What is the reason why immediate family members can't transfuse each other?

First of all, thank you for your blood type fortune telling. Everyone has clearly known ABO and other different blood types. But in blood transfusion, whether the blood type matches is only one factor. Although the history of blood transfusion can be traced back to BC, it was not until the basic blood type of ABO was determined in the last hundred years that the blood transfusion technology was greatly developed. In essence, the process of blood transfusion is a kind of transplantation, that is, autologous or allogeneic cells, tissues and organs are transplanted into the host to play a role, so blood transfusion is also the earliest cell transplantation. Because transplantation is bound to be accompanied by a series of possible immune responses, transfusion-related graft-versus-host disease (TA-GVHD) is one of the immune responses and one of the most serious transfusion complications. The pathogenesis of TA-GVHD is not completely clear, but it is speculated that TA-GVHD is mediated by lymphocytes in blood transfusion and migrates and proliferates in patients, thus causing serious attacks and destroying patients' immune response. To put it simply, the white blood cells in the blood imported into the human body proliferate wildly and attack the human body, resulting in serious side effects. This is a rare complication of blood transfusion. There is no exact statistical data about the population incidence rate, but it can reach 1% in the immunocompromised population. Unfortunately, there is no specific treatment for TA-GVHD at present, so the mortality rate is very high, and the mortality rate reported at home and abroad is 90% or more.

A few years ago, there was an idol drama called "Next Stop, Happiness", which contained a plot related to this disease. In the plot, Benben is in urgent need of blood transfusion, and VanNess Wu, the hero, originally wanted to step forward, but was stopped because "blood transfusion is not allowed between immediate family members", thus establishing himself as Benben's biological father. I have to say that this screenwriter has made great efforts, because the terrible side effects of blood transfusion in TA-GVHD are much more likely to occur between relatives than between non-relatives. Especially between first-degree relatives, that is, parents and children, the incidence rate is 1 1-2 1 times [1]. Therefore, in order to avoid this disease, blood transfusion between relatives must be eliminated to the greatest extent. However, in many TV series, the story of blood donation when relatives are in trouble is actually contrary to medical common sense.