Gomez-Lopez N, Romero R, Galaz J, et al. - Given that preterm birth is usually preceded by preterm labor, a syndrome that is causally associated with both intra-amniotic infection and intra-amniotic inflammation, researchers intended to better understand the stereotypical cellular immune responses in these two clinical conditions. From women diagnosed with preterm labor and intra-amniotic infection (n = 10) or intra-amniotic inflammation (n = 16), they obtained 26 amniotic fluid samples. They assessed the phenotype and number of amniotic fluid leukocytes via flow cytometry. They used immunoassays to ascertain amniotic fluid levels of classical pro-inflammatory cytokines, type 1 and type 2 cytokines, and T-cell chemokines. Compared with those with intra-amniotic inflammation, more severe cellular immune responses were seen in women with preterm labor and intra-amniotic infection. The principal immune cells reacting to microorganisms that invade the amniotic cavity were neutrophils, monocytes/macrophages, and CD4⁺ T cells.