Figure 3. Melt curve analysis of the ABO BIS product in patients previously not shown to be methylated by MS-SSCA or COBRA.

The methylated pattern is shown by a dashed line while the unmethylated with a dark black solid line. F9 and F11 both have loss of the A¹ allele but are unmethylated. F10 and F60 '96 are patient samples with no ABO allelic expression and show evidence of methylation by melt curve analysis. F27 is an A¹O¹ patient with loss of the A¹ allele and methylation of 2 different samples, a month apart, which we had previously shown had increasing loss of ABH antigen loss [8] and both showed evidence of methylation.