Landsteiner found new blood groups used in paternity cases

Person: Karl Landsteiner
Lived: 1868–1943
Field: Pathology
From: Austrian-American

The story

Karl Landsteiner never stopped studying blood. In 1923, finding little future for research in post-war Vienna, he accepted an invitation, arranged by Simon Flexner, to join the Rockefeller Institute for Medical Research in New York. Through the 1920s he worked on immunity and allergy and returned to the question of how human blood differs from person to person, refining the work he had begun more than twenty years earlier.

His collaborator was Philip Levine, a young physician who had been born near Minsk, grown up in Brooklyn and earned his medical degree at Cornell in 1923. Levine became Landsteiner's assistant at the Rockefeller Institute around 1925.

In 1927 the two men discovered three new blood groups, which they named M, N and P. The groups were independent of the ABO system and showed that human blood was even more varied than anyone had realised. M and N are inherited from a pair of genes in which neither form masks the other, so a person can carry M, N or both. At the Rockefeller Institute, Landsteiner's further work with Levine and later with Alexander Wiener greatly extended the number of known blood groups.

Landsteiner had suggested as early as 1901 to 1903 that because blood group characteristics are inherited, they could help decide cases of doubtful paternity. The new groups made that idea far more practical, because each additional inherited marker narrowed the range of possible parents. Later in the same year, the M, N and P types began to be used in paternity suits.

The MN groups are still part of the wider MNS blood group system, which today includes about 50 known antigens. Levine went on to do important work on the Rh factor and on disease in newborns, and in 1946 he shared a Lasker Award with Landsteiner and Wiener. Blood group testing remained a key tool in family and forensic cases for decades, and it helped lay the groundwork for the idea that inherited markers could identify individuals, an idea later carried much further by DNA testing.