Monocyte CD64 expression as a novel biomarker for the disease activity of systemic lupus erythematosus.

Objective: Interferon alpha (IFN-α) is a key cytokine associated with systemic lupus erythematosus (SLE). IFN-α induces the expression of CD64 on monocytes (mCD64). Although enhanced mCD64 expression has been reported in patients with SLE, it has never been assessed quantitatively.