CD27 and myeloid sarcoma: The ratio of CD19+CD27+ memory B cells (Bmem) to all B cells after stimulation with 1,25(OH)2D3 was negatively correlated with serum 25(OH)D3 in MS (Spearman’s ρ=–0.594, p=0.042), but positively correlated in NMOSD (Pearson’s r = 0.739, p=0.006).