Altered T Cell Profiles in Uterine Draining Lymph Nodes of Mice with Preterm Labor

Abstract Background: Preterm labor (PTL) is a devastating consequence of fetal interventions such as in utero hematopoietic cell transplantation (IUHCTx). We previously found that PTL after allogeneic IUHCTx is decreased in mice lacking T cells. We hypothesized that the T cell profile in the uterine draining lymph nodes (uLN) would be altered in mothers with PTL. Methods: Mothers carrying semi-allogeneic fetuses underwent IUHCTx at E14.5. At E18.5, we quantified maternal CD4+, CD8+, and CD4+Foxp3+ T cells and measured the production of IL2, IL4, IFN gamma, and IL17 in the uLN, spleen, or non-draining lymph nodes (ndLN). Results: We found equivalent numbers of CD4+ and CD8+ T cells when comparing mothers with and without PTL. We observed a significant increase in the proportion of CD4+Foxp3+ T cells only in the uLN of mothers who experienced complete fetal loss. We also observed equivalent IL2, IFNγ, and IL17 production between all groups. IL4 production by CD4+Foxp3+ T cells was, however, significantly elevated in the uLN of mothers who aborted their entire litter. Conclusions: PTL after fetal intervention leads to expansion of the CD4+Foxp3+ T cell pool in the uLN. The production of IL4 by CD4+Foxp3+ T cells in the uLN suggests that the conversion of these cells to Th2 T effectors may be one potential mechanism by which maternal T cells participate in PTL. Our results support the role of maternal T cells in the pathogenesis of PTL.