Studies on expression and therapeutsc approach of CD13 in granulomefous lung diseases

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The cell-surface glycoprotein CD13 first identified in leukocytes of the myeloid series is identical to aminopeptidase N (EC 3.4.11.2), Since aminopeptidase expression was shown to be up-regulated by a Th1-related cytokine, interferon-y, we examined here the significance of CD13/aminopeptidase N in pulmonary sarcoidosis. The activity of aminopeptidase in bronchoalveolar lavage fiuid (BALF) was signaficantly higher in sarcoidosis paitents than in normal volunteers (NV) and control patients (CP). The activity significantly correlated with activity of pulmonary sarcoidosis. CD13/aminopeptodase N proein, which has a molecular mass of approximately 150 Kd, was detectable in alveolar macrophages (AM) from sarcoidosis patients at higher levels than in those from NV. CD13/aminopeptidase N induced in vitro chemotactic migration of human lymphocytes in a concentation rage of 10^<-5>-10^<-4> U/ml. The chemotactic activity was greater for CD4+ T lymphocytes than CD8+ T lymphocytes. The enzymatic activity of CD13/aminopeptidase N, abolished the chemotactic activity. Higher chemotactic activity for lymphocytes was detected in the BALF from sarcoidosis patients that in that from NV, and the activity was significantly decreased by the treatment with bestatin. Moreover, we found that bestatin can suppress the proinflammatory cytokines by AM from patients with sarcoidosis.This study indicated that CD13/aminopeptidase N expressed in AM may have a role in T lympphocyte involvement in the lung of sarcoidosis and the pahogenesis of alveolitis in this disorder.