PROBLEM: To determine whether adenosine in amniotic fluid down-regulates pro-inflammatory cytokine production. METHOD OF STUDY: Mid-trimester amniotic fluid from 21 women was incubated ex vivo in the presence or absence of human adenosine deaminase, the enzyme that irreversibly degrades adenosine. After 24 hr, supernatants were assayed by ELISA for tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-6, and IL-10. Clinical parameters were obtained after completion of laboratory testing. RESULTS: Inclusion of adenosine deaminase resulted in a median increase in TNF-alpha production from 0.9 to 7.3 pg/mL (P = 0.0014). IL-6 production exhibited a non-significant median increase from <2.0 to 53.0 pg/mL (P = 0.0780). Median IL-10 production increased slightly from a median of <0.2 to 1.3 pg/mL. Adenosine deaminase-stimulated TNF-alpha production was proportional to parity and unrelated to gestational age, time of delivery, maternal age or indication for amniocentesis. CONCLUSION: Adenosine deaminase treatment increases TNF-alpha production by ex vivo-cultured amniotic fluid. Adenosine contributes to immune modulation in the amniotic cavity.
