O Rh factor was discovered in 1940 by two researchers: Landsteiner and Wiener. The discovery came from observations made after putting blood from the ape of the genus rhesus in rabbits.
After applying the monkey's blood, it was noted that the rabbits' blood agglutinated. The explanation for this occurrence was the existence of an antigen in the monkey's blood, so the guinea pigs produced antibodies against the red blood cells received. This antibody was called anti-Rh.
After these observations, the researchers mixed the rabbit serum with human blood. It was noticed there that about 85% of human blood samples agglutinated and only 15% did not. called Rh positive (Rh+) those that agglutinated and, consequently, had antigens in their red blood cells. Those that did not agglutinate received the name of Rh negative (Rh-), as they did not have Rh factor in their red blood cells.
The Rh factor is determined by two alleles that show complete dominance (R and r). Individuals with a dominant allele have the Rh factor in their red blood cells. Those that have two recessive alleles do not have Rh factor. See below a chart that demonstrates the genetics of the Rh system:
Look at the chart above with the genetics of the Rh system
In cases of blood transfusion, we cannot only observe the ABO system, the Rh factor is also essential for the procedure to be performed correctly. When an Rh- person receives Rh+ blood, their body immediately starts producing antibodies. anti-Rh. If another transfusion with Rh+ occurs, the antibodies will attack the red cells, causing them to become break out. Hemolysis can trigger death.
There is also a disease called fetal erythroblastosis, which is characterized by the process of destruction of red blood cells in a fetus, a mechanism similar to that of transfusion explained above. This disease occurs when an Rh- mother begets an Rh+ child. When the mother's blood comes into contact with the baby's, usually at the end of pregnancy, the process of antibody production begins. Production occurs slowly and, therefore, the disease occurs when a new pregnancy occurs and the fetus has Rh+ again, because at that time the amount of antibodies is sufficient to reach the fetus.
By Ma. Vanessa dos Santos
Source: Brazil School - https://brasilescola.uol.com.br/o-que-e/biologia/o-que-e-fator-rh.htm
