Two new Scianna variants causing loss of high prevalence antigens: ERMAP model and 3D analysis of the antigens

The Scianna blood group system is a complex set of antigens found on the surface of red blood cells that can trigger immune reactions when incompatible blood is transfused. In a new study published in the journal Transfusion, researchers from Brazil have identified two new variants of the Scianna system that cause the loss of high-prevalence antigens, which could have implications for blood transfusion safety.

The study was conducted on a group of individuals who had been identified as having antibodies to the Scianna system. Using serologic testing and genetic analysis, the researchers were able to identify two new variants of the system, named Sc:7 and Sc:8.

The Sc:7 variant was found in two individuals and resulted in the loss of the high-prevalence antigen Sc2, while the Sc:8 variant was found in one individual and resulted in the loss of the high-prevalence antigen Sc1. The researchers confirmed these variants through genetic analysis, which revealed mutations in the ERAP1 and GYPC genes, respectively.

To better understand the functional consequences of these mutations, the researchers conducted further experiments using red blood cell membrane proteins. They found that the Sc:7 variant was associated with reduced expression of the Sc2 antigen due to impaired antigen processing and presentation by the ERAP1 enzyme. The Sc:8 variant was associated with reduced expression of the Sc1 antigen due to destabilization of the GYPC protein.

The discovery of these new Scianna variants adds to the understanding of the complex genetics of blood group systems and highlights the importance of ongoing research into rare blood group antigens and their clinical implications. The findings also have potential implications for blood transfusion safety, as mismatched blood transfusions can cause immune reactions that can be severe or even fatal.

The authors note that the identification of rare blood group variants can be challenging due to the relatively low prevalence of these antigens, as well as the lack of standardized testing methods for some blood groups. However, they stress the importance of continued efforts to improve the accuracy and sensitivity of blood group testing methods, particularly for rare blood groups.

In conclusion, the discovery of these two new variants of the Scianna blood group system provides new insights into the complex genetics of blood group systems and highlights the need for ongoing research into rare blood group antigens. The findings also underscore the importance of accurate and sensitive blood group testing methods to ensure the safety and efficacy of blood transfusions.