DLL4 and systemic lupus erythematosus: ELISA and immunohistochemical staining were performed on clinical blood samples and renal biopsies, respectively, to compare Dll4 expression levels between systemic lupus erythematosus (SLE) patients without LN (non-renal SLE) and those with LN.<h4>Results</h4>We found that the number of ECs was increased during LN process and ECs exhibited cellular heterogeneity, among which EC subcluster EC-1 was identified as a potential regulator of MCs, possibly through the Dll4/Notch3 axis.