TABLE IV.

Effect of omalizumab on FcεRIα expression^* in unstimulated PBMCs and pDCs^†

Mechanistic parameter			Omalizumab			Omalizumab		Placebo
Cell type	Method measured	Readout*	No.	Prerandomization, mean (SD)	Postrandomization, mean (SD)	Ratio of geometric means (95% CI)	P value	No.	Prerandomization, mean (SD)	Postrandomization, mean (SD)	Ratio of geometric means (95% CI)	P value
pDCs‡	Flow cytometry	Surface FcεRIα expression	64	3231.2 (1.7)	1381.7 (1.6)	0.43 (0.37–0.49)	<.001	23	3540.0 (1.6)	3974.9 (1.6)	1.12 (0.85–1.48)	.40
PBMCs	RT-PCR	FCER1A mRNA	64	1.9 (1.8)	1.9 (1.7)	1.02 (0.91–1.13)	.78	23	1.5 (1.8)	1.3 (2.1)	0.85 (0.67–1.08)	.17
Purified pDCs	RT-PCR	FCER1A mRNA	18	0.4 (1.7)	0.4 (1.9)	1.07 (0.80–1.42)	.62	7	0.3 (2.1)	0.2 (1.7)	0.69 (0.53–0.9)	.02

Boldface indicates P < .05.

^*FCER1A mRNA values represent expression measured before ex vivo stimulation and normalized to HPRT expression (2^−Δct).

^†Means are geometric means, and SDs are geometric SDs.

^‡pDCs and basophils gated in total PBMCs for flow cytometric analysis (unstimulated cells).