Systemic sclerosis (SSc) is a complex autoimmune connective tissue disease characterized by microvascular damage, immune system reactivity and progressive fibrosis of skin and internal organs. Interstitial lung disease is the leading cause of death for SSc patients (SSc-ILD), and the process of lung fibrosis involves also circulating monocytes and alveolar macrophages.

Prevalence of hybrid TLR4+M2 monocytes/macrophages in peripheral blood and lung of systemic sclerosis patients with interstitial lung disease