Chorioamnionitis and inflammation of the fetal lung

OBJECTIVE: Fetal intrauterine exposure to proinflammatory cytokines present In amniotic fluid has been associated with an increased risk of chronic lu ng disease, However, the impact of histologically confirmed chorioamnioniti s, on the fetal lung has not yet been elucidated. We therefore Investigated cellular immune response, cell proliferation, and messenger ribonucleic ac id cytokine expression in fetal pulmonary tissue in the presence or absence of chorioamnionitis. STUDY DESIGN: Serial tissue sections were obtained from 27 fetuses at the t ime of autopsy. Three mothers had received antibiotics for treatment of cli nical chorioamnionitis before abortion. Immunohistochemical staining of lun g tissue comprised lineage-specific markers (CD68(+), CD3(+), neutrophil el astase). Positively stained cells were evaluated with a graticule, and cell s per 5 mm(2) were counted. We undertook in situ hybridization to assess th e expression of interleukin 8 messenger ribonucleic acid in the fetal lung. RESULTS: Seven of 27 fetuses had been exposed to chorioamnionitis. Fetal lu ngs showed a marked increase in the presence of histologically confirmed ch orioamnionitis in densities of CD68(+) macrophages (68 vs 9.5 cells/5 mm(2) , median group vs control group; P = .02) and lymphocytes (7 vs 2.5 Cells/5 mm(2), median chorioamnionitis vs control group; P = .05) and a similar bu t lesser increase In neutrophil density (16 vs 4 cells/5 mm(2); difference not significant). Interleukin 8 messenger ribonucleic acid was expressed in 4 of 6 tissue specimens investigated In the chorioamnionitis group. Exposu re to chorioamnionitis resulted in interleukin 8 messenger ribonucleic acid expression 7-fold higher than In the nonchorioamnionitis group; however, t his difference did not achieve statistical significance. CONCLUSION: Chorioamnionitis was associated with an intrauterine inflammato ry response of the fetal lung characterized by a severe infiltration of mac rophages, neutrophits, and lymphocytes and also by an increased expression of interleukin 8 messenger ribonucleic acid.