Background: Dendritic cells (DCs) are potent antigen-presenting cells (APC) that are deeply implicated in the initiation and exacerbation of rheumatoid arthritis (RA). Active RA is associated with an activated DCs population as demonstrated by high expression of adhesion and co-stimulatory molecules.
Purpose: To compare the expression of adhesion and co-stimulatory molecules on DCs from synovial tissue (ST) in patients (pts) with RA and the clinical status before and after treatment with disease modifying antirheumatic drugs (DMARDs).
Methods: Samples of ST were obtained from RA patients at the time of hip or knee replacement or arthroscopy. Clinical status (assessed by the American College of Rheumatology - ACR - core set and the DAS28) and co-stimulatory and adhesion molecules on DCs were evaluated before and after treatment. Immunophenotype of DCs was analyzed by two-color immunofluorescence microscopy.
Results: In patients with active RA we found a highly differentiated subpopulation of DCs that expressed an activated phenotype. After treatment, the expression of adhesion and co-stimulatory molecules on ST DCs was correlated with the ACR and DAS28 clinical response.
Conclusion: Clinical outcome and the immunophenotypical presentation of ST DCs after DMARDs treatment are closely correlated in pts with RA. The co-stimulatory activity in the synovium is important in determining the course of the disease and provide new therapeutic targets for immune intervention.