Abstract Objective To investigate the application of peripheral blood mononuclear cell (PBMC) programmed death ligand-2 (PD-L2) molecule in systemic lupus erythematosus (SLE). Methods The clinical data of 30 patients with SLE admitted to Pingxiang People′s Hospital from January 2019 to January 2020 were retrospectively analyzed. A total of 15 patients with lupus nephritis at active stage with SLE disease activity index (SLEDAI) score >5 points were included into the active group, a total of 15 patients with lupus at remission stage with SLEDAI score ≤5 points were included into the remission group, a total of 10 patients with rheumatoid arthritis (RA) treated in Pingxiang People′s Hospital during the same period were selected as active control cases and included in the RA group, and 10 healthy volunteers who received physical examination were included in the normal control group. All selected candidates received PD-L2 molecular detection of PBMC, the application value of PD-L2 molecule expression level of PBMC in SLE patients was analyzed. Results There was no statistical significant difference in the expression level of PD-L2 molecule in SLE patients with different gender, age and weight (P>0.05); The expression level of PD-L2 molecule of patients in the active group was higher than that in patients of the remission group and the normal control group, and the differences were statistically significant (P<0.05); there was no statistical significant difference in the expression level of PD-L2 molecule of patients between the active group and the RA group (P>0.05); Pearson correlation analysis found that SLEDAI score was positively correlated with PD-L2 molecular expression level of SLE patients (r=0.946, P=0.000); the receiver operating curve was drawn, the results showed that the area under the curve of PD-L2 molecular expression level in the prediction of SLE patients at active stage was 0.820, which had high predictive value. Conclusion The expression level of PD-L2 molecule in PBMC is closely related to the degree of disease activity in SLE patients, which can assist clinical evaluation of the severity of the disease, and provide effective reference for the formulation of clinical treatment regimen.
