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Updated: May 20, 2026
Measuring Erythrocyte Complement Receptor 1 Using Flow Cytometry
Published on: May 19, 2020
Diminished expression of complement regulatory proteins on peripheral blood cells from systemic lupus erythematosus
Ana Paula Alegretti1, Laiana Schneider, Amanda Kirchner Piccoli
1Serviço de Patologia Clínica, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2350, 2° Andar, 90035-903 Porto Alegre, RS, Brazil. anaalegretti@gmail.com
Insights
Complement regulatory proteins (Creg) like CD55, CD59, CD46, and CD35 are altered in systemic lupus erythematosus (SLE) patients. Reduced Creg expression on blood cells correlates with cytopenia and disease activity in SLE.
Area of Science:
- Immunology
- Hematology
- Complement System Biology
Background:
- Complement regulatory proteins (Creg), including CD55, CD59, CD46, and CD35, are crucial for maintaining cell and tissue integrity during complement system activation.
- Dysregulation of the complement system is implicated in the pathogenesis of systemic lupus erythematosus (SLE).
Purpose of the Study:
- To investigate the expression levels of key Creg proteins on peripheral blood cells in patients with SLE.
- To determine the association between Creg expression and the presence of cytopenia (low blood cell counts) and overall disease activity in SLE patients.
Main Methods:
- Flow cytometry was utilized to analyze the expression of CD55, CD59, CD46, and CD35 on peripheral blood cells.
- The study included 100 SLE patients and 61 healthy controls.
Main Results:
- SLE patients exhibited decreased expression of CD55, CD59, and CD46 on leukocytes in the presence of lymphopenia and neutropenia compared to healthy controls.
- Anemia in SLE patients was associated with reduced CD59 and CD35 expression on red blood cells.
- A negative correlation was observed between CD55 and CD59 expression on neutrophils and SLE disease activity scores.
Conclusions:
- Peripheral blood cells in SLE patients display an altered pattern of complement regulatory protein expression.
- The observed changes in Creg expression are linked to cytopenia and disease activity, suggesting a role in SLE pathogenesis and complement system activation.
Abstract:
CD55, CD59, CD46, and CD35 are proteins with complement regulatory (Creg) properties that ensure cell and tissue integrity when this system is activated. The aim of this study was to evaluate the Creg expression on peripheral blood cells from SLE patients and its association with cytopenia and disease activity. Flow cytometric analyses were performed on blood cells from 100 SLE patients and 61 healthy controls. Compared with healthy controls, we observed in SLE patients with lymphopenia and neutropenia decreased expression of CD55, CD59, and CD46 (P < 0.05). In SLE patients with anemia, CD59 and CD35 were decreased on red blood cells. Furthermore, there was a negative correlation between CD55 and CD59 on neutrophils and the disease activity. The results suggest there is an altered pattern of Creg expression on the peripheral blood cells of SLE patients, and the expression is correlated with disease activity and/or with activation of the complement system.
