ACE and sarcoidosis: Parameters suitable for gauging the activity of the macrophage lineage in ILDs and specifically sarcoidosis and occupational diseases have been delineated and comprise the angiotensin converting enzyme (ACE) a product of epithelioid cells that reflect the granuloma burden of the entire body, neopterin a metabolite of the guanosinetriphosphate pathway that is released by activated macrophages and monocytes under the control of IFN-γ produced by T-cells [45] and b-glucuronidase a lysosomal enzyme, associated with increased phagocytic activity [46].