However, further research is needed to draw definite conclusion with respect to any pathogenic role in SSc since there are limitations related to the lack of disease specificity for anti-AT1R and anti-ETAR, the use of pooled total serum immunoglobulin G (IgG) rather than affinity purified anti-AT1R and anti-ETAR in the various in vitro and in vivo experiments, and cross-reactivity between AT1R and ETAR [52]. Here, AGTR1 is linked to systemic sclerosis.