Early Human Development, 10 (1985) 219-286 Elsevier 219 EHD 00613 Identification of viral infections in pregnancy by assay of (2’-5’) -oligo-isoadenylate synthetase Alex Schoenfeld ‘, Jardena Ovadia ‘, Chanoch Levavi ‘, Shmuel Nitke ‘, David Wallach *, Amichai Schattner * and Michel Revel 2 ’ Department of Obstetrics and Gynecology, Be&son Medical Center, Tel Aviv University Sackler School of Medicine, Tel Aviv; and’ Department of Virology, Weizmann Institute of Science, Rehovot, Israel Accepted for publication 3 August 1984 Summary Interferons are produced in response to viral infections. Among the biochemical changes they cause in cells is the induction of the enzyme (2’-5’)-oligo-isodenylate synthetase. The activity of this enzyme can be measured and this can indicate exposure and response of cells to interferon. The efficacy of such an assay of peripheral blood of pregnant women may aid in establishing screening guidelines for potentially teratogenic viral infections. The blood of 44 primigravidas with complaints of fever, myalgia, cough, vaginal discharge and/or costovertebral angle tenderness was assayed for activity of the enzyme (2’-5’)-oligo-isoadenylate synthetase and compared to assays of the enzyme activity in a group of 37 healthy primigravidas which served as a control group. It was found that the group with viral infections had an increase in enzyme activity from twice to 15 times the normal value, with characteristic rises of enzyme activity in several viruses known or suspected to cause human defects. Several general guidelines are proposed to assist the obstetrician in determining a viral etiology of acute illness in pregnancy, It is suggested that the assay of enzyme activity of (2’-5’)-oligo-isoadenylate synthetase may provide a simple tool for rapid diagnosis of viral infections in pregnancy. (2’-5’)-oligo-isoadenylate synthetase; viral infections; teratology; interferon Address for correspondence: Dr. Alex Schoenfeld, Department of Obstetrics and Gynecology, Beilinson Medical Center, Petah Tiqva 49100, Israel. 037%3782/85/$03.30 0 1985 Elsevier Science Publishers B.V. (Biomedical Division)