['Transforming growth factor (TGF)-beta has a central role in driving many of the pathological processes that characterize pulmonary fibrosis. Inhibition of the integrin alpha(v)beta6, a key activator of TGF-beta in lung, is an attractive therapeutic strategy, as it may be possible to inhibit TGF-beta at sites of alpha(v)beta6 up-regulation without affecting other homeostatic roles of TGF-beta.', 'To analyze the expression of alpha(v)beta6 in human pulmonary fibrosis, and to functionally test the efficacy of therapeutic inhibition of alpha(v)beta6-mediated TGF-beta activation in murine bleomycin-induced pulmonary fibrosis.', 'Lung biopsies from patients with a diagnosis of systemic sclerosis or idiopathic pulmonary fibrosis were stained for alpha(v)beta6 expression. A range of concentrations of a monoclonal antibody that blocks alpha(v)beta6-mediated TGF-beta activation was evaluated in murine bleomycin-induced lung fibrosis.', 'Alpha(v)beta6 is overexpressed in human lung fibrosis within pneumocytes lining the alveolar ducts and alveoli. In the bleomycin model, alpha(v)beta6 antibody was effective in blocking pulmonary fibrosis. At high doses, there was increased expression of markers of inflammation and macrophage activation, consistent with the effects of TGF-beta inhibition in the lung. Low doses of antibody attenuated collagen expression without increasing alveolar inflammatory cell populations or macrophage activation markers.'] Does partial inhibition of integrin alpha ( v ) beta6 prevent pulmonary fibrosis without exacerbating inflammation?