EDNRA and systemic lupus erythematosus: The basic anti-ETAR antibodies correlated negatively with the total protein level after 3 months (p = 0.03, Figure 6) and with the albumin level after 3 (p = 0.01, Figure 7) and 6 months (p = 0.03, Figure 8) of observation in the systemic lupus erythematosus group.