Figure 4.

Fetal HLA-polymorphisms used as microchimerism target. The highly polymorphic HLA Class II genes may be used to detect fetal microchimerism. The pregnant woman has two copies of the DRB1 gene, shown as allele 1 and allele 2. The fetus inherits one of these alleles from its biological mother, and one of the alleles from its biological father. The paternally inherited fetal allele may, as in this example, be different from the pregnant woman’s other allele, thereby providing a target for microchimerism detection.