Seasonal 25-hydroxyvitamin D levels in new childhood-onset SLE: associations with disease activity and peripheral lymphocyte subsets - Chenxi Wei; Shufeng Zhi; Jiayin Li; Lijun Jiang; Xue Zhao; Qingxiao Su; Xingjie Qi; Hui Zhao; Zanhua Rong (Lupus Science & Medicine, 2026)