Sarcoidosis and Th1 chemokines

Many studies have shown high levels of the chemokine Interferon-γ-inducible protein 10 (IP-10) and its chemokine (C-X-C motif) receptor (CXCR) 3, expressed on Type-1 helper (Th1) lymphocytes, in bronchoalveolar lavage (BAL) and biopsy samples of patients with sarcoidosis. The levels of IP-10 and the other CXCR3 ligands, Monokine induced by IFN-γ (MIG) and Interferon-inducible T-cell α chemoattractant (I-TAC), in bronchoalveolar lavage fluid (BALF) were correlated with the numbers of both total and CD4(+) lymphocytes. Alveolar macrophages were stained positive for all CXCR3 ligands and produced increased amounts of these chemokines. This positive staining was also observed in the epithelioid and giant cells in the sarcoid lungs. These findings suggest that IP-10, MIG and I-TAC play important roles in the accumulation of Th1 lymphocytes in sarcoid lungs. Furthermore, it has been demonstrated that circulating IP-10 levels correlated with measures of disease severity in sarcoidosis, and that its serial measurements corresponded to the clinical course of the disease, suggesting that IP-10 is a potentially useful biomarker of sarcoidosis and its severity.