Failure to detect Xenotropic murine leukaemia virus-related virus in Chinese patients with chronic fatigue syndrome

Table 2 Optimization of CIC concentration

(1) Multiplex real-time PCR
pACYC-MS2- IC-2V plasmid CIC concentration (copies/μl)	pACYC-MS2-2V plasmid standard 1 × 10⁵copies/μl		pACYC-MS2-2V plasmid standard 1 × 10⁴copies/μl		pACYC-MS2-2V plasmid standard 1 × 10³copies/μl		pACYC-MS2-2V plasmid standard 1 × 10²copies/μl		XMRV 0 copies/μl
	CIC (HEX)Ct	XMRV (FAM)Ct	CIC (HEX)Ct	XMRV (FAM)Ct	CIC (HEX)Ct	XMRV (FAM)Ct	CIC (HEX)Ct	XMRV ((FAM)Ct	CIC (HEX)Ct
100000	39.22	28.79	32.18	31.58	28.92	34.81	28.50	No Ct	28.34
10000	37.85	28.12	31.26	31.06	32.36	34.56	31.45	44.26	31.55
1000	39.52	24.73	37.20	27.76	31.50	31.18	35.79	34.28	34.11
0	No Ct	24.69	No Ct	28.47	No Ct	30.73	No Ct	33.81	No Ct
(2) Multiplex real-time RT-PCR
Armored RNA concentration (IU/ml)	Armored RNA standard 1 × 10 ⁵ IU/ml		Armored RNA standard 1 × 10 ⁴ IU/ml		Armored RNA standard 1 × 10 ³ IU/ml		Armored RNA standard 1 × 10 ² IU/ml		XMRV 0 IU/ml
	CIC (HEX)Ct	XMRV (FAM)Ct	CIC (HEX)Ct	XMRV (FAM)Ct	CIC (HEX)Ct	XMRV (FAM)Ct	CIC (HEX)Ct	XMRV (FAM)Ct	CIC (HEX)Ct
100000	39.50	25.24	30.89	28.28	27.12	No Ct	26.35	No Ct	26.07
10000	37.96	25.00	30.70	28.22	30.37	31.17	27.79	37.06	29.49
1000	No Ct	25.25	30. 65	28.03	33.18	31.14	33.87	34.40	33.27
0	No Ct	25.18	No Ct	27. 82	No Ct	30.78	No Ct	37.11	No Ct

Ct values indicate the standard concentrations. A sample with Ct > 45 cycles was considered to be negative. Concentrations of XMRV DNA/RNA and pACYC-MS2-2V plasmid/armored RNA standard were indicated by FAM and HEX signals, respectively.

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