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Increased serum concentration of immune cell derived microparticles in polymyositis/dermatomyositis
Zsuzsanna Baka1, Ladislav Senolt, Jiri Vencovsky
1Department of Genetics, Semmelweis University, Budapest, Hungary.
Abstract:
Microparticles are recently recognized players of intercellular communication. They are involved in signal transduction, cell activation and apoptosis. Their importance is also suggested in autoimmune diseases such as rheumatoid arthritis and systemic sclerosis. We investigated the role of microparticles in polymyositis/dermatomyositis, a group of rare autoimmune diseases, characterized by specific skin lesions and muscle weakness. The plasma concentration of monocyte and lymphocyte derived microparticles of 20 patients with polymyositis/dermatomyositis and 20 healthy controls were determined by flow cytometry. The structure of microparticles was visualized by electron microscopy. Significantly elevated numbers of monocyte (CD14 positive), T-lymphocyte (CD3 positive) and B-lymphocyte (CD19 positive) derived microparticles were found in the plasma samples of polymyositis/dermatomyositis patients, compared to healthy controls (p=0.001, 0.01 and 0.006, respectively). Furthermore, the plasma levels of monocyte and B-lymphocyte derived microparticles correlated with the manual muscle strength test (r=0.497, p=0.027; r=0.508, p=0.023; respectively). Patients with anti-Jo-1 antibody and lung involvement had significantly higher numbers of T- and B-lymphocyte and monocyte derived MPs (p=0.006, 0.012 and 0.007, respectively, for anti-Jo-1; p=0.013, 0.016 and 0.025, respectively, for lung involvement). After ultracentrifugation, CK activity could be detected only in traces in the resuspended pellet containing microparticles of healthy and diseased individuals. The electron microscopy revealed slightly different microparticles in the samples of patients with polymyositis/dermatomyositis. These results suggest that immune cell derived microparticles may contribute to the inflammatory process in polymyositis/dermatomyositis, however, CK-positive, possibly muscle derived microparticles do not seem to be present in the blood of patients with polymyositis/dermatomyositis.
Insights
Immune cell-derived microparticles are elevated in polymyositis/dermatomyositis patients, correlating with disease severity and specific antibodies. These microparticles may play a role in the inflammatory process of this autoimmune condition.
Area of Science:
- Immunology
- Cell Biology
- Autoimmune Diseases
Background:
- Microparticles are key mediators of intercellular communication, influencing cell signaling, activation, and apoptosis.
- Their role is increasingly implicated in autoimmune conditions like rheumatoid arthritis and systemic sclerosis.
- Polymyositis/dermatomyositis are rare autoimmune diseases characterized by muscle weakness and distinct skin manifestations.
Purpose of the Study:
- To investigate the role and levels of monocyte and lymphocyte-derived microparticles in polymyositis/dermatomyositis.
- To explore the correlation between microparticle levels and clinical parameters, including muscle strength and specific autoantibodies.
- To examine the structural characteristics and potential muscle origin of microparticles in patients.
Main Methods:
- Plasma samples from 20 polymyositis/dermatomyositis patients and 20 healthy controls were analyzed using flow cytometry.
- Monocyte (CD14+), T-lymphocyte (CD3+), and B-lymphocyte (CD19+) derived microparticles were quantified.
- Electron microscopy was employed to visualize microparticle structure, and creatine kinase (CK) activity was assessed.
Main Results:
- Significantly higher concentrations of monocyte, T-lymphocyte, and B-lymphocyte derived microparticles were observed in patients compared to controls (p<0.01).
- Plasma levels of monocyte and B-lymphocyte microparticles correlated with manual muscle strength (p<0.03).
- Elevated microparticle levels were associated with anti-Jo-1 antibody positivity and lung involvement (p<0.016).
Conclusions:
- Immune cell-derived microparticles are significantly elevated in polymyositis/dermatomyositis and may contribute to the disease's inflammatory processes.
- Microparticle levels correlate with disease severity markers, suggesting their potential as biomarkers.
- Muscle-derived microparticles (CK-positive) do not appear to be a significant component in the blood of these patients.
