AGTR1 and systemic sclerosis: Pathogenic and functionally active Abs such as those against angiotensin 1 receptor (AT1R), endothelin A receptor (ETAR), C-X-C motif chemokine receptor 3 (CXCR3), and CXCR4 have been reported in the sera of SSc patients, regulating the spectrum of clinical manifestations (9, 11–14).