Increase in the expression of alpha E beta 7, characteristic of intestinal intraepithelial lymphocytes, on T cells in the lung epithelium of patients with interstitial lung diseases and in synovial fluid of patients with rheumatic diseases.
The intestinal epithelium contains a distinct group of lymphocytes (iIEL). The majority of iIEL are T cells characterized by a phenotype different from PBL. This phenotypic peculiarity has led to the hypothesis that iIEL, develop in a thymus-independent fashion, that they may develop locally in the gut epithelium itself and that they have the distinct function of providing a first line of defense in the gut. We looked at the expression of the gut-associated surface molecule alpha E beta 7 on T cells in inflamed tissues outside the gut epithelium. The already high frequency of 41.8% alpha E beta 7+ T cells in bronchoalveolar lavage from healthy lungs rises to a median of 61% in a fibrotic lung. In synovial fluid the percentage of T cells expressing alpha E beta 7 was diverse; it was not as high as in the lung but was elevated compared to PBL levels. In both tissues, the increase in alpha E beta 7 expression correlated with an increase in CD8+ cells. We discuss our data in the context of a model in which iIEL can leave the gut epithelium and become involved in inflammatory processes, possibly related to autoimmune disease.
Baumgart
M
M
Deutsches Rheuma-Forschungszentrum Berlin, Germany.
Witt
C
C
Hüge
W
W
Müller
B
B
D001172:Arthritis, Rheumatoid / Q000276:immunology / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000032:analysis / Q000096:biosynthesis; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D004848:Epithelium / Q000276:immunology / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D016023:Integrins / Q000032:analysis* / Q000096:biosynthesis*; D008168:Lung / Q000378:metabolism*; D017563:Lung Diseases, Interstitial / Q000276:immunology / Q000378:metabolism*; D010581:Peyer's Patches / Q000378:metabolism*; D013582:Synovial Fluid / Q000276:immunology*; D013601:T-Lymphocytes / Q000378:metabolism*
D014408:Biomarkers, Tumor; D016023:Integrins; C070709:integrin alphaEbeta7