Air pollution and distributions of lymphocyte immunophenotypes in cord and maternal blood at delivery.

A cross-sectional study of deliveries in two districts in the Czech Republic, 1994-1996, assessed the relation between air pollution and lymphocyte immunophenotype distributions. Maternal and cord blood samples were assayed by flow cytometry within 24 hours of delivery for 303 deliveries from Teplice, a polluted district, and 215 from Prachatice, a less polluted district. Analyses focused on: CD3(+) T-lymphocytes, CD3(-) CD19(+) B-lymphocytes, and CD3(-) CD16(+)56(+) natural killer (NK) lymphocytes, as well as the subsets CD3(+)CD4(+) ("T-helper") and CD3(+)CD8(+) ("T cytotoxic/suppressor") and the ratio of these two lymphocytes. We collected reproductive, occupational, and life-style information by questionnaire, and abstracted data on labor and delivery from medical records. After adjustment for numerous risk factors in multivariate linear regression models fit for each lymphocyte subset, mothers from Teplice had lower percentages of total T-cells and of CD4(+) cells, and a lower ratio of CD4(+):CD8(+) cells. Cord bloods from Teplice had a higher percentage of NK cells and a less precise lower percentage of T-cells. Stronger differences in maternal lymphocytes were seen when analyses were limited to the central hospital in each district. Heavy air pollution may affect the immune system in pregnant women and/or fetuses, reflecting an acute and/or chronic effect, although unmeasured confounders could also play a role.