Wikipedia:Reference desk/Archives/Science/2020 March 26

= March 26 =

Other blood groups (A, B, AB) can have only once donation from group O?
Group O in blood is a universal donor. Is it correct that it's possible for other blood groups people to get this blood only once at life? I was told so today and I'm not sure if it's a myth or truth.ThePupil (talk) 00:26, 26 March 2020 (UTC)
 * No, what you were told is incorrect. A person with AB, A, or B type blood can receive more than one transfusion of blood type O if necessary. - Nunh-huh 01:35, 26 March 2020 (UTC)


 * And in general it's O-negative that's the universal donor. ←Baseball Bugs What's up, Doc? carrots→ 04:38, 26 March 2020 (UTC)
 * Article: ABO blood group system. If someone hasn't been exposed to non-self ABO antigens, they won't have antibodies against them, and hence won't have an adverse reaction on initial exposure. (This is just like immunity to a pathogen. It's the same mechanism.) But this is not guaranteed because people can become exposed without knowing it. A frequent cause is during pregnancy and childbirth; it's fairly common for some cells to leak across the placenta. If this happens, and the mother and fetus have different blood types, the fetus will be sensitized to the mother's ABO antigen(s). So intentionally infusing non-compatible blood is not done except as an absolute last resort. This same placental leakage, going the other way, is what causes Rh sensitization in mothers. --47.146.63.87 (talk) 07:23, 26 March 2020 (UTC)
 * In general, even people who have never been exposed to blood products are already sensitized to ABO antigens. These are naturally occurring antibodies. In general, people with healthy immune systems are expected to present with naturally occurring ABO antibodies appropriate for their ABO type.
 * This is not simply the result of intrauterine exposure to a discordant mother's blood. A type O child of a type O mother will have anti-A and anti-B antibodies, even though there is no chance that they were exposed to antigens from the mother in utero (since she doesn't have those antigens). The antibodies are thought to be the result of encountering ABO blood group antigens (or antigens that cross-react with them) in foods or microorganisms. "Sugars that are identical to, or very similar to, the ABO blood group antigens are found throughout nature." Another theory is that "these antibodies are genetically coded to be produced even though the body has never been exposed to that antigen before."  - Nunh-huh 07:36, 26 March 2020 (UTC)


 * Are you thinking of rhesus factor instead and hemolytic disease of the newborn ? That's the common case where "second exposure" is the problem, not the first. Andy Dingley (talk) 13:59, 26 March 2020 (UTC)
 * Thank you all for the answers. ThePupil (talk) 20:09, 29 March 2020 (UTC)