Objective To analyze the change in levels of high mobility group box 1 protein (HMGB1), interleukin-32 (IL-32), matrix metalloproteinase-9 (MMP-9)/tissue inhibitor of metalloproteinase-1 (TIMP-1) in peripheral blood of patients with lupus nephritis (LN) and their values in predicting prognosis.

Methods A total of 86 patients with LN from October 2021 to June 2023 were selected and treated with induction therapy for 6 months. Based on remission status of the disease, patients were divided into remission group (n=66) and non-responder group (n=20). Baseline data, change in levels and reduction rates of HMGB1, IL-32 and MMP-9/TIMP-1, and the partial correlation of reduction rates of HMGB1, IL-32 and MMP-9/TIMP-1 levels in peripheral blood with treatment response as well as their predictive values for treatment response were compared between the two groups. Disease progression was compared between patients with different reduction rates of HMGB1, IL-32 and MMP-9/TIMP-1.

Results HMGB1, IL-32 and MMP-9/TIMP-1 levels in the remission group decreased significantly at 1 and 3 months after treatment compared to before treatment (P < 0.05); the levels of HMGB1, IL-32 and MMP-9/TIMP-1 in the remission group were significantly lower than those in the non-responder group at 1 and 3 months after treatment (P < 0.05); the reduction rates of HMGB1, IL-32 and MMP-9/TIMP-1 levels in the remission group were significantly higher than those in the non-responder group at 1 and 3 months after treatment (P < 0.05). Partial correlation analysis showed that the reduction rates of HMGB1, IL-32 and MMP-9/TIMP-1 levels were independently significantly correlated with treatment response (P < 0.05). One and three months after treatment, the values of the area under the curve (AUC) for the combined prediction of remission by the reduction rates of HMGB1, IL-32 and MMP-9/TIMP-1 levels were 0.910 and 0.932 respectively, with the AUC being the largest at 3 months after treatment (P < 0.05). Patients were divided into high and low reduction rate subgroups based on theoptimal cut-off value from the ROC curve analysis at 3 months after treatment, and the disease progression rate was significantly lower in the high reduction rate subgroup than in the low reduction rate subgroup for HMGB1, IL-32 and MMP-9/TIMP-1 (P < 0.05).

Conclusion The great change in levels of HMGB1, IL-32 and MMP-9/TIMP-1 in peripheral blood of LN patients is significantly correlated with treatment response and disease progression, and the combined detections of HMGB1, IL-32 and MMP-9/TIMP-1 levels at 1 and 3 months after treatment have high value in predicting the treatment response of LN patients.