Urinary MCP-1 as a Biomarker for Lupus Nephritis

Systemic lupus erythematosus (SLE) is a multisystemic, autoimmune disorder which is episodic in nature with a broad spectrum of clinical and immunological manifestations. As the course of lupus nephritis (LN) is often unpredictable, it is important to identify reliable, noninvasive methods to repeatedly assess the condition of the kidneys in those patients during follow-up. To assess the potential use of monocyte chemotactic protein 1 (MCP 1) as a marker for disease activity in LN, 56 SLE patients were recruited. They were divided into three groups, one with active LN (n=19), another with inactive LN (n=25) and a third formed of SLE patients who had no renal affection. Two other groups were added for comparison, one formed of 12 cases who had non- lupus nephritis and another of age and sex matched controls (n=19). Urinary MCP 1 /creatinine ratio was found to be signifi-cantly higher in the two groups of active nephritis both lupus and non lupus (p 0.0001). Among lupus groups, it correlated positively with rSLEDAI (7=0.486,p=0.0001) as well as with other known markers of lupus activity including the ESR (7=0.582, p=0,0001), leucopenia and hypertension. Also, across all the study groups, the MCP l/creatinine ratio corre-lated positively with the protein/creatinine ratio (7=0.551, p 0.0001). Urinary MCP l/creatinine ratio increases in active nephritis regardless of its cause and thus it can be used as a non-invasive indicator of active renal affection in known cases of SLE.