Relation between adenosine and T-helper 1/T-helper 2 imbalance in women with preeclampsia

OBJECTIVE: To evaluate the relationship between changes in plasma adenosine concentration and imbalances in the T-helper 1/T-helper 2 ratio in peripheral blood of women with preeclampsia. METHODS: Plasma adenosine concentrations and the T-helper 1/T-helper 2 ratio were examined in the peripheral blood of 16 preeclamptic and normal pregnant women. The proportion of specific T-cell marker CD4-positive cells expressing intracellular cytokines, interferon-gamma derived from T-helper 1 and interleukin-4 derived from T-helper 2 cells, were analyzed by flow cytometry. The ratio of interferon-gamma secreting cells to interleukin-4 secreting cells was taken as the T-helper 1/T-helper 2 ratio in vivo. The effect of the adenosine-receptor blocker 8-sulfophenyltheophylline was also measured in vitro. RESULTS: Mean plasma adenosine concentration in preeclampsia was significantly higher than that in normal pregnancy (0.68 +/- 0.07 mumol/L versus 0.39 +/- 0.06 mumol/L, P < .05). The proportions of interferon-gamma secreting cells increased and interleukin-4 secreting cells decreased significantly in preeclampsia, and the T-helper 1/T-helper 2 ratio in preeclampsia was significantly higher than in normal pregnancy (18.1 +/- 2.6 versus 9.9 +/- 1.5, P < .05). The increase of the proportion of interferon-gamma secreting cells after adenosine receptor blockade in preeclampsia significantly exceeded that of normal pregnancy. The T-helper 1/T-helper 2 ratio in preeclampsia was significantly greater than that in normal pregnancy (36% versus 17%, P < .05). CONCLUSION: Increased plasma adenosine may be involved in the regulation of imbalances in the T-helper 1/T-helper 2 ratio in women with preeclampsia. (Obstet Gynecol 2002;99:641-6. (C) 2002 by the American College of Obstetricians and Gynecologists.).