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  • Open Access

Urinary VCAM-1 as a biomarker of lupus nephritis disease activity

  • 1,
  • 1,
  • 1,
  • 1,
  • 2,
  • 3,
  • 3,
  • 4 and
  • 1
Pediatric Rheumatology201412 (Suppl 1) :P108

https://doi.org/10.1186/1546-0096-12-S1-P108

  • Published:

Keywords

  • Lupus Nephritis
  • Active Lupus Nephritis
  • British Isle Lupus Assessment Group
  • Juvenile Systemic Lupus Erythematosus
  • Renal Survival Rate

Introduction

Up to 80% of children with Juvenile Systemic Lupus Erythematosus (JSLE) develop lupus nephritis (LN) (1), with the 5-year renal survival rate varying between 44-94% (2-4). Conventional markers of JSLE disease activity fail to adequately predict impending LN flares (5), with significant renal involvement (class III, IV or V LN) known to occur with low level proteinuria (6). Cross-sectional adult SLE studies have shown urinary vascular cell adhesion molecule-1 (VCAM-1) to be significantly higher in active LN than inactive LN or healthy controls, correlating with traditional markers of LN disease activity (7, 8).

Objectives

To investigate the role of VCAM-1 as a urinary biomarker in JSLE.

Methods

Urinary VCAM-1 concentrations were measured by ELISA (R&D Systems Ltd). The assay demonstrated 108-122% linearity of dilution, and 90-106% recovery using spike and retrieval techniques. Samples were diluted 1 in 80, and re-run at different dilutions where necessary. JSLE patients were classified as ‘JSLE active renal’ or ‘JSLE non-active renal’ based on the renal domain of the British Isles Lupus Assessment Group score (BILAG) (rBILAG A/B vs. D/E). Healthy children (HC), attending for non-inflammatory surgery were recruited as controls. Demographic, clinical and biomarker data were not normally distributed, and expressed as median values and interquartile ranges (IQR). Mann-Whitney U test was used when comparing between groups, and correlations utilized the Spearman rank test.

Results

Sixty-seven patients participated in the study (50 JSLE patients and 17 healthy controls). JSLE patients had a median age of 16.5 years (range 10.07-21.91), and 36/50 (72%) were female. All JSLE patients had a median of 5 ACR classification criteria (IQR 4-7), with a median length of disease of 4.66 years (IQR 3.2-7.5). 23 (46%) JSLE patients were classed as JSLE active renal disease and 27 (54%) were JSLE non-active renal. Eleven (22%) JSLE patients had previously undergone a renal biopsy: Class IV LN (n=3), Class III (n=6) and Class II (n=2). The healthy controls had a median age of 12 years (range 4.0-16.0), with 5 being female (29%).

Urinary VCAM-1 levels were significantly higher in JSLE active renal patients (16.65 ng/mgCr [IQR 2.58-51.78]), versus non-active renal patients (2.3ng/mgCr [IQR 0.61-10.01], p=0.002) and HC's (2.4ng/mgCr [0.54-4.50], p=0.003). A statistically significant correlation was seen between VCAM-1 levels, C3 (r= -0.38, p=0.009) and urinary albumin-to-creatinine (UAUC) ratio (r=0.49, p=0.001).

Conclusion

We have shown for the first time in children, that urinary VCAM-1 is able to identify patients with active renal lupus. Further assessment is required in prospective longitudinal studies.

Disclosure of interest

None declared.

Authors’ Affiliations

(1)
Institute of Translational Medicine, Women and Children's Health, University of Liverpool, UK
(2)
Department of Paediatric Nephrology, Alder Hey Children's Hospital, Liverpool, UK
(3)
Paediatric Nephrology Department, Great Ormond Street Hospital, London, UK
(4)
Department of Paediatric Rheumatology, Great Ormond Street Hospital, London, UK

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