Challenging Diagnosis: New Onset Antinuclear Antibody Negative Lupus Nephritis in a Pregnant Woman

A 30-year-old normotensive, pregnant woman (gravida one) was hospitalized because of acute renal failure (plasma creatinine, 1.2 mg/dL), marked proteinuria (7.94 g/day), and hematuria (30-50 red blood cells/high power field) at 31 weeks' gestation. She did not present with clinical manifestations typical of systemic lupus erythematosus (SLE), such as skin rash or arthritis. An antinuclear antibody (ANA) assay with Hep-2 cells as the substrate did not detect the presence of ANA and the plasma levels of complement components 3 and 4 were within normal limits. She received a cesarean section because of deterioration in renal function. A diagnosis of lupus nephritis, class IV, was made based on the results of renal biopsy and the presence of a high anti-double strand DNA antibody (anti-dsDNA) titer. The patient underwent a short course of hemodialysis therapy for refractory fluid overload and received treatment with steroids plus mycophenolate mofetil. She made a smooth recovery and was discharged with stable renal function.