Assessment of circulating MCP-1 level and 2518A>G gene polymorphism in systemic lupus erythematosus

Lupus nephritis (LN) is a major contributor to morbidity and mortality in patients with Systemic Lupus Erythematosus (SLE). This study aims to investigate the possible role of a functional polymorphism in the regulatory region of the monocyte chemo-attractant protein-1 (MCP-1) gene and MCP-1 blood level in the diagnosis of LN and in correlating the MCP-1 blood levels with disease activity. The study included 56 SLE patients and 56 controls. All the SLE patients suffered from LN. An analysis of MCP-1 gene polymorphism by polymerase chain reaction was performed followed by restriction fragment length polymorphism (PCR-RFLP) analysis and MCP-1 blood level was determined using the ELISA technique. Calculation of Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) was performed. Serologic tests included the determination of antinuclear antibody (ANA) and anti-double-stranded (ds) DNA antibodies, Complement C3 and C4 levels. A significant increase in the frequency of genotype A/G and a decrease in the frequency of genotype A/A were found among patients with active LN compared to inactive LN. There was a statistically significant difference in the blood level of MCP-1 between LN patients and controls. Also, MCP-1 blood levels were significantly higher in active LN patients than inactive LN. A significant positive linear correlation was detected between MCP-1 blood level and SLEDAI, creatinine, and 24 hours protein in LN patients. These results suggest that an A/G genotype together with the measurement of the blood level of MCP-1 can be a useful tool for detection and follow up of active LN.