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

Table 3 Marker levels in patients with highly active antineutrophil cytoplasmic antibody-associated vasculitis before treatment and healthy control subjects

Marker	Active AAV (n = 169)	Healthy control subjects (n = 30)	p Value	AUC^a	COP^b	Sensitivity	Specificity	LR + ^c
CRP, mg/dl	3.79 (0.9–8.24)	0.01 (0.005–0.03)	< 0.0001^d	0.96	0.16	86	97	25.9
TIMP1, ng/ml	333 (226–426)	132 (115–148)	< 0.0001^d	0.94	183	86	97	25.9
LRG1, μg/ml	86.1 (53.7–134)	16.3 (13.6–20.7)	< 0.0001^d	0.97	28.8	93	100	–
TNC, ng/ml	145 (84.3–265)	48.0 (35.4–64.3)	< 0.0001^d	0.88	93.1	72	93	10.8
S100A8/A9, μg/ml	5.8 (3.5–8.9)	1.3 (1.1–1.8)	< 0.0001^d	0.96	2.2	91	93	13.6
CD93, ng/ml	226 (167–300)	125 (103–139)	0.0005^d	0.89	149	82	93	12.3
TKT, ng/ml	124 (69.7–183)	33.1 (15.1–42.6)	< 0.0001^d	0.94	58.1	83	93	12.5
MMP9, ng/ml	791 (429–1382)	517 (294–838)	0.0158^d	0.67	642	62	70	2.05

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
^bCOP is the maximum sum of sensitivity and specificity
^cLR+ at the COP, which equals sensitivity/(1 − specificity)
^d p < 0.05 by analysis of covariance adjusted for age and sex

ISSN: 1478-6362