Lack of protection against vertical transmission of HIV-1 by interferons produced during pregnancy in a cohort from East African republic of Malawi.

Abstract

Interferons (IFNs) associated with pregnancy were studied for their possible role in inhibition of vertical transmission of the human immunodeficiency virus type 1 (HIV-1). A study group was composed of 43 HIV-1-positive mothers, of whom 15 transmitted the virus to the offspring and 28 did not. The control group included 48 HIV-1-negative mother-infant pairs. The IFN-alpha was detected only sporadically in the maternal sera from the groups of transmitters (27%), nontransmitters (21%), and controls (19%). The average levels of IFN-alpha were low, 16.3 +/- 2.5 pg/ml, 21.4 +/- 9.9 pg/ml, and 21.3 +/- 9.4 pg/ml among the transmitters, nontransmitters, and control subjects, respectively. In the cord blood, IFN-alpha was detected only on two occasions among transmitters, and on a single occasion in the control group. IFN-beta was absent from both maternal and cord blood in the study group, and found to be present in one case in the control group simultaneously in the maternal and fetal sera. In the placentas, on the other hand, both type I and II IFNs were expressed universally in the villous trophoblast, and IFN-alpha and -beta in the stromal macrophages as well. In one case among transmitters, no IFNs were detected; nevertheless, no significant difference with respect to nontransmitters could be confirmed. Our data suggest that although the placental IFNs have an antiviral potential, they are not sufficient to suppress transmission of HIV from mother to infant.