Objective: To determine the levels and isotypes of aCl, as well as anti beta 2 glycoprotein 1 (antiβ2-GP1) antibodies in serum and amniotic fluid of pregnant patients with SLE and/or APLS, and healthy pregnant women serving as a control group. Material and Methods: We analyzed serum and amniotic fluid of pregnant patients with SLE and/or APLS, and of healthy pregnant women through ELISA. Results were compared using a Student's T test. Results: 6 of 13 patients (46.1%), 5 with SLE and one with

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... imary APLS had antiphospholipid antibodies in amniotic fluid. Two patients had IgG aCl and 4 patients had antiβ2-GP1 (one of them also showing IgM) in amniotic fluid. In serum, 4 patients (30%) had antiphospholipid antibodies present (one IgG aCl and three anti β2-GP1) as opposed to none in the control group having antiphospholipid antibodies in amniotic fluid. Only one control had IgM aCl in serum. Antiβ2-GP1 in the amniotic fluid of patients showed a statistically significant value when compared to controls. Conclusion: aCl and antiβ2-GP1 may be present in the amniotic fluid of patients with and without a history of fetal loss. The presence of