MSFinals-5955
A 35-year-old woman presents with increasing early-morning bilateral knee pain and stiffness and generalised fatigue. On examination, she is noted to have flat erythema over the malar eminences with sparing of the nasolabial folds. Multiple painless oral ulcers are also noted. Examination of the knee joints reveals tenderness and suprapatellar effusions bilaterally.
Which of these is most specific for the underlying condition?