Figure 5.

Levels of the sphingolipid metabolites S1P and dihydro-S1P in pristane-induced lupus in mice. A) S1P (left panel) and dihydro-S1P (right panel) levels in the serum from untreated and pristane-treated SphK2^+/+ and SphK2^−/− mice were measured by LC-ESI-MS/MS. Data are expressed as picomoles per milliliter and are means ± sd (n = 4 mice/group). B) Expression of SphK2 in clinical lupus patients. Expression of SphK2 in PBMCs isolated from healthy volunteers (n = 10) and lupus patients (n = 22). mRNA levels of SphK2 were determined by quantitative PCR and normalized to β-actin. Statistical significance was determined by ANOVA with a post hoc Tukey’s test; n.s., not significant. *P < 0.05, **P < 0.005, ***P < 0.001.