ESR1 and systemic lupus erythematosus: As a result of the minor expression of ERβ in SLE patients with SLEDAI-2K scores ≥6, an increased ERα/ERβ ratio was detected in T lymphocytes from this group of patients as compared to those with SLEDAI-2K scores <6 (p = 0.0016) and healthy controls (p = 0.0249), Fig. 1d (left panel).