Q. A 31-year-old woman comes to the outpatient clinic because of bothersome joint pain. The patient delivered a preterm neonate 3 weeks ago. Her pregnancy was complicated with preeclampsia with severe hypertension requiring ICU admission and IV hydralazine. The patient's medical history is significant for polycystic ovarian syndrome. She describes herself as having been otherwise "healthy" throughout her life. Upon examination, the patient has no obvious joint deformity; however, arthralgias can be triggered by passive joint movement. An erythematous raised facial rash sparing the nasolabial folds is noted. Which of the following immunological biomarkers is likely elevated in the above patient?