I want to study the effect of method of delivery on fetomaternal circulation, the ideal indicator is the fetal RBCs in maternal blood, by flow cytometry I found a problem that the expression is high
There are few methods to distinguish between fetal and adult HbF positive cells. One of them is an additional staining with anti CA (carbon anhydrase) antibody. CA is present in adult RBC, and absent in fetal. One color staining is also easy to perform, but you have to use low, high and normal controls to determine accuracy of gating. The pattern you can see in single histogram for HbF staining is high narrow peak for negative cells (mainly HbA), then wide low peak for weak positive cells (when staining thalassemia individuals you will find there many positive cells) and at the end low and narrow peak for fetal cells. Weak positive cells are ca.8%, strong positive for adults should not exceed 0.1%. Without control samples (Fetaltrol) or blood samples from newborn or infant aged less than 3 months, it would be difficult to set gate in proper place.
By the way, you are going to do a study I am currently working on. Wondering, if the results be comparable.
Regards, Olga
It is really important to use high quality reagents - best to start with a commercial anti-fetal Hb test kit if you can afford it. Use a PE-conjugated anti-HbF, as PE gives a much brighter signal than FITC which is important for low abundance cells such as fetal cells in maternal blood. Also you may need to keep in mind that mothers who have certain hematological conditions or inherited traits may have circulating F cells (i.e. red cells that contain lower levels of HbF than found in fetal red cells).
Regards, Rosemary
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