In Focus
The cfDNA Subgroup
And the story of the noninvasive fetal RhD genotyping
Cell-free DNA (cfDNA) testing is used as a diagnostic tool in several different medical fields including prenatal care, cancer diagnostics, transplantation, and transfusion medicine.
Transfusion medicine is special, because it was here it all started and here that cfDNA testing was used for the first time in a clinical setting—namely in the analysis of cell-free fetal DNA (cffDNA) to predict the fetal RhD type in RhD negative pregnant women. This activity started already in 1998, the same year as cffDNA was discovered. Today, many laboratories around the world offer fetal RHD genotyping, and, in addition, some laboratories also offer testing for other fetal blood group antigens. cfDNA testing is used to assess the risk of hemolytic disease of the fetus and newborn in immunized women, and it can be used to guide anti-D prophylaxis, restricting prophylaxis to D negative pregnant women carrying a D positive fetus.
One fortunate consequence of the early testing activity in transfusion medicine is that our field now harbors a large number of scientists with extensive experience in cfDNA testing (as well as lots of upcoming scientist interested in this area).
The subgroup
In 2018, a subgroup was established as subgroup of the ISBT Working Party for Red Cell Immunogenetics and Blood Group Terminology (RCIBGT). The purpose was to exploit this unique experience and create a forum for sharing knowledge. Today, six years later, the cfDNA Subgroup continues working for the objective of sharing knowledge, collaborating on various projects, and identifying relevant challenges in the field.
The cfDNA Subgroup is led by Frederik Banch Clausen (chair) and Åsa Hellberg. As a subgroup of the RCIBGT Working Party, members of the cfDNA Subgroup are confined to RCIBGT Working Party members. However, every cfDNA Subgroup meeting is open for everyone to attend and contribute. Meetings are held in conjunction with the ISBT congress.
Past work has included formulating recommendations for fetal RHD genotyping (PMID: 34155647). Ongoing work includes a survey to assess the extent of implementation of fetal antigen genotyping across the world. Also included in this survey is identification of topics for future collaboration. For example, technology is a highly interesting topic for the development of reliable fetal antigen genotyping assays. Another very important subject is regulations, especially in Europe, which favor a commercialized testing setup. How to relate to this challenge is not trivial, and it warrants strong collaboration between the experts in our field.
The cfDNA Subgroup thus aims to address future challenges and contribute to the development of clinical applications of cfDNA testing in transfusion medicine.
