board and included a partnership between ISBT and “BloodOmics”.
- This Blood data base serves as an open access reference for immunohematology and hospital blood bank laboratories and for the transfusion medicine community. During the transition phase the members role was to check and monitor the accuracy of the content on the files which were used to transfer data points. While much of the transfer was then automatic quality checks of the final product have been ongoing.
Education and Outreach - for new members:
Following the Milan Business meeting newer members, the WP education officers Vanja Karamatic-Crew and Peter Ligthart prepared a brief “Welcome to the Party” document to both welcome and outline the roles for members.
Member, Greg Denomme, put forward a training and mentoring proposal whereby new members and/or Young Professionals would be instructed on how to curate the content of the blood group antigen and allele tables. This proposal was accepted and subsequent new members will be assigned a “trainer/mentor”.
Working Party Publications
A manuscript was published in Vox Sanguinis. This paper reports four new blood group systems and 13 new antigens ratified during Business meetings held between December 2021 and June 2024.
Summary
In conclusion, the ISBT now registers 371 antigens clustered within the 48 blood group systems with over 2000 allelic variants defined within these systems. The ISBT blooddatabase curation of blood group systems, antigens and associated alleles provides a resource for the Transfusion Medicine community worldwide. The WP members continue to monitor and be responsible for the content of these tables on the ISBT website.
Acknowledgments
We wish to thank the ISBT office for all their support over the last 8 years. A special thank you to the Outgoing Executive Director, Jenny White, for support over the 8 years. A special thank you as well to Caroline Hochheuser who is the ISBT appointed Database Curator and Administrator and provides ongoing expert support to the Working Party members.
A thank you also goes to the Website development Team for the ISBT Blood Group Database goes to Nick Gleadall, William Lane, Barbera Veldhuisen, Shane Grimsley and Caroline Hochheuser.
The Co-chairs and outgoing Executive members also want to thank all members of the RCI&BGT WP for the pleasure and privelege of working with you all over the last eight years.
