A 32-year-old woman presents with a 3-year history of hair loss during combing and recurrent painless oral ulcers. For the past 2 years, she has experienced finger pallor, pain, and subsequent cyanosis upon cold exposure in winter, which later resolves. During history-taking, the physician notes that the patient develops facial skin erythema after sun exposure in summer, raising suspicion of SLE. Which of the following lab findings indicates active lupus?