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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
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Rh factor is an-
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The correct answer is  RHESUS SYSTEM. The Rhesus (Rh) blood group systemwas first discovered on human red cells by the use of antisera prepared by immunizing rabbits with red cells from a Rhesus monkey. The Rh allelic genes are C or c, D or d, and E or e,located on chromosome 1. One set of 3 genes is inheritedfrom each parent giving rise to various complexcombinations. The corresponding antigens are similarly named Cc, Ee and only D since no d antigen exists. However, out of all these, D antigen is most strongly immunogenic and, therefore, clinically most impoant. In practice, Rh grouping is performed with anti-D antiserum.Individuals who are D-positive are referred to as Rh-positiveand those who lack D antigen are termed Rh-negative.Practically, there are no naturally-occurring Rh antibodies.All Rh antibodies in Rh-negative individuals areacquired from immunization such as by transfusion andduring pregnancy, resulting in fatal hemolytic transfusionreaction and haemolytic disease of the newborn. Ref: Harsh Mohan - Textbook of Pathology, 6th Edition.page no.339