Clinico-serological associations of urinary activated leukocyte cell adhesion molecule in systemic lupus erythematosus and lupus nephritis

Abstract

BackgroundLupus nephritis (LN) is one of the major complications associated with Systemic Lupus Erythematosus (SLE). Activated leukocyte cell adhesion molecule (ALCAM or CD166) is a promising urine biomarker that binds to CD6, a receptor found on lymphocytes. This binding results in T-cell activation, proliferation, and recruitment, which causes tissue inflammation and may explain the pathophysiology of LN.Aim of workInvestigate the urinary ALCAM level in SLE, study its relationship to disease activity, and clarify the association with LN activity and histopathology.Patients and methodsA case–control study was performed on 60 patients with SLE and 20 matched controls. The SLE disease activity index (SLEDAI) and the activity of renal disease (rSLEDAI) were evaluated. Renal biopsy and uALCAM levels were also investigated.ResultsUrinary ALCAM levels were higher significantly in active LN patients than inactive LN patients, active and inactive non-LN SLE, and the control group (p < 0.001). The cut-off value for identifying active and inactive LN was above 270 ng/mg (p < 0.001). ALCAM levels were greater in proliferative (class III, IV, and IV/V) than in non-proliferative (class II and V) LN (p < 0.001). ALCAM exhibited high positive correlations with SLEDAI and rSLEDAI (p < 0.001 each) and negative significant correlations with C3 (p < 0.001) and C4 (p = 0.005).ConclusionUrinary ALCAM is a sensitive biomarker evaluating LN in SLE patients. Levels above 270 ng/mg can help distinguish between active and inactive LN. ALCAM levels are correlated positively with SLEDAI and rSLEDAI but have a negative correlation with C3 and C4.Key Points• Urinary ALCAM shows promise as a biomarker for evaluating kidney dysfunction in SLE patients.• It is a non-invasive marker that can differentiate between proliferative and non-proliferative LN.• A urinary ALCAM level above 270 ng/mg can indicate active LN, while lower levels indicate inactive LN.• Urinary ALCAM levels are correlated positively with SLEDAI and rSLEDAI scores but correlated negatively with C3 and C4.