Table 2.

Relative mRNA expression of eight genes in different human cells

Genes	SCs	Mast cells	Endothelial cell
AHR pathway
AHR	426	11	6
AHRR	200	1,342	78
ARNT	1,105	492	479
Trp metabolism
IDO1	10	NE	2
IDO2	NE	NE	NE
TDO2	14	3	NE
Myelin markers
S100B	66,360	2	6
MPZ	24,336	4	5

AHR is predominantly expressed in SCs compared with mast cells and endothelial cells. Total RNA was isolated from normal human tissues. The gene mRNA levels (calculated as described in Materials and Methods) were based on the amount of the target message relative to the endogenous control TBP message, to normalize the starting amount and quality of total RNA. NE, not expressed.