The K, k, Kpa and Kpb antigens were reported in 1946, 1949, 1957 and 1958 respectively. Kell system antigens are fully developed at birth and the K antigen is very immunogenic. Anti-K, anti-k, anti-Kpa and anti-Kpb have been implicated in Haemolytic Transfusion Reactions and Haemolytic Disease of the Newborn.

The K, k, Kpa and Kpb antigens were reported in 1946, 1949, 1957 and 1958 respectively. Kell system antigens are fully developed at birth and the K antigen is very immunogenic. Anti-K, anti-k, anti-Kpa and anti-Kpb have been implicated in Haemolytic Transfusion Reactions and Haemolytic Disease of the Newborn.

The Lewis system antigens are not an integral part of the red cell membrane and are produced by tissue cells and found primarily in plasma and watery secretions. Red cells acquire Lewis antigens by absorption from surrounding plasma. The amount of Lewis antigen expressed on a cell can vary with the cell’s ABO phenotype. Anti-Lea and Anti-Leb have not been associated with Haemolytic Disease of the Newborn, but examples of Anti-Lea have caused Haemolytic Transfusion Reactions.

The Lewis system antigens are not an integral part of the red cell membrane and are produced by tissue cells and found primarily in plasma and watery secretions. Red cells acquire Lewis antigens by absorption from surrounding plasma. The amount of Lewis antigen expressed on a cell can vary with the cell’s ABO phenotype. Anti-Lea and Anti-Leb have not been associated with Haemolytic Disease of the Newborn, but examples of Anti-Lea have caused Haemolytic Transfusion Reactions.

The Lua and Lub antigens were reported in 1945. The expression of the antigens on the red cells can vary widely from person to person. Anti-Lua is not generally associated with Haemolytic Transfusion Reactions but anti-Lub has been. Both anti-Lua and anti-Lub have been implicated in Haemolytic Disease of Newborn.

M antigen is part of the MNS system and was first reported in 1927. M antigen expression on red cells can show dosage. Anti-M has rarely been implicated in Haemolytic Disease of the Newborn or in Haemolytic Transfusion Reactions.

Landsteiner discovered the P1 antigen in 1927. Anti-P1 does not generally react above room temperature and may often go undetected in routine testing. Anti-P1 does not cause Haemolytic Disease of the Newborn and has only rarely been associated with Haemolytic Transfusion Reactions.

The S and s antigens were reported in 1947 and 1951 respectively and form part of the MNS system. Anti-S and anti-s have both been implicated in Haemolytic Transfusion Reactions and Haemolytic Disease of the Newborn.

The Fya and Fyb antigens were reported in 1950 and 1951 respectively. Anti-Fya and anti-Fyb have both been implicated in immediate and delayed Haemolytic Transfusion Reactions and Haemolytic Disease of the Newborn.

The S and s antigens were reported in 1947 and 1951 respectively and form part
of the MNS system. Anti-S and anti-s have both been implicated in Haemolytic
Transfusion Reactions and Haemolytic Disease of the Newborn.