Relationship of Th1/Th2 cell balance with the immune response to influenza vaccine during pregnancy

Abstract

To determine the optimal timing for influenza vaccination in pregnant women, we measured alterations in the types 1 and 2 T helper cell (Th1/Th2) balance during pregnancy, monitored specific immunity to inoculated antigens after vaccination with inactivated influenza vaccine, evaluated the relevance of the Th1/Th2 ratio and immune responses to the vaccination, monitored the maintenance of high antibody titers until delivery and measured the transplacental antibody transfer rate. No significant alterations of the Th1/Th2 balance were noted in the 65% of pregnant women among whom the Th1/Th2 ratio was lower than 9.9% in the first trimester. In those groups with a ratio higher than 10% in the first trimester, there was a tendency for the ratio to decrease as gestation advanced. The efficiency of immunization was not influenced by the Th1/Th2 status or by the stage of gestation. The antibody titer decreased steadily with time from 1 month after vaccination to the time of delivery. Conversely, the transfer rate of antibodies from maternal to fetal blood at the time of delivery increased with the duration of gestation after vaccination. Nevertheless, the antibody titers in both maternal and fetal blood were sufficient to afford protection against infection. Thus, efficient influenza vaccination can be undertaken at any stage of pregnancy.

Serological responses following influenza A H1N1 2009 infection in adults

“…Pregnant women also have an increased disease severity with other infectious diseases such as seasonal influenza and rubella thought to reflect immunologic or other physiological changes in pregnancy. 10,11 The Th1eTh2 shift of pregnancy due to the hormonal environment would, if anything, be expected to increase antibody (Th2) at the expense of cellular (Th1) responses in pregnant subjects. 10 However, of interest, responses to seasonal and H1N1 2009 influenza vaccination have been reported to be well preserved in pregnant subjects.…”

Enhanced natural killer-cell and T-cell responses to influenza A virus during pregnancy

“…Immune responsiveness could change throughout pregnancy, and prior work has proposed a decreasing ratio of type 1 T helper (Th1) to Th2 CD4 + T cells as pregnancy progresses (37). We therefore evaluated whether there were differences in the response to pH1N1 virus between women in their second and third trimester.…”

Influenza, Immune System, and Pregnancy

“…205 A study evaluating the efficiency of influenza vaccination in the second and third trimesters of pregnancy measured the Th1/Th2 balance, maintenance of antibody titers, and transplacental transfer of antibodies to the fetus after vaccination. 206 It was reported that the maintenance of the level of antibody depends on the time elapsed after vaccination, and titers decreased with time irrespective of gestational age. The presence of higher antibody titers in fetal blood may be related to the mechanism of active transfer.…”

“…Vaccination at any gestational age yielded sufficient antibody titers to provide protection against infection, showing that influenza vaccination can be administered at any stage of pregnancy. 206 In a study of a nonlethal murine challenge model, 2 doses of split-virus vaccine were found to be most effective in reducing viral shedding and were associated with high concentrations of prechallenge vaccine-induced serum IgG. Also, irrespective of IgG subclass, high concentrations of serum IgG induced by immunization were an important indicator of the efficacy of the vaccine.…”