Pregnancy favors circulating IL-21-secreting TFH -like cell recovery in ARV-treated HIV-1-infected women.

PROBLEM: Pregnancy appears to favor maternal antibody production. In contrast, by damaging follicular helper T cells (TFH ), HIV-1 infection compromises protective humoural immune response. Therefore, we aimed to investigate the frequency of different TFH -like cells in HIV-infected pregnant women (PW) before and after antiretroviral (ARV) therapy.

METHOD OF STUDY: Peripheral blood mononuclear cells, CD4+ T and B cells, were obtained from asymptomatic HIV-1-infected non-PW and PW just before and after ARV therapy. In some experiments, healthy HIV-1-negative PW were also tested. The frequency of different TFH -like cell subsets was determined by flow cytometry. The plasma titers of IgG anti-tetanus toxoid (TT), anti-HBsAg, and anti-gp41 were determined by ELISA. The in vitro production of total IgG, IL-21, and hormones (estrogen and progesterone) was quantified also by ELISA.

RESULTS: Our results demonstrate that antiretroviral (ARV) therapy was more efficient in elevating the percentage of circulating IL-21-secreting TFH cells in HIV-1-infected pregnant women (PW) than in non-pregnant patients (nPW). Moreover, in co-culture systems, CD4+ T cells from ART-treated PW were more efficient in assisting B cells to produce IgG production. The in vivo anti-HBsAg IgG titers after ARV therapy were also significantly higher in PW, and their levels were directly associated with both IL-21+ TFH frequency and plasma concentration of estrogen.

CONCLUSION: In summary, our results suggest that pregnancy favors the recovery of TFH -like cells after ARV therapy in HIV-1-infected women, which could help these mothers to protect their newborns from infectious diseases by transferring IgG across the placenta.