Serum and Urinary Interferon-Gamma-Inducible Protein 10 in Lupus Nephritis

BackgroundLupus nephritis is a serious manifestation of systemic lupus erythematosus (SLE). The objective of this study was to identify the sensitivity, specificity, and cut-off values of IP-10 in the serum and urine of patients with lupus nephritis compared to renal biopsy, albumin/creatinine ratio, and serum anti-dsDNA. MethodsThirty female SLE patients were included. SLEDAI was calculated and blood and urine samples were collected. Patients were divided into 10 SLE patients with renal involvement (six active and four inactive), 10 active SLE, and 10 inactive SLE patients. Ten age-matched healthy (control) were included. Serum and urinary levels of IP-10 were measured by ELISA. Anti-dsDNA, urine albumin/creatinine ratio were performed. ResultsSerum and urinary IP-10 in active SLE patients had significantly increased levels as compared to inactive SLE patients (P = 0.015, P = 0.033, respectively). However, there was no difference in serum and urinary levels between active renal and active non-renal patients. Albumin/creatinine ratio is a better marker in differentiating between lupus nephritis and SLE with no renal involvement. Any of serum and urinary IP-10, albumin/creatinine ratio, and anti-dsDNA did not correlate with the class of lupus nephritis in renal biopsy. ConclusionUrinary and serum IP-10 are useful markers of lupus activity, but not indicative of renal activity. Albumin/creatinine ratio is superior in identifying lupus nephritis and renal activity.