Biomarkers in vasculitis.

PURPOSE OF REVIEW

Better biomarkers are needed for guiding management of patients with vasculitis. Large cohorts and technological advances had led to an increase in preclinical studies of potential biomarkers.

RECENT FINDINGS

The most interesting markers described recently include a gene expression signature in CD8+ T cells that predicts tendency to relapse or remain relapse-free in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, and a pair of urinary proteins that are elevated in Kawasaki disease but not other febrile illnesses. Both of these studies used 'omics' technologies to generate and then test hypotheses. More conventional hypothesis-based studies have indicated that the following circulating proteins have potential to improve upon clinically available tests: pentraxin-3 in giant cell arteritis and Takayasu's arteritis; von Willebrand factor antigen in childhood central nervous system vasculitis; eotaxin-3 and other markers related to eosinophils or Th2 immune responses in eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome); and matrix metalloproteinase-3, tissue inhibitor of metalloproteinase-1, and CXCL13 in ANCA-associated vasculitis.

SUMMARY

New markers testable in blood and urine have the potential to assist with diagnosis, staging, assessment of current disease activity, and prognosis. However, the standards for clinical usefulness, in particular, the demonstration of either very high sensitivity or very high specificity have yet to be met for clinically relevant outcomes.