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Polymorphonuclear functions in patients with mixed connective tissue disease
E Bodolay1, K Lukács, G Frendl
13rd Department of Medicine, University Medical School of Debrecen, Hungary.
Abstract:
Polymorphonuclear leukocytes (PMNs) from 29 patients with mixed connective tissue disease (MCTD) were studied "in vitro" for their phagocytic and chemotactic function as well as for granulocyte alkaline phosphatase (GAP) activity. Fc-receptor expression detected by EA-rosette formation was comparable to the control. Yeast-phagocytosis, C3b-receptor mediated phagocytosis and chemotaxis of PMNs, however, significantly decreased in MCTD. At the same time, photometric measure of alkaline phosphatase activity indicated a nearly two fold increase in PMNs from patients with MCTD. Although no correlation was found between PMN functions and the activity of the disease, PMN disorders may play a role in pathogenesis of these connective tissue disorders.
Insights
Polymorphonuclear leukocytes (PMNs) from mixed connective tissue disease (MCTD) patients show impaired phagocytosis and chemotaxis. Granulocyte alkaline phosphatase activity was significantly increased, suggesting PMN dysfunction in MCTD pathogenesis.
Area of Science:
- Immunology
- Rheumatology
- Cell Biology
Background:
- Mixed connective tissue disease (MCTD) is an autoimmune disorder with overlapping features of systemic lupus erythematosus, scleroderma, and polymyositis.
- Polymorphonuclear leukocytes (PMNs) are crucial immune cells involved in host defense and inflammation.
- Dysfunction of PMNs may contribute to the pathogenesis of autoimmune and connective tissue diseases.
Purpose of the Study:
- To investigate the in vitro phagocytic and chemotactic functions of PMNs in patients with MCTD.
- To assess the activity of granulocyte alkaline phosphatase (GAP) in PMNs from MCTD patients.
- To explore the potential role of PMN disorders in the pathogenesis of MCTD.
Main Methods:
- Isolation and in vitro study of PMNs from 29 patients with MCTD and healthy controls.
- Assessment of Fc-receptor expression using EA-rosette formation.
- Evaluation of yeast-phagocytosis and C3b-receptor mediated phagocytosis.
- Measurement of PMN chemotaxis.
- Photometric determination of granulocyte alkaline phosphatase (GAP) activity.
Main Results:
- Fc-receptor expression on PMNs was comparable between MCTD patients and controls.
- Yeast-phagocytosis, C3b-receptor mediated phagocytosis, and chemotaxis of PMNs were significantly reduced in MCTD patients.
- PMNs from MCTD patients exhibited a nearly two-fold increase in alkaline phosphatase activity compared to controls.
- No significant correlation was found between PMN functions and disease activity in MCTD.
Conclusions:
- PMNs from MCTD patients display functional deficits in phagocytosis and chemotaxis.
- Elevated GAP activity in PMNs suggests an altered metabolic state in MCTD.
- These PMN abnormalities may contribute to the pathogenesis of mixed connective tissue disease.