A role for MCP-1/CCR2 in interstitial lung disease in children

Background: Interstitial lung diseases (ILD) are chronic inflammatory disorders leading to pulmonary fibrosis. Monocyte chemotactic protein 1 (MCP-1) promotes collagen synthesis and deletion of the MCP-1 receptor CCR2 protects from pulmonary fibrosis in ILD mouse models. We hypothesized that pulmonary MCP-1 and CCR2(+) T cells accumulate in pediatric ILD and are related to disease severity. Methods: Bronchoalveolar lavage fluid was obtained from 25 children with ILD and 10 healthy children. Levels of pulmonary MCP-1 and Th1/Th2-associated cytokines were quantified at the protein and the mRNA levels. Pulmonary CCR2(+), CCR4(+), CCR3(+), CCR5(+) and CXCR3(+) T cells were quantified by flow-cytometry. Results: CCR2(+) T cells and MCP-1 levels were significantly elevated in children with ILD and correlated with forced vital capacity, total lung capacity and ILD disease severity scores. Children with lung fibrosis had significantly higher MCP-1 levels and CCR2(+) T cells in bronchoalveolar lavage fluid compared to non-fibrotic children. Conclusion: The results indicate that pulmonary CCR2(+) T cells and MCP-1 contribute to the pathogenesis of pediatric ILD and might provide a novel target for therapeutic strategies.