SPHK1 and Alzheimer disease: Unaltered MC degranulation in male skin was concurrent to unchanged local levels of sphingolipid metabolites sphingosine (Figure 3b) and S1P (Figure 3c) and Sphk1 mRNA after OVA treatment compared to saline controls (Figure 3d), confirming the newly identified mechanistic insights we reported that pertained to AD onset [18,19].