Targeted proteomics reveals promising biomarkers of disease activity and organ involvement in antineutrophil cytoplasmic antibody-associated vasculitis

Table 2 Marker levels in highly active antineutrophil cytoplasmic antibody-associated vasculitis before treatment and remission at 6 months

Marker	Highly active (n = 62)	Remission (n = 62)	p Value	AUC^a	COP^b	Sensitivity	Specificity	LR + ^c
CRP, mg/dl	6.34 (2.14–11.5)	0.06 (0.01–0.16)	< 0.0001^d	0.93	1.22	82	95	17.0
TIMP1, ng/ml	329 (250–405)	156 (134–175)	< 0.0001^d	0.93	205	92	89	8.14
LRG1, μg/ml	151 (110–231)	40.1 (29.8–62.0)	< 0.0001^d	0.9	71.9	89	85	6.11
TNC, ng/ml	144 (97.7–272)	47.0 (37.0–68.3)	< 0.0001^d	0.88	72.7	90	79	4.31
S100A8/A9, μg/ml	6.4 (4.4–10.3)	2.2 (1.2–3.8)	< 0.0001^d	0.86	4.1	77	82	4.36
CD93, ng/ml	192 (151–252)	124 (103–164)	< 0.0001^d	0.78	146	79	69	2.58
TKT, ng/ml	104 (61.8–162)	52.0 (28.9–91.5)	< 0.0001^d	0.72	115	47	90	4.83
MMP9, ng/ml	909 (447–1623)	566 (330–839)	0.0007^d	0.67	897	53	77	2.36
MPO-ANCA,^e U/ml	63.5 (27.4–223)	0.8 (0.5–2.2)	< 0.0001^d	0.96	5.1	98	88	7.83

Abbreviations: ANCA Antineutrophil cytoplasmic antibody, COP Cutoff point, CRP C-reactive protein, LR Likelihood ratio, LRG1 Leucine-rich alpha-2-glycoprotein 1, MMP9 Matrix metalloproteinase 9, MPO Myeloperoxidase, TIMP1 Tissue inhibitor of metalloproteinase 1, TKT Transketolase, TNC Tenascin C
Values are median (IQR)
^aAn AUC of 1 indicates perfect discrimination between groups; an AUC of 0.5 indicates no discrimination
^bThe maximum sum of sensitivity and specificity
^cPositive likelihood ratio at the COP, which equals sensitivity/(1 − specificity)
^d p < 0.05 by Wilcoxon signed-rank test
^eOnly MPO-ANCA-positive patients (n = 48)

ISSN: 1478-6362