Hello everyone, I hope that this is the best forum to post this topic. I am studying Rh factors, and I have a few questions about this blood type which aren't answered by my textbooks. Thank you very much! --- 1. My textbook says that "anti-Rh antibodies develop over a two to four month period after the transfusion". So, I am wondering, if person A (having Rh- blood), has just received a transfusion from someone with Rh+ blood, will person A be able to receive transfusion safely after this four month period? In other words, will the body continue to produce anti-Rh antibodies if there is no particular contingency for which the antibodies are needed? 2. For blood transfusions, must it be from a positive donor to a negative donor? Or will the other way work as well? I am guessing that it cannot be from - to + because the + will have anti-Rh antibodies which would destroy the negative donor's blood cells?