Relationship Between Adenosine Deaminase Activity and CytokineSecreting T Cells in Normal Pregnancy

Yoneyama, Yoshio MD; Sawa, Rintaro MD; Suzuki, Shunji MD; Yoneyama, Koichi MD; Doi, Daisuke MD; Araki, Tsutomu MD

Original Research

OBJECTIVE: To evaluate the relationship between plasma adenosine deaminase activity and the proportion of cytokine‐secreting T cells as causes of changes in adenosine deaminase activity in normal pregnancy.

METHODS: Plasma adenosine deaminase activity and the proportions of cytokine‐secreting T cells were measured in the peripheral blood of 26 nonpregnant and normal pregnant women in the third trimester. The proportion of CD4‐positive T cells secreting interferon‐γ derived from T helper 1 cells, and interleukin‐4 derived from T helper 2 cells, were analyzed by flow cytometry. The ratio of interferon‐γ–secreting cells to interleukin‐4–secreting cells was taken as the T helper 1/T helper 2 ratio.

RESULTS: Mean plasma adenosine deaminase activity in normal pregnant women, averaged, was significantly lower than that in nonpregnant women (10.3 ± 0.6 U/L versus 13.8 ± 0.5 U/L, P < .05). In normal pregnant women, the proportion of interferon‐γ–secreting cells was significantly lower than that in nonpregnant women (20.5% ± 1.0% versus 24.7% ± 1.2%, P < .05), but the proportion of interleukin‐4–secreting cells did not differ from that of nonpregnant women. Consequently, the T helper 1/T helper 2 ratios were significantly decreased during normal pregnancy. A significant correlation was found between adenosine deaminase activity and the proportion of interferon‐γ–secreting cells (r = .54, P < .05).

CONCLUSION: Decreased plasma adenosine deaminase activity in normal pregnant women may be in part associated with changes in the immunological status, especially the decrease of the proportion of interferon‐γ–secreting cells.

Decreased plasma activity of adenosine deaminase may be in part associated with the decrease in the proportion of interferon‐g–secreting cells during normal pregnancy.

Department of Obstetrics and Gynecology, Nippon Medical School, Tokyo, Japan.

Address reprint requests to: Yoshio Yoneyama, MD, Nippon Medical School, Department of Obstetrics and Gynecology, 1–1‐5, Sendagi, Bunkyo‐ku, Tokyo, 113–8603, Japan; E‐mail: yoshi‐1@nms.ac.jp.

Supported by a Grant‐in‐Aid (No. 12470349) from the Ministry of Education, Culture, Sports, Science and Technology.

Received January 30, 2002. Received in revised form April 11, 2002. Accepted May 2, 2002.

© 2002 by The American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved.