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Immunocytologic characteristics of mononuclear cell populations found in nonseptic olecranon bursitis
D L Smith1, A C Bakke, S M Campbell
1Department of Medicine, Veterans Affairs Medical Center, Portland.
Insights
Nonseptic olecranon bursitis involves activated T cells and monocyte/macrophages. These immune cells may play a role in the development and ongoing inflammation of bursitis.
Area of Science:
- Immunology
- Cell Biology
- Rheumatology
Background:
- Olecranon bursitis is a common condition, often presenting without infection.
- Understanding the cellular mechanisms is crucial for effective treatment strategies.
Purpose of the Study:
- To characterize the immunocytologic profile of mononuclear cells in nonseptic olecranon bursal fluid.
- To investigate the subtypes and activation status of lymphocytes and monocyte/macrophages.
Main Methods:
- Analysis of bursal fluid from 20 patients with culture-negative olecranon bursitis.
- Utilized immunocytochemistry and flow cytometry with monoclonal antibodies.
- Assessed lymphocyte (T cells, B cells) and monocyte/macrophage populations and their activation markers.
Main Results:
- Both traumatic and idiopathic bursitis showed elevated proportions of activated T lymphocytes (CD2+, CD25+, CD26+, HLA-DR+) and monocyte/macrophages (CD14+, HLA-DR+).
- T cell subsets (CD4/CD8 ratio) differed between traumatic and idiopathic cases.
- Monocyte/macrophages constituted a significant portion of mononuclear cells, with high HLA-DR expression indicating activation.
Conclusions:
- Nonseptic olecranon bursitis is associated with a predominance of activated T cell subpopulations and monocyte/macrophages.
- These findings suggest an immunologic component in the pathogenesis and persistence of nonseptic bursitis.
Objective:
To determine the immunocytologic characteristics of the various subsets of nonseptic olecranon bursal fluid mononuclear cells.
Methods:
Twenty consecutive patients with culture negative olecranon bursitis had immunocytochemical and flow cytometric analysis performed using a panel of monoclonal antibodies to determine lymphocyte and monocyte/macrophage population subtypes and proportions.
Results:
In traumatic bursitis (n = 9), the mean (+/- SD) white blood cell (WBC) count/mm3 was 1,368 +/- 1,559; WBC mononuclear differential count was 29.5 +/- 19% lymphocytes and 55 +/- 26% monocyte/macrophages. In idiopathic bursitis (n = 11), the mean WBC/mm3 was 376 +/- 515; WBC mononuclear differential count was 28.5 +/- 16% lymphocytes and 52 +/- 27% monocytes/macrophages. Flow cytometry revealed 88% CD2+ T lymphocytes in the lymphocyte population, 3% B lymphocytes and CD4/CD8 T cell mean ratio of 2.5 +/- 1.5 for traumatic bursitis and 88% CD2+ T lymphocytes, 4% B lymphocytes and CD4/Cd8 ratio of 1.4 +/- 0.6 for idiopathic bursitis (p < 0.05, t test). Both groups contained increased proportions of lymphocyte subtypes expressing activation markers: CD25+, CD26+ and HLA DR+ compared to normal peripheral blood. In traumatic bursitis, the mean percent of CD14+ cells (monocyte/macrophages) was 62 +/- 24; in idiopathic bursitis, the mean percent was 51 +/- 28. The vast majority expressed high levels of HLA-DR indicating activation.
Conclusion:
We observed a preponderance of activated T cell subpopulations and monocyte/macrophages suggesting an immunologic role for these cell populations in the development and perpetuation of nonseptic bursitis.