Background To assess the value of peptidoglycan recognition protein 2 (PGLYRP2) in assessing the disease activity and lipid metabolism in patients with systemic lupus erythematosus (SLE). Methods SLE patients with stable disease (n = 15), active lupus nephritis (LN) (n = 15) and neuropsychiatric systemic lupus erythematosus (NP-SLE) (n = 15) admitted to Northern Jiangsu People’s Hospital (Jiangsu, China) in 2019–2020 were recruited. In addition, volunteers with matched age and sex (n = 15) were enrolled as controls. The level of PGLYRP2 in the serum and its expression in peripheral blood mononuclear cells (PBMCs) were measured. The link between PGLYRP2 level and clinical parameters (including lipid profile) was described. Results Serum PGLYRP2 level in SLE cases exceeded that in healthy volunteers (3938.56 ± 576.07 pg/mL), and significantly higher in active LN (5152.93 ± 446.13 pg/mL) and NP-SLE patients (5141.52 ± 579.61 pg/mL). As shown by quantitative real-time PCR results, the expression of PGLYRP2 in PBMCs of SLE patients with active LN and NP-SLE surpassed that in healthy volunteers (P < 0.01). Receiver operating characteristic (ROC) curves demonstrated that PGLYRP2 was capable of distinguishing stable SLE from active LN (AUC = 0.841, 95%CI = 0.722–0.960, P = 0.000). PGLYRP2 level positively correlated with SLEDAI of SLE patients (r = 0.5783, P < 0.01). Moreover, its level varied with serological and renal function parameters (complement 3, complement 4, estimated glomerular filtration rate and 24-h urine protein) and immunoglobulin A (IgA) of SLE. A potential correlation between PGLYRP2 level and lipid profile (HLD-c, Apo-A1 and Apo B/A1) was determined in SLE patients. The linear regression analysis indicated SLEDAI as an independent factor of PGLYRP2 level, with a positive correlation in between (P < 0.05). Conclusions Serum PGLYRP2 level significantly increases in SLE patients, and is positively correlated to SLEDAI. Moreover, serum PGLYRP2 level is correlated with renal damage parameters and the abnormal lipid profile of SLE. PGLYRP2 could be used to predict SLE activity, dyslipidemia and cardiovascular disease risks in SLE patients.

Background: Patients with systemic lupus erythematosus (SLE) suffer from a high incidence of premature ovarian failure, which might be due to cyclophosphamide gonadal toxicity, immune abnormalities, or other reasons. This study aimed to investigate whether the transplantation of human umbilical cord mesenchymal stem cells (HUC-MSCs) can improve ovarian reserve function in lupus mice. Methods: We used MRL/lpr mice to observe changes in ovarian structure and secretory function in SLE. Lupus mice and controls were injected with HUC-MSCs at Weeks 12 and 16. We detected serum concentrations of the sex hormones estradiol (E2), follicle-stimulating hormone (FSH), and anti-Müllerian hormone (AMH), using enzyme-linked immunosorbent assays. Hematoxylin and eosin staining showed ovarian tissue structure and enabled the counting of follicles. Hepatocyte growth factor (HGF) and insulin-like growth factor 1 (IGF-1) expression in ovarian tissue was observed by immunohistochemistry.Results: Ovarian function in lupus mice was abnormal, as indicated by decreased serum E2 and AMH concentrations, and increased FSH concentrations. HUC-MSC transplantation caused significant upregulation of serum E2 and AMH and downregulation of FSH (all p < 0.05). Ovarian structure improved and the follicle number increased after HUC-MSC transplantation. Multiple infusions of HUC-MSCs at Weeks 12 and 16 resulted in a significantly higher number of primordial follicles than infusions of HUC-MSCs at only Week 12 (p < 0.05). Immunohistochemistry showed that IGF-1 and HGF expression increased after HUC-MSC transplantation, but this was not significant. Conclusions: HUC-MSCs transplantation restores disturbed hormone secretion and folliculogenesis in lupus mice. HUC-MSC transplantation should be repeated for the best treatment effect. K E Y W O R D S human umbilical cord mesenchymal stem cells, MRL/lpr mice, premature ovarian failure, systemic lupus erythematosus Key points • Ovarian function in lupus mice was abnormal with disturbed hormone secretion and folliculogenesis and human umbilical cord mesenchymal stem cell transplantation could recover ovarian function in lupus mice. • Systemic lupus erythematosus (SLE) itself may have an abnormal ovarian function. We also suggested novel strategies to treat patients with SLE with premature ovarian failure.