There are two broad categories of chimera: twin and dispermic. Here we report a case of a young girl who was a dispermic chimera and had both group A1 and B red cells in her serum simultaneously.
The patient (H. B.) was a five-year old girl with congenital nevus. She was born by normal delivery as the first child of healthy parents. She had nerve received a transfusion, and there was no evidence of a twin. Her blood contained 96% group B, type MNss red cells and 4% group A1, type NNss red cells. The patient's saliva also contained A and B substances at normal secretor ranges. The level of D-galactosaminyltransferase activity in her serum was within the normal ranges but the level of N-acetyl-d-galactosaminyltransferase activity was at the extreme lower end of the normal range for group A1B persons. One hundred metaphase cells from a culture of the patient's peripheral lymphocytes were all 46, XX. The phenotype of the serum group-specific component (GC) protein of the father was GC2-1S, and of the mother, GC2-1F, but the patient's GC protein was GC1S-1F-(-2). This suggests that the patient's serum contained two populations of GC protein. The sweat gland cells of her scalp tissue stained with both anti-A and anti-B reagents.
These findings demonstrate this child to be a dispermic chimera according to Race and Sanger's classification system.
