MAB2115 Sigma-AldrichAnti-Cell Surface Antigen of Human Nucleated Erythroid Cells Antibody, clone HAE9

The enrichment of fetal cells, in particular fetal erythroblasts from the blood of pregnant women offers a promising non-invasive alternative for prenatal diagnosis. The purpose of this study was to compare the retrieval of erythroblasts by different density gradients and different antibodies against erythroid surface antigens, in both a model test system and in blood samples of pregnant women. We enriched erythroblasts from artificial mixtures of cord and adult blood (1:50) and from 16 ml of peripheral blood from pregnant women at a mean gestational age of 14+2 weeks. The yield of erythroblasts was calculated and compared using Wilcoxon's matched-pairs signed-rank test. In the artificial mixture most erythroblasts were retrieved using the heaviest density gradient (specific density of 1119) followed by antibody-labelled magnetic cell sorting (MACS). With anti-GPA the yield of erythroblasts from the artificial mixture was highest (9362.5 erythroblasts) compared with anti-CD36 (5164.3), anti-i (3455.2), anti-CD71 (3055.8) and HAE9 (2364.2). The difference between anti-GPA and anti-CD71, HAE9 and anti-i was significant (p=0.0277). The enrichment of erythroblasts from peripheral blood of pregnant women showed similar results. The yield of erythroblasts using anti-GPA was the highest. These results enable us to simplify our enrichment protocols to a single density gradient of 1119 specific density followed by MACS, with anti-GPA.

To date, only anti-glycophorin-A monoclonal antibodies (MAbs) have been widely used as anti-erythroid probes in the diagnosis of leukemias. We have examined blood, bone-marrow and lymph-node samples from 474 patients, adults and children, with different hemopoietic malignancies, using a panel of MAbs including 2 anti-erythroid MAbs directed to glycophorin-A and an antigen of erythroblasts, Ag-Eb. MAb HAE9 directed against a human epitope of Ag-Eb has earlier been shown to be highly specific for immature erythroid cells. Of all the patients, 2.7% demonstrated glycophorin-A expression on blast cells, while anti-Ag-Eb MAb HAE9 reacted positively with cells from 6.0% of patients. Samples from 31 of 474 (6.5%) patients expressed one or both erythroid markers. Our results indicate that MAb HAE9 may be useful, in combination with anti-glycophorin-A MAbs, as an anti-erythroid probe for immunophenotyping human leukemias.