Project Grant R01HL169401

A PRECISION THERAPY APPROACH TO RED CELL TRANSFUSION FOR SICKLE CELL DISEASE - ABSTRACT RED BLOOD CELL TRANSFUSION REMAINS A LIFE-SAVING THERAPY FOR PATIENTS WITH SICKLE CELL DISEASE (SCD). A MAJOR PROBLEM IS THE HIGH RATE OF ALLOIMMUNIZATION (ANTIBODY FORMATION AGAINST TRANSFUSED RED CELLS) THAT OCCURS IN TRANSFUSED PATIENTS WITH SCD. ALLOIMMUNIZATION LEADS TO DELAYS IN CARE, INCREASES COSTS, AND MAKES TRANSFUSION THERAPY UNSAFE AND IMPOSSIBLE FOR SOME PATIENTS. THE MOST COMMON ANTIBODIES FORMED BY PATIENTS WITH SCD ARE DIRECTED AGAINST THE RH BLOOD GROUP SYSTEM. STUDIES PERFORMED BY OUR GROUP AND OTHERS DEMONSTRATE RH GENETIC VARIANTS IN PATIENTS WITH SCD AND BLACK DONORS IS A MAJOR RISK FACTOR LEADING TO THE HIGH INCIDENCE OF RH ALLOIMMUNIZATION, AND THE COMPLEXITY OF RH ANTIBODY IDENTIFICATION. INHERITANCE OF VARIANT RH ALLELES EXPLAINS APPROXIMATELY ONE-THIRD OF RH ANTIBODIES FORMED BY PATIENTS WITH SCD. THE REMAINDER ARE STIMULATED BY ALTERED RH PROTEINS ON BLACK DONOR RBCS, WHO SHARE SIMILAR RH GENETIC HETEROGENEITY. RECRUITMENT OF BLACK DONORS IS NECESSARY TO SUPPORT PROVISION OF C, E, K NEGATIVE UNITS FOR PATIENTS WITH SCD. IN A PILOT STUDY, WE DEMONSTRATED THE FEASIBILITY OF IDENTIFYING AND TRANSFUSING >300 RH GENOTYPE MATCHED DONOR UNITS TO CHRONICALLY TRANSFUSED PATIENTS WITH SCD. FURTHER STUDIES ARE NOW REQUIRED TO DEMONSTRATE EFFICACY IN PREVENTING RH ALLOIMMUNIZATION. IN ADDITION, A HIGHER-THROUGHPUT RH GENOTYPING METHOD AND INTERPRETATION ARE NEEDED TO FACILITATE TESTING DONORS, WHICH ARE MAJOR BARRIERS TO WIDESPREAD IMPLEMENTATION. LASTLY, THE ABILITY TO IDENTIFY THE SPECIFIC ALTERED RH PROTEIN THAT IS THE TARGET OF THE PATIENT'S IMMUNE RESPONSE AND RESPONSIBLE FOR INCOMPATIBILITY IS CRITICAL FOR SELECTION OF DONOR UNITS. PRECISE IDENTIFICATION OF RH EPITOPES RESPONSIBLE FOR ANTIBODY REACTIVITY IS HAMPERED BY THE LACK OF APPROPRIATE REAGENT RBCS WITH UNCOMMON RH ANTIGEN EXPRESSION. THE MAJOR GOAL OF THIS PROPOSAL IS TO PROVIDE A PRECISION MEDICINE APPROACH TO TRANSFUSION THERAPY FOR SCD BY 1) PROVIDING RH GENOTYPE MATCHED RED CELLS TO CHRONICALLY TRANSFUSED PATIENTS WITH SCD AND DETERMINE THE EFFECT ON RH ANTIBODY FORMATION, 2) TO APPLY NEW NEXT GENERATION SEQUENCING APPROACHES AND DATA ANALYSIS PIPELINES TO IDENTIFY A LOW-COST METHOD TO ACCURATELY IDENTIFY THE COMPLEX RH GENOTYPES IN AFRICAN BLACKS, AND 3) GENETICALLY ENGINEER INDUCED PLURIPOTENT STEM CELLS TO GENERATE RED CELLS THAT EXPRESS VARIANT RH PROTEINS FOR PRECISE ANTIBODY IDENTIFICATION. IN THIS APPLICATION, WE PROPOSE THREE INTEGRATED AIMS THAT CAN ADDRESS THE CURRENT CHALLENGES OF TRANSFUSION THERAPY FOR SCD AND WILL DRIVE THE FIELD FORWARD BY PROVIDING INNOVATIVE SOLUTIONS TO PRECISELY MATCH BLOOD.