Up-regulation of αEβ7, a novel integrin adhesion molecule, on T cells from systemic lupus erythematosus patients with specific epithelial involvement

Objective. To determine the possible role of a novel integrin, αEβ7, in the pathogenesis of systemic lupus erythematosus (SLE). Methods. Expression of αEβ7 was examined on peripheral blood lymphocytes (PBL) from normal subjects (n = 25) and patients with SLE (n = 31), primary Sjogren's syndrome (n = 7), or polymyositis/dermatomyositis (n = 8) by cytofluorometry and/or immunoprecipitation. Adhesion of αEβ7+ T cells to HSG epithelial cells was investigated using a confocal image analyzer. Results. After phytohemagglutinin stimulation, expression of αEβ7 on PBL, especially on CD8+ T cells, was significantly higher in SLE patients than in normal subjects (P < 0.01). Elevated αEβ7 expression was associated with the presence of oral ulcers or serositis (P < 0.05). Activated SLE T cells with enhanced αEβ7 expression strongly adhered to HSG; this adhesion was partially blocked by anti-αEβ7. Conclusion. Expression and adhesion of αEβ7 on activated PBL was significantly increased in patients with SLE with epithelial involvement. This suggests a role of this novel integrin in tissue-specific retention of activated PBL, due to increased αEβ7-E- cadherin interaction, which may contribute to epithelial inflammation.