Subcellular particles in synovial fluids and synovial cells

Area of Science:

• Rheumatology
• Virology
• Microbiology

Background:

• Rheumatoid arthritis (RA), osteoarthrosis (OA), and psoriatic arthritis (PA) are common joint diseases.
• The etiology of these conditions, particularly RA, is not fully understood.
• Synovial fluid analysis can provide insights into the pathological processes of arthritis.

Purpose of the Study:

• To investigate the presence and types of microscopic particles in synovial fluid from patients with RA, OA, and PA.
• To compare the incidence of these particles across different arthritis types.
• To explore the potential etiological significance of observed particles, especially viral-like ones, in RA.

Main Methods:

• Negative staining and electron microscopy were used to examine synovial fluid pellets.
• Samples were obtained from patients diagnosed with RA, OA, and PA.
• Cultured rheumatoid synovial macrophage syncytia were analyzed using ultra-thin section electron microscopy.

Main Results:

• Membranous (mycoplasma-like) and non-membranous (viral-like) particles were detected in synovial fluids.
• Incidence of membranous particles: RA (22/28), OA (7/11), PA (1/3).
• Incidence of non-membranous particles: RA (12/28), OA (1/11), PA (1/3).
• Higher frequency of viral-like particles observed in RA synovial fluids compared to OA and PA.
• Viral-like particles were also found within the nuclei of cultured rheumatoid synovial macrophages.

Conclusions:

• The study identified both mycoplasma-like and viral-like particles in the synovial fluid of arthritis patients.
• A significantly higher prevalence of viral-like particles was noted in rheumatoid arthritis patients.
• These findings suggest a potential etiological role for viral-like particles in rheumatoid arthritis pathogenesis.