By Billie Rubin, Hemoglobin’s Catabolic Cousin, reporting from the labs of Stanford Blood Center
Most of our blood donors probably already know that the positive or negative after their blood type (A+, B-, for example) represents their Rh factor, an antigen present on the red blood cells of some people. Persons with the factor are designated Rh-positive, those lacking the factor are designated Rh-negative.
Being Rh-positive or Rh-negative really means that either you have the D antigen on your red blood cells or you don’t. Rh(D) is inherited separately from our ABO genes. If you inherit a dominant Rh(D) from one or both of your parents, you are Rh-positive. If you inherit the recessive rh/rh genes from both parents, you are Rh-negative, which represents just 15% the population.
Now here’s something you may not know. It seems we have rabbits and monkeys to thank for the discovery of the Rh system. In the early part of the 1900’s, Karl Landsteiner, who discovered the ABO blood typing system, and Alexander Weiner, an important Rh system researcher, injected some rabbits with blood from rhesus monkeys. The rabbits naturally objected and produced antibodies against the monkey blood. Then an interesting thing happened. That same rabbit antibody against the monkey blood also reacted with some human red blood cells. That’s right, with Rh-positive people, 85% of us to be exact. Don’t you wonder where those two docs got the idea of mixing monkey blood with rabbits?