A novel method for predicting the presence of anti-Jr antibodies in blood could facilitate the diagnosis of Jr-mediated hemolytic disease of the fetus and newborn (HDFN), according to a recently published study in Annals of Laboratory Medicine.
HDFN is caused by antibodies directed against antigens present on the surface of red blood cells (RBCs). Most cases of HDFN are due to antibodies directed against Rh and ABO antigens.
The Jr antigen is present in over 99% of humans. As antibodies against RBC antigens are created when a person lacking a specific antigen enters in contact with that antigen, anti-Jr antibodies are rare.
“Over the past 50 [years] since the first report, case reports on anti-Jra have been published sporadically,” the authors wrote. “To date, the clinical significance of anti-Jra has not been thoroughly established because of inconsistent clinical outcomes and insufficient data reporting owing to its rarity,”
However, reported cases of Jr HDFN are severe; therefore, there is a need for diagnostic methods to prevent complications in these cases. Currently, anti-Jr testing is only performed in specialized centers.
The authors developed a genetic molecular approach ( TaqMan SNP-genotyping method) based on 2012 research on the genetics of the Jr antigen. They tested the technique in 10 patients suspected of carrying anti-Jr antibodies.
The ten samples were positive for anti-RBC antibodies. Two of the ten samples were sent to international reference laboratories for anti-Jr positivity confirmation. The remainder of the samples were tested with TaqMan SNP, and the results were consistent with those of the control method.
“We validated a rapid, simple, accurate, and cost-effective method for predicting the presence of anti-Jra using a TaqMan-based SNP-genotyping assay,” the authors wrote.” Implementing this method in routine practice in clinical laboratories will assist in solving difficult problems regarding alloantibodies to high-prevalence RBC antigens and ultimately aid in providing safe and timely transfusions and proper patient care,”
