Presence of IgE cells in human placenta is independent of malaria infection or chorioamnionitis.

We have shown previously that numerous IgE(+) macrophage-like cells are present in the villous stroma of full term placenta and that there was no difference in the amount of IgE(+) cells between allergic and non-allergic mothers. The presence of such an abundant number of IgE(+) cells in the placenta in allergic as well as non-allergic women suggests that the IgE is of some importance for a successful pregnancy outcome. Here we have investigated the IgE-pattern in 59 placentas from second and third trimesters from Sweden with different degrees of chorioamnionitis and 27 full term placentas from Ghana with and without malaria parasites. The immunohistochemical staining pattern for IgE looked similar to our previous study, with the IgE located on Hofbauer-like cells. We could not find any difference in the amount or distribution of IgE(+) cells between malaria-infected and non-infected placentas, nor between different degrees of chorioamnionitis. The IgE score in the placenta did not correlate with the levels of IgE in maternal serum or plasma. However, the IgE score was significantly higher in second- compared to third-trimester placentas (P = 0.03). This might reflect a maturation time-point in the fetus and in the intrauterine environment during the second trimester, or it might be associated with the increased number of intrauterine fetal deaths in the second trimester.