Low Urine Secretion of Semaphorin3A In Lupus Patients With Proteinuria

Abstract

Background: Immune semaphorins are important players in controlling both innate and adaptive immune responses. The regulatory role of semaphorin3A (sema3A) in systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and other autoimmune diseases is widely reported. Decreased levels of serum sema3A were shown to be associated with SLE disease activity. Objectives: To assess urine concentrations of sema3A in SLE patients and its correlation with renal involvement and disease activity. Methods: Urine levels of sema3A were analyzed in 38 SLE patients of whom 13 had renal involvement and were compared to 10 healthy controls and 8 RA patients (disease control group). Results: The secretion of urine sema3A was found to be significantly lower in SLE patients compared to healthy controls and RA patients (4.9±3.9 ng/ml, 8.5±2.7 ng/ml, 9.85±1.7 ng/ml, respectively, p = 0.0006). Urine sema3A was significantly lower in SLE patients with lupus nephritis than in patients without nephritis (4.0±3.4 ng/ml vs 6.5±3.8 ng/ml, p=0.03). Urine sema3A was inversely correlated with proteinuria and SLE disease activity. Conclusion: Urine sema3A is decreased in lupus patients and should be further evaluated as a possible biomarker for disease activity and renal involvement.