Article
Total monocytes and intermediate and non-classical monocyte subpopulation are expanded in patients with systemic sclerosis
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Authors
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Kathleen Friedrich
- Universität Leipzig, Rheumatologie, Leipzig
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Ulf Wagner
- Universitätsklinikum Leipzig, Klinik und Poliklinik für Gastroenterologie und Rheumatologie, Sektion Rheumatologie, Leipzig
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Christoph G. O. Baerwald
- Universitätsklinikum Leipzig, Klinik und Poliklinik für Gastroenterologie und Rheumatologie, Sektion Rheumatologie, Leipzig
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Matthias Pierer
- Universitätsklinikum Leipzig, Klinik und Poliklinik für Gastroenterologie und Rheumatologie, Sektion Rheumatologie, Leipzig
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Manuela Rossol
- Universitätsklinikum Leipzig, Klinik und Poliklinik für Gastroenterologie und Rheumatologie, Sektion Rheumatologie, Leipzig
| Published: | February 5, 2019 |
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Outline
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Background: Many studies suggest that circulating monocytes are actively involved in the autoimmune disease systemic sclerosis (SSc). Circulating CD14+ monocytes form a heterogeneous population and can be differentiated into classical, intermediate and non-classical monocytes, and in addition, the CD56+ monocyte subpopulation is part of the classical monocytes. Monocyte subpopulations are expanded in many autoimmune diseases and the aim of the study was to determine the monocyte subpopulations in patients with SSc.
Methods: The frequencies of monocyte subpopulations in the peripheral blood of age-matched healthy donors (n=17) and patients with SSc (n=29) were analyzed by flow cytometry. The cells were stained with anti-CD14, anti-CD16 and anti-CD56 antibodies. The absolute monocyte count was determined in the clinic and the absolute monocyte subpopulation numbers were calculated using the frequency and the absolute monocyte count.
Results: The absolute number of circulating CD14+ monocytes was significantly increased in patients with SSc compared to healthy controls (713/µl ± 50 vs. 479/µl ± 30, p=0.001). The frequencies of intermediate monocytes (9.7% ± 0.7 vs. 5.9 ± 0.7, p<0.001) and non-classical monocytes (14.3% ± 1.7 vs. 8.5% ± 1.3, p=0.023) were increased while the frequency of classical monocytes was decreased (72.1% ± 2.4 vs. 83.0% ± 2.1, p=0.004) in SSc patients compared to controls. Calculated absolute monocyte subpopulation numbers revealed that intermediate monocytes (73/µl ± 11 vs. 31/µl ± 5, p<0.0001) and non-classical monocytes (92/µl ± 11 vs. 43/µl ± 8, p<0.001) are truly expanded in SSc patients compared to controls while there is no difference between classical monocytes of SSc patients and controls (523/µl ± 47 vs. 426 ± 32, ns). The frequency of CD56+ monocytes was decreased in SSc patients compared to healthy individuals (12.4% ± 1.9 vs. 16.7% ± 1.9, p<0.01) but calculated absolute CD56+ monocyte numbers were not different (97/µl ± 20 vs. 85/µl ± 11, ns).
Conclusion: Total monocytes and the intermediate and non-classical monocyte subpopulations are expanded in patients with SSc indicate a possible contribution of these cells to the pathogenic process of SSc.
