IL17A and tuberculosis: Whilst the role of immunity in successful pregnancy is undoubtedly more complex, involving Treg cells with specificity for allogeneic antigens expressed by the fetus and NK cells [22, 23], HLA-G [24] and macrophages and dendritic cells [25], reduced levels of the pro-inflammatory cytokine IL-17 may also contribute to the likelihood of developing tuberculosis [26–28].