MERTK and systemic sclerosis: Of note, cultured MDMs from SSc-ILD patients showed a significantly higher protein synthesis of CD206 (other cell membrane marker of M2 phenotype) and the functional marker MerTK compared of cultured MDMs from HSs and from SSc patients no-ILD (CD206: p < 0.05; MerTK: p < 0.01 vs. HS; p < 0.05 vs. SSc patients no-ILD) (Fig. 2A).