Monocyte Gene Expression Signatures in Rheumatic Diseases: Biomarkers for Disease Activity and Tools for Diagnosis and Classification

Monocytes migrate through the blood to the peripheral tissues, where they can develop into dendritic cells (DC) and macrophages. Studies on the phenotype of peripheral blood monocytes in rheumatic diseases revealed changes in the number of CD16+ monocytes and in the adhesive, chemotactic, antigen presenting and inflammatory properties of the cells. However, these studies often resulted in fragmented and inconsistent data and are hampered by the heterogeneity and overlap of the rheumatic diseases.