Article Text

PDF
AB0508 Serum and Urinary Interferon-Gamma-Inducible Protein 10 in Lupus Nephritis
  1. S.I. Nasef1,
  2. A. El-Gohary2,
  3. A. Hegazy3,
  4. M.A.F. Abbas4,
  5. N. Kamel3
  1. 1Rheumatology and Rehabilitation, Faculty of Medicine, Suez Canal University, Ismailia
  2. 2Clinical Pathology, Egypt-Japan University of Science and Technology, Cairo
  3. 3Clinical Pathology
  4. 4Community Medicine, Faculty of Medicine, Suez Canal University, Ismailia, Egypt

Abstract

Background Lupus nephritis (LN) is one of the serious complications of systemic lupus erythematosus (SLE). Finding reliable non-invasive biomarkers for LN will help to improve disease outcomes. IFN-γ-inducible protein 10 (IP-10) is a pro-inflammatory chemokines which is involved in the immunopathogenesis of LN. Thus, we investigated the role of IP-10 as a potential marker of LN.

Objectives To identify the sensitivity, specificity and cut-off value of serum and urinary IP-10 level in LN patients compared to albumin/creatinine ratio and anti-dsDNA.

Methods We included 30 female SLE patients and 10 age-matched healthy female controls. SLE disease activity index (SLEDAI) was calculated. Active SLE was defined as SLEDAI ≥4. Patients were divided into 10 SLE patients with LN, 10 active SLE without LN and 10 inactive SLE patients. Serum and urinary levels of IP-10 were measured by ELISA. Anti-dsDNA and urine albumin/creatinine ratio were measured. Renal biopsy was performed to LN patients.

Results Mean age of patients was 30±10 years versus 32±9 years in controls. Mean disease duration was 52±16 months. Mean SLEDAI was 10.2±3.6.

Active SLE patients had significantly increased serum IP-10 (324±224 pg/dl) and urinary IP-10 (172±206 pg/dl) as compared to inactive SLE (215±188 pg/dl and 121±150 pg/dl respectively) (P<0.01) and healthy controls (103±28 pg/dl and 32±13 pg/dl respectively) (P<0.008).

No significant difference was found in serum and urinary IP-10 levels between active LN and active non-renal patients, even in biopsy-proved proliferative LN patients.

Serum and urinary IP-10 positively correlated with SLEDAI (r=0.416; P<0.02) and (r=0.448, P<0.01) respectively.

By receiver operating characteristics (ROC) analysis, serum and urinary IP-10 could be used to diagnose SLE with serum IP-10 being better [p=0.011, AUC, 95% confidence interval (CI) = 0.772 {0.629–0.915}, P=0.018, AUC 95% CI = 0.753 (0.606–0.901) respectively].

A value of serum IP-10 116.5 pg/ml as a cut-off value is best in differentiating SLE patients from healthy controls with 76% sensitivity and 70% specificity. A value of urinary IP-10 37.9 pg/ml is best in indicating SLE with 70% sensitivity and 70% specificity.

Serum IP-10 could differentiate active from inactive SLE [P=0.007, AUC (95% CI = 0.753 (0.594–0.911)]. It is better than urinary IP-10, albumin/creatinine ratio and anti-dsDNA [AUC {95% CI = 0.654 (0.467–0.841); {0.529 (0.317–0.742)} {607 (402–812)}].

A value of serum IP-10 136 pg/ml is best in differentiating active from inactive SLE with 81% sensitivity and 71% specificity.

Serum and urinary IP-10 did not significantly differentiate either LN from SLE without LN [AUC 95% CI = 0.633 (0.430–0.837), 0.610 (0.397–0.823)], nor active renal SLE from active non renal SLE (AUC [95% CI = 0.533 (0.230–0.837), 0.700 (0.431–0.969)].

Albumin/creatinine ratio is a better marker in differentiating between SLE with LN and SLE without LN [P=0.008, AUC (95% CI = 0.803 (0.610–0.995)]

Any of the serum and urinary IP-10, albumin/ creatinine ratio, and anti-dsDNA didn't correlate with the class of lupus nephritis (P=0.658, 0.647, 0.807 and 0.069 respectively).

Conclusions Serum and urinary IP-10 are useful markers of lupus activity; however, they are not indicative of renal activity. Albumin/creatinine ratio is superior in identifying LN and renal activity.

Disclosure of Interest None declared

Statistics from Altmetric.com

Request permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.