Update on ANCA-associated vasculitis: from biomarkers to therapy.

ANCA-associated vasculitis (AAV) are the prototype of a disease characterised by the presence of a biomarker; ANCA positivity in fact is recorded in 90% of cases of GPA and MPA. The role of ANCA in the management of AAV ranges from diagnostic to prognostic purposes with also therapeutic implications. Changes in clinical practice with the increased use of rituximab have drawn attention to B-cells as a biomarker able to contribute to patient management. Cytokines and other circulating factors, although still at a research stage, may represent future biomarkers of interest or even therapeutic options. From the point of view of renal involvement in AAV, proteinuria and microhematuria are still the biomarkers employed in everyday clinical practice with a proposed role for emerging ones (MCP1, CD163 and CD25). The aim of this review is to discuss the role of well-known biomarkers in everyday clinical management of AAV patients as well as future perspectives for those that are still at a research stage with attention to therapeutic implications.