New molecular strategy to simultaneously determine the major RhD Weak/Parcial variants and RhD zygosity

Abstract

The Rhesus blood system (Rh) is considered the second most important blood group in transfusional medicine. Anti-D antibodies are related to severe complications such as hemolytic reactions and RhD hemolytic disease in the fetus and newborn infant (HDFN). Due to the clinical importance of Rh, serological screening using anti-D monoclonal antibodies is recommended by Brazilian blood banks with the blood donors and receptors. However, in most cases, this method only reveals the presence of an RhD variant, but does not determine exactly which RhD variant type, weak or partial, is present. For the correct determination of RhD variants the use of molecular assays is necessary, but this practice is unfeasible for most Brazilian immunohematology laboratories, because the protocols available are laborious and require the accomplishment of several reactions, needing a long time for the results to appear. Therefore, this study proposes the development of a precise and safe molecular strategy for the detection of major RhD variants in a shorter period of time. This project also involves the creation of a test to determine the RHD zygosity, which is considered essential to assess the risk of HDFN. The implementation of the molecular protocol developed in this study, will optimize the execution time of the tests, resulting in a reduction in the cost of laboratory practices, which are currently considered time-consuming and impractical. The new molecular strategy will also assist research in the area of immunohematology and the clinical staff, avoiding, for example, the indiscriminate use of Rh immunoglobulin in pregnant women with possible risk of HDFN, and the exacerbated use of negative RhD blood without the real necessity.