CXCL13 predicts disease activity in early rheumatoid arthritis and could be an indicator of the therapeutic `window of opportunity'

Table 2 Correlations of CXCL13 plasma levels with disease activity parameters at baseline and following 6 months of treatment

Time	Disease marker	0 months rho (P)	6 months rho (P)
Baseline
	IgM-RF	-0.112 (0.34)	0.073 (0.54)
	Anti-CCP	0.021 (0.86)	0.099 (0.31)
	TSS	-0.011 (0.92)	0.059 (0.62)
	Swollen joint count 28	0.336 (0.003)	0.110 (0.35)
	Tender joint count 28	0.166 (0.16)	0.001 (0.99)
	Swollen joint count 40	0.392 (0.001)	0.177 (0.13)
	Tender joint count 40	0.162 (0.17)	0.007 (0.95)
	VAS doctor global	0.378 (0.001)	0.103 (0.38)
	CRP	0.094 (0.42)	0.145 (0.21)
	DAS28CRP	0.205 (0.078)	0.089 (0.45)
	SDAI	0.254 (0.028)	0.091 (0.44)
12 months
	Swollen joint count 28	0.131 (0.27)	-0.077 (0.51)
	Tender joint count 28	0.195 (0.096)	-0.012 (0.92)
	Swollen joint count 40	0.162 (0.17)	-0.085 (0.47)
	Tender joint count 40	0.219 (0.060)	0.045 (0.71)
	VAS doctor	0.006 (0.96)	-0.037 (0.76)
	CRP	-0.047 (0.69)	-0.124 (0.30)
	DAS28CRP	0.059 (0.62)	0.012 (0.92)
	SDAI	0.009 (0.94)	0.047 (0.67)

Correlations of clinical data with the plasma level of CXCL13 measured at 0 months and after 6 months of treatment, in the OPERA trial. Correlations are presented as Spearman's rho (P value). P values lower that 0.05 are considered statistically significant (indicated by bold). Statistically significant correlations between plasma CXCL13 level and disease parameters were observed at baseline, but not following treatment. Anti-CCP: anti-citrullinated protein antibody; CXCR13: C-X-C chemokine receptor type 13; CRP: C-reactive protein; DAS28CRP: disease activity in 28 joints, four variables, C-reactive protein based; IgM-RF: IgM rheumatic factor; OPERA: OPtimized treatment algorithm in Early Rheumatoid Arthritis; SDAI: simple disease activity index; TSS: total Sharp score; VAS: visual analog scale.

ISSN: 1478-6362