Soluble Flt-1, Placental Growth Factor, and Vascular Endothelial Growth Factor Serum Levels to Differentiate Between Active Lupus Nephritis During Pregnancy and Preeclampsia

Objective To evaluate mean serum levels of vascular endothelial growth factor (VEGF), placental growth factor (PlGF), and soluble Flt-1 (sFlt-1) in pregnant patients with systemic lupus erythematosus (SLE) with inactive disease, active lupus nephritis, and preeclampsia for differential diagnosis between these conditions. Methods Pregnant women with SLE, with singleton pregnancies and no other autoimmune diseases, were classified according to disease activity (inactive SLE and active lupus nephritis) and the presence of preeclampsia. Serum samples were collected within 3 weeks of delivery and frozen for subsequent blinded analysis through the enzyme-linked immunosorbent assay method. Results A total of 71 women were included, with 41 classified as having inactive SLE (group 1; Systemic Lupus Erythematosus Pregnancy Disease Activity Index [SLEPDAI] score <4), 15 with a diagnosis of active lupus nephritis (group 2, SLEPDAI score >= 4, including renal criteria), and 15 with a diagnosis of preeclampsia (group 3). Patients in group 3 had higher mean levels of sFlt-1 and lower mean levels of PlGF compared to groups 1 and 2, both findings with statistical significance. The sFlt-1:PlGF ratio was also significantly higher in patients with preeclampsia, while mean VEGF levels were higher in pregnant woman with active lupus nephritis compared to patients with preeclampsia or inactive SLE. Conclusion Evaluation of serum VEGF, PlGF, and sFlt-1 levels can differentiate between preeclampsia, inactive SLE, and active lupus nephritis during pregnancy.