<prompt> Most common antigen involved in erythroblastosis fetalis isC antigen in Rh groupE antigen in Rh groupDuffy antigenD antigen in Rh group  <response>: Erythroblastosis fetalis Hemolytic Disease of the newbornErythroblastosis fetalis is caused by the transplacental passage of maternal antibody active against paternal RBC antigens of the infant and is characterized by an increased rate of RBC destruction Although more than 60 different RBC antigens are capable of eliciting an antibody response, the significant disease is associated primarily D antigen of Rh group and with ABO incompatibility.Other rare antigens involved are - C or E antigen of Rh group o RBC antigens - Cw, Cx, Cu, K kell, M, Duffy, S, P, MNS, Xg, Lutheran, Diego and KiddAnti-Lewis antibodies do not cause disease. 