TNFSF11 and systemic lupus erythematosus: IL-1 and IL-6 appear to play a similar role in bone metabolism.75 Low-density lipoproteins, which may be elevated in SLE, also contribute to T lymphocyte activation, RANKL and TNF induction, and osteoblast quantity reduction.76 However, all mechanisms of a relationship between SLE activity, vitamin D levels, BMD, and markers of bone synthesis and resorption are not precisely known and require further investigation.