Objective To investigate the associations between serum levels of antinuclear antibody (ANA), anti-double-stranded DNA antibody (anti-dsDNA), and monocyte chemoattractant protein-1 (MCP-1) and renal injury in patients with systemic lupus erythematosus (SLE).

Methods A case-control study was conducted involving 180 patients with SLE, who were divided into renal injury group (n=60) and non-renal injury group (n=120) based on presence or absence of renal involvement. The positive rates of ANA and anti-dsDNA and serum MCP-1 levels were compared between the two groups. Additionally, laboratory parameters were compared between anti-dsDNA-positive and anti-dsDNA-negative patients within the renal injury group. Pearson correlation analysis was used to assess the relationships between serum MCP-1 levels and renal function markers. Receiver operating characteristic (ROC) curves were constructed to evaluate the diagnostic performance of anti-dsDNA and MCP-1 for renal injury in SLE.

Results There was no significant difference in the positive rate of ANA between the renal injury group (95.00%) and the non-renal injury group (91.67%) (P>0.05). The positive rate of anti-dsDNA in the renal injury group (71.67%) was higher than that in the non-renal injury group (50.83%), and the serum MCP-1 level in the renal injury group was higher than that in the non-renal injury group, with statistically significant differences (P < 0.05). ROC curve analysis showed that the areas under the curves (AUCs) for anti-dsDNA and MCP-1 in diagnosing renal injury in SLE patients were 0.608 (95%CI, 0.522 to 0.695) and 0.668 (95%CI, 0.574 to0.762), respectively. The levels of hemoglobin (Hb), red blood cells (RBC), albumin (ALB), immunoglobulin A (IgA), immunoglobulin G (IgG) and complement C3 in patients in the renal injury group were all lower than those in patients in the non-renal injury group, the levels of red cell distribution width (RDW), β₂-microglobulin (β₂-MG), cystatin C (Cys-C), serum creatinine (SCr), blood urea nitrogen (BUN) and uric acid (UA) were all higher than those in patients in the non-renal injury group, with statistically significant differences (P < 0.05). The levels of β2-MG, Cys-C, SCr, BUNand UA in anti-dsDNA-positive patients were all higher than those in anti-dsDNA-negative patients, with statistically significant differences (P < 0.05). Pearson correlation analysis results showed that serum MCP-1 levels in SLE patients with renal injury were significantly positively correlated with the levels of β2-MG, Cys-C, SCr, BUN and UA (r=0.711, 0.684, 0.593, 0.402, 0.441, P < 0.001).

Conclusion Serum ANA has no significant association with renal injury in SLE patients, while positive anti-dsDNA and high expression of MCP-1 are closely related to renal injury. The diagnostic efficacy of MCP-1 and anti-dsDNA for SLE renal injury is general. It is recommended to combine their detection with renal function indicators for a more accurate assessment of the degree of renal injury.