RANTES expression and contribution to monocyte chemotaxis in arthritis

Area of Science:

• Immunology
• Rheumatology
• Cell Biology

Background:

• Rheumatoid arthritis (RA) involves leukocyte infiltration into synovial tissue and fluid, driven by chemotactic signals.
• RANTES is a significant chemoattractant for leukocytes, including monocytes and T lymphocytes.

Purpose of the Study:

• To investigate the production, cellular source, and functional role of antigenic RANTES in arthritis.
• To determine if RANTES contributes to the chemotactic activity observed in the joints of RA and OA patients.

Main Methods:

• Quantification of antigenic RANTES in synovial fluid (SF) from RA and osteoarthritis (OA) patients.
• Stimulation of synovial tissue (ST) fibroblasts and SF mononuclear cells to assess RANTES production.
• Immunolocalization of antigenic RANTES in RA and OA synovial tissue.
• Assessment of anti-RANTES antibody's effect on monocyte chemotaxis in RA SF.

Main Results:

• Antigenic RANTES was detected in SF from both RA and OA patients.
• Interleukin-1beta and tumor necrosis factor-alpha significantly increased RANTES production by RA ST fibroblasts.
• RA SF mononuclear cells showed increased RANTES secretion upon stimulation with PHA and LPS.
• Immunolocalization revealed RANTES in macrophages and synovial lining cells in RA and OA tissues.
• Anti-RANTES antibody partially neutralized the chemotactic activity of RA SF for monocytes.

Conclusions:

• Antigenic RANTES is present in the synovial tissue and fluid of RA and OA patients.
• RANTES is produced by synovial fibroblasts and mononuclear cells in response to inflammatory stimuli.
• RANTES acts as a chemoattractant for monocytes within the inflamed RA joint, contributing to leukocyte recruitment.