Immune response CC chemokines CCL2 and CCL5 are associated with pulmonary sarcoidosis

BALF chemokine levels from 72 patients affected by pulmonary sarcoidosis were analyzed by enzyme-linked immunosorbent assay (ELISA) and compared to 8 healthy volunteers. BALF CCL3 and CCL4 levels from pulmonary sarcoidosis patients were not increased compared to controls. However, CCL2 and CCL5 levels were elevated, and subgroup analysis showed higher levels of both chemokines in all stages of pulmonary sarcoidosis. CCL2, CCL5, CC chemokine receptor type 1 (CCR1), CCR2 and CCR3 were expressed from mononuclear cells forming the lung granulomas, while CCR5 was only found on mast cells.These data suggest that CCL2 and CCL5 are important mediators in recruiting CCR1, CCR2, and CCR3 expressing mononuclear cells as well as CCR5-expressing mast cells during all stages of pulmonary sarcoidosis.Sarcoidosis is an immune-mediated multisystem disease of unknown etiology [1]. It involves the lung in over 90% of the cases and is a common cause of interstitial lung disease with some patients eventually requiring lung transplantation [1-3]. Pulmonary sarcoidosis is diagnosed via compatible clinicoradiographic findings with histological evidence of non-necrotizing granulomas in the absence of infection or other causative etiologies that can also cause pulmonary granulomas [4]. Pathologically, sarcoidosis is characterized by an initial T cell alveolitis that is dominated by a type 1 immune response environment [5-7]. This response leads to the recruitment and activation of mononuclear cells that eventually evolves into non-necrotizing granulomas [4,5]. Importantly, at some point between the transition from stage I to III pulmonary sarcoidosis there may be a conversion from a local inflammatory type 1 response to a more fibroproliferative type 2 response where inflammation gives way to pulmonary fibroplasia.Chemokines recruit mononuclear cell subpopulations via specific receptors [8]. Different types of chemokines have been implicated in early and late stages of sarcoidosis [9]. For i