Methods for the detection of Jk heterozygotes: interpretations and applications.

The lytic properties of red cells from Jk(a+,b+), Jk(a-, b+) and Jk(a+b-) (normal), Jk(a-b-), and obligate Jk heterozygotes were studied. The Jk(a-b-) cells did not hemolyze for at least 15 minutes in either 2 M urea or methylurea, whereas normal cells were completely hemolyzed in 2 minutes. Red cells from Jk heterozygotes demonstrated intermediate levels of hemolysis when compared to normal and Jk(a-b-) red cells. In addition, these cells had less than 10 percent hemolysis when suspended in 2 M methylurea prepared in 0.4 percent phosphate-buffered saline (pH 7.2). This method may be an alternative to hemagglutination titration scoring for the detection of Jk, especially in paternity cases.