Comparison of differentiated dendritic cell infiltration of autoimmune andosteoarthritis synovial tissue

Objective. Infiltration of rheumatoid arthritis (RA) synovial tissue (ST) b y differentiated dendritic cells (DC) is a consistent feature in patients w ith active disease. However, mononuclear cells (MNC), including DC, may be nonspecifically chemoattracted to inflammatory sites regardless of etiology , Therefore, to evaluate the specificity of ST infiltration by differentiat ed DC, synovial biopsies from patients with RA, spondylarthropathy (SpA), o steoarthritis (OA), and gout were examined. Methods. Formalin-fixed ST sections were analyzed by double immunohistochem ical staining for vascularity and infiltration by differentiated DC, lympho cytes, and macrophages. Results, DC containing nuclear RelB were found in perivascular MNC aggregat es from patients with all arthritides studied. Infiltration by differentiat ed DC was similar in RA and SpA ST, but reduced in OA ST. Differentiated DC were always observed in close association with lymphocytes, and the correl ation between these variables suggested that the infiltration of inflammato ry sites by DC and lymphocytes was associated. Conclusion, Perivascular infiltration by DC, lymphocytes, and macrophages i s nonspecifically related to inflammation, but signals present in RA and Sp A ST lead to more intense cellular infiltration and accumulation.