CXCR4 and silicosis: Activated fibroblasts further enhance the pro-fibrotic phenotype of macrophages via secretion of Cxcl12, reinforcing the Cxcr4 signalling axis and establishing a stable positive-feedback loop.<h4>Conclusion</h4>Our findings suggest that silicosis-associated fibrosis progresses through a positive feedback loop involving interactions between Cxcr4<sup>+</sup> AM macrophages and Cxcl12<sup>+</sup> fibroblasts.