Impact of Hemoglobin S Trait on Cell Surface Antibody Recognition of -Infected Erythrocytes in Pregnancy-Associated Malaria.

Background: Sickle cell trait (HbAS) confers partial protection against malaria by reducing the adhesion of -infected erythrocytes to host receptors, but little is known about its potential protection against placental malaria.

Methods: Using flow cytometry, we assessed the recognition of HbAA and HbAS VAR2CSA-expressing infected erythrocytes, by plasma from 159 Beninese pregnant women with either HbAA (normal) or HbAS. Using multivariate linear models adjusted for gravidity, parasite infection at delivery, glucose-6-phosphate dehydrogenase deficiency, and α-thalassemia carriage, we observed significantly reduced cell surface antibody binding of HbAS-infected erythrocytes by plasma from HbAS compared with HbAA women ( < 10).

Results: The difference in cell surface antibody binding was only observed when infected erythrocytes and plasma were associated according to the same hemoglobin genotype. Similar levels of VAR2CSA-specific antibody were measured by enzyme-linked immunosorbent assay in the 2 groups, suggesting that the altered interaction between VAR2CSA and HbAS women's antibodies could reflect abnormal display of VAR2CSA on HbAS erythrocytes.

Conclusions: Our data stress the need for assessments of erythrocyte disorders such as the sickle cell trait in a population group when studying immunological responses to .