Increased expression of costimulatory molecules on peripheral blood monocytes in patients with Crohn's disease.
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.
Liu
Z X
ZX
Third Dept. of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan.
Hiwatashi
N
N
Noguchi
M
M
Toyota
T
T
D000293:Adolescent; D000328:Adult; D015703:Antigens, CD / Q000378:metabolism; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism*; D018122:B7-1 Antigen / Q000378:metabolism; D051940:B7-2 Antigen; D018821:CD18 Antigens / Q000378:metabolism; D003093:Colitis, Ulcerative / Q000378:metabolism; D003424:Crohn Disease / Q000378:metabolism*; D005260:Female; D005434:Flow Cytometry; D019085:Fluorescent Antibody Technique, Direct; D006684:HLA-DR Antigens / Q000378:metabolism; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D008875:Middle Aged; D009000:Monocytes / Q000378:metabolism*; D015375:Receptors, Interleukin-2 / Q000378:metabolism; D013601:T-Lymphocytes / Q000378:metabolism*
D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D018122:B7-1 Antigen; D051940:B7-2 Antigen; D018821:CD18 Antigens; C497964:CD86 protein, human; D006684:HLA-DR Antigens; D008562:Membrane Glycoproteins; D015375:Receptors, Interleukin-2; D018799:Intercellular Adhesion Molecule-1