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Increased expression of costimulatory molecules on peripheral blood monocytes in patients with Crohn's disease
Z X Liu1, N Hiwatashi, M Noguchi
1Third Dept. of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan.
Insights
In Crohn's disease (CD), activated T cells are increased. Monocytes in CD patients show higher expression of costimulatory molecules B7-2, CD18, and ICAM-1, potentially driving T-cell activation.
Area of Science:
- Immunology
- Gastroenterology
Background:
- Crohn's disease (CD) pathogenesis involves T lymphocyte and monocyte/macrophage activation.
- Costimulatory molecules are crucial for optimal T-cell activation.
Purpose of the Study:
- To investigate the expression of costimulatory molecules and activation markers on immune cells in Crohn's disease patients.
- To compare immune cell profiles between CD patients, ulcerative colitis (UC) patients, and healthy controls.
Main Methods:
- Flow cytometry was used to analyze peripheral blood monocytes and T lymphocytes.
- Expression of B7-1 (CD80), B7-2 (CD86), CD18, ICAM-1, HLA-DR, and IL-2R (CD25) was quantified.
Main Results:
- CD patients exhibited significantly increased activated T cells (HLA-DR+, IL-2R+) compared to controls and UC patients.
- Monocytes from CD patients showed significantly increased mean fluorescence intensity (MFI) for B7-2, CD18, and ICAM-1 compared to UC and controls.
- UC patients had lower monocyte HLA-DR expression (percentage and MFI) than CD patients and controls.
Conclusions:
- Peripheral blood monocytes in CD patients display elevated expression of B7-2, CD18, and ICAM-1.
- Increased expression of these costimulatory molecules on monocytes may correlate with T lymphocyte activation in CD.
Background:
Activation of T lymphocytes and monocytes/macrophages has been implicated in the pathogenesis of Crohn's disease (CD). Costimulatory molecules play important roles in optimal T-cell activation.
Methods:
With flow cytometric analysis we have investigated the expression of the costimulatory molecules B7-1 (CD80), B7-2 (CD86), and CD18 and the intercellular adhesion molecule-1 (ICAM-1) on peripheral blood monocytes and the expression of the activation markers HLA-DR and IL-2R (CD25) on peripheral blood T lymphocytes from 31 CD patients, 17 ulcerative colitis (UC) patients, and 10 healthy controls.
Results:
In CD patients the percentage of activated T cells (CD3+ HLA-DR+ and CD3+ IL-2R+) was significantly increased compared with those of controls and UC patients (P < 0.05). Most monocytes from all three groups expressed B7-2, CD18, and ICAM-1 molecules (all > 79%), but only a few positive cells expressed B7-1 molecules (< 5%). No significant differences were detected in the percentage positivity of all costimulatory molecules tested among CD, UC, and controls. The mean fluorescence intensity (MFI) of B7-1 in all three groups was very weak and not significantly different. However, in CD patients there was a significantly increased MFI of B7-2, CD18, and ICAM-1 molecules compared with UC and controls (P < 0.05). On the other hand, both the percentage positivity and MFI of HLA-DR molecules on monocytes of UC patients were significantly lower than those of CD patients and controls (P < 0.05).
Conclusions:
Expression of the costimulatory molecules B7-2, CD18, and ICAM-1 on peripheral blood monocytes of CD patients is increased. In CD patients activation of peripheral T lymphocytes may correlate with increased expression of these costimulatory molecules on peripheral blood monocytes.