Meet JAMA: the 49th ISBT blood group system
The Working Party on Red Cell Immunogenetics and Blood Group Terminology ratified a new blood group system at the ISBT Congress in Kuala Lumpur, Malaysia in 2026: JAMA. JAMA is now recognised as the 49th ISBT blood group system. This marks the fifth consecutive year in which at least one new blood group system has been ratified by the Working Party at ISBT Kuala Lumpur 2026.
The discovery of JAMA resulted from a collaboration between teams in Israel and the UK (T Mankelow, L Tilley, V Karamatic Crew, B Jones, M Izak, L Muncher, V Yahalom, N Thornton) following investigations of samples from an Israeli female patient and her brother to determine the specificity of a pan-reactive alloantibody in the patient’s plasma. Combining serological (IAT) and genetic (WES) techniques, the team was able to determine a new high prevalence antigen defined by c.644G in the F11 Receptor gene F11R encoding p.Arg215 in the JAM-A protein. The investigators demonstrated that the absence of this antigen in the samples of the patient and her brother is caused by homozygosity for F11R c.644G>A (p.Arg215Gln), and that immunized individuals can produce an antibody specific to Arg215 JAM-A that binds both red cells and platelets. Their evidence indicates JAM-A represents a novel blood group system, comprising a single high prevalence antigen.
Readers can access the publication “Identification of a novel high-prevalence red blood cell antigen on junctional adhesion molecule-A defines a new blood group system”.
