Adoptive transfer of CD4+CD25+ regulatory T cells for prevention and treatment of spontaneous abortion

Objectives

The purpose of this study was to examine whether adoptive transfer with in vitro expanded CD4⁺CD25⁺ regulatory T cells (Tregs) could prevent immune response-mediated spontaneous abortion in mice.

Study design

Female CBA/J mice were mated with male Balb/c as the control with normal pregnancy or with DBA/2J mice as a model of spontaneous abortion. The CBA/J mice mated with DBA/2J were treated intravenously with freshly isolated or in vitro expanded Tregs on day 1 or 4 of pregnancy, respectively. The numbers of surviving and reabsorbed fetuses in the different groups of mice were counted on day 14 of pregnancy, and the concentrations of cytokines in individual sera and the supernatants of cultured Tregs were measured by ELISA.

Results

Adoptive transfer with freshly isolated Tregs only slightly reduced the fetal resorption rate, which was not significantly different from that of the mice without Treg treatment, regardless of treatment at early stage and implementation of pregnancy. In contrast, adoptive transfer with in vitro expanded Tregs significantly reduced the fetal resorption rates, particularly for treatment at early stage of pregnancy (P < 0.05). Furthermore, adoptive transfer with in vitro expanded Tregs at early stage of pregnancy significantly increased the levels of serum IL-10, TGF-β1, and the ratios of IL-10 to IFN-γ.

Conclusions

Our data clearly indicated that adoptive transfer with in vitro expanded Tregs at early stage of pregnancy protected fetuses from spontaneous abortion by re-establishing immune tolerance in mice.     

Increased regulatory T cell graft content is associated with improved outcome in haematopoietic stem cell transplantation: a systematic review

Allogeneic haematopoietic stem cell transplant (HSCT) recipients are at increased risk of morbidity and mortality, often due to the development of acute or chronic graft‐versus‐host disease (GVHD). Low numbers or proportions of regulatory T cells (Tregs) have been reported in patients who develop GVHD. We undertook a systematic review of studies that reported the Treg composition of HSCT grafts in patients with haematological malignancies. Fourteen eligible studies were identified, eight of which stratified patients by Tregs (absolute dose or ratio to CD3+ or CD4+ cells). Meta‐analyses showed that high levels of Tregs in the grafts were associated with improved overall survival [hazard ratio (HR) 0·42, 95% confidence interval (CI) 0·23–0·74, P  = 0·003, 2 studies], with a significant reduction in non‐relapse mortality (HR 0·30, 95% CI 0·14–0·64, P  = 0·002, 2 studies) and a reduced risk of acute GVHD (relative risk (RR) 0·59, 95% CI 0·40–0·89, P  = 0·01, 6 studies). The consistency of these findings strongly suggests that the Treg composition of HSCT grafts has a powerful effect on the success of allogeneic HSCT. The major challenge is to translate these findings into better selection of allografts and future donors to provide a substantial improvement in allogeneic HSCT outcomes and practice.