P1PK blood group system

The P antigen (later renamed P1) was first described by Karl Landsteiner and Philip Levine in 1927.

[1] The P1PK blood group system consists of three glycosphingolipid antigens: Pk, P1 and NOR.

[2][3] In addition to glycosphingolipids, terminal Galα1→4Galβ structures are present on complex-type N-glycans.

It was found that differential binding of transcription factors early growth response 1 (EGR1) and runt-related transcription factor 1 (RUNX1) to the SNP rs5751348[9] genomic region with the different genotypes in the A4GALT gene leads to differential activation of A4GALT expression, leading to two genotypes: P1 and P2.

A test is interpreted as positive only after a patient's red blood cells have been incubated at both temperatures and subsequently hemolyzed.