CSF1 and anti-neutrophil cytoplasmic antibody-associated vasculitis: Recently, increased serum M-CSF levels have been associated with active vasculitis in humans and have been proposed as a biomarker of renal involvement of AAV, as well as serum and urine CSF-1 levels correlated with lupus activity and can potentially act as lupus biomarkers and predict the onset and recurrence of LN.