Following the results obtained from the lung samples analysis, 26 SSc patients with ILD (mean age 63 ± 14 years old), 14 SSc patients without ILD (mean age 63 ± 19 years old) and 15 age-matched HSs were enrolled for flow cytometry analysis to investigate the phenotype (hybrid TLR4+M2 and M2) of circulating monocytes. The gene discussed is TLR4; the disease is systemic sclerosis.