Your blood type was discovered in 1901 by a Viennese pathologist.
Mix blood from two people and sometimes the red cells clump together. In 1901 Karl Landsteiner worked out why, sorting human blood into the groups we now call A, B and O. Transfusions between matching groups left the cells intact; mismatches destroyed them. Safe blood transfusion begins here.
Landsteiner was born in Vienna in 1868 and trained in medicine and chemistry. Over a decade at the University of Vienna's pathology institute he reportedly carried out some 3,600 autopsies while publishing dozens of papers on immunity and antibodies. In 1900 he noticed that when blood from two people was mixed, the red cells sometimes stuck together, or agglutinated. The following year he showed that this happened when one person's red cells met another person's serum, the liquid part of the blood.
By testing combinations, he identified three groups, which he labelled A, B and C; the last is now called O. Blood passed between people of the same group left the red cells intact, while mismatched blood led to their destruction. Building on his findings, Reuben Ottenberg carried out what is described as the first successful blood transfusion at Mount Sinai Hospital in New York in 1907.
The logic comes down to markers on the cells and the antibodies that react to them. O-negative red cells carry neither the A nor the B marker, so a recipient's immune system has nothing to attack, which is why O-negative donors are called universal donors. People with group AB make no antibodies against A or B, which makes them universal recipients. In 1927 Landsteiner and Philip Levine found further groups, M, N and P, which were soon used in paternity disputes, and in 1937, with Alexander Wiener, he identified the Rhesus factor, another marker that matters for safe transfusion.
His range was remarkable. In 1909, with Erwin Popper, he showed that polio is infectious and isolated the poliovirus. Hardship in post-war Vienna pushed him to the Netherlands and then, in 1923, to the Rockefeller Institute in New York. He received the Nobel Prize in 1930 and is often called the father of transfusion medicine. Since 2005, World Blood Donor Day has been held on his birthday, 14 June.
Source: Wikipedia — Karl Landsteiner · Text summarised from Wikipedia (CC BY-SA 4.0)
