Serum myeloperoxidase level as A marker of activity in patients with systemic lupus erythematosus with lupus nephritis class III and IV

Abstract


Introduction
Systemic lupus erythematosus (SLE) is a chronic, multi-factorial inflammatory autoimmune disease that primarily affects women between the ages of early adulthood and mid-adulthood.It is characterized by the production of a wide range of autoantibodies and immune complex deposition, which can damage multiple organs (1).
The inflow of pro-inflammatory cytokines mediates an inflammatory response.Various acute-phase reactant proteins, such as high sensitivity C-reactive proteins (hs-CRPs), lectin proteins, hepcidin, etc., are produced as a result of these cytokines, and these proteins are recognised as inflammatory indicators (2).In particular, anti-MPO antibodies will be covered.According to one research, SLE or a drug-induced condition that is similar to SLE, drug-induced vasculitis or nephritis, and idiopathic vasculitis are all associated with high titers of anti-MPO antibodies (5).
Anti-MPO antibodies are thought to play a part in processes that activate neutrophils, causing neutrophil extracellular traps (NET) to develop and tissue damage in either druginduced lupus or idiopathic SLE.
Interestingly, a research found that MPO plasma levels were significantly greater in SLE patients than in healthy individuals, despite the fact that this did not correspond with the severity of the condition (6).

Aim of the Study:
This study aimed to assess the serum MPO and assess its correlation with lupus nephritis activity in class III, IV by SLEDAI as disease activity score.

Statistical analysis:
Analysis of data was performed using SPSS

Results:
Table (1) showed that there was no significant difference between cases and controls regarding their age, sex, hypertension and diabetes mellitus distribution.There were no cases of diabetes among both groups.The mean systolic and diastolic blood pressure were significantly higher among cases than controls but both groups were with normotensive blood pressure.showed that the mean Albumin/Creatinine ratio was significantly higher among cases than controls in contrast to the hemoglobin; it was significantly higher among controls than cases.
There was no significant difference between cases and controls regarding the level of Sodium and Potassium, and Creatinine.The mean Anti DNA , ESR, and ANA titer were significantly higher among cases than controls, but C3 and C4 were significantly higher in controls than cases.

Table (2) Laboratory and inflammatory markers distribution among the studied groups:
*P-value is significant This study showed that the mean SLEDAI score was 37.6±14.4and ranged from 14 to 75 with median 40.This table showed that the mean myeloperoxidase marker was significantly higher among cases than controls (Table 3) anti-double stranded DNA antibodies (Anti-dsDNA titer) are used to assess SLE activity in clinical practice (4).https://ejmr.journals.ekb.eg/

v. 25 (
Statistical Package for Social science) for Windows.Description of quantitative variables was in the form of mean, standard deviation (SD), minimum, maximum and median.Description of qualitative variables https://ejmr.journals.ekb.eg/ was in the form of numbers (No.) and percent's (%).Mann-Whitney U test was used to compare between two groups regarding scale variables while independent T test was used to compare between groups regarding normally distributed variables.ROC curve was used to predict optimal cut off in marker and A/C ratio in prediction of SLE nephropathy.Pearson correlation was used to correlate between normally distributed variables.The significance of the results was assessed in the form of P-value that was differentiated into: non-significant when P-value > 0.05 and significant when Pvalue ≤ 0.05 Ethical considerations: The study protocol was approved by the research ethics committee of Faculty of Medicine of Beni-Suef University number FMBSUREC/03012021/Ali.An informed consent was obtained from the participants and all data was anonymous and confidential.

Figure
Figure (1) Receiver Operating Characteristic curve for prediction of lupus nephritis using serum Myeloperoxidase

Special laboratory tests:
Exclusion criteria:Patients less than 16 or older than 45 years with end stage renal disease were excluded.Methods:All patients were subjected to full clinical and laboratory investigations.A sheet was formulated and applied to all patients subjected to this study.Personal history as age, sex., residence and menstrual history.history.https://ejmr.journals.ekb.eg/Radiological Investigations: if indicated in the form of Pelvi abdominal ultrasound.

Table ( 1) Age and sex distribution, comorbidities of medical importance and blood pressure among the studied groups:
*P-value is significant https://ejmr.journals.ekb.eg/Table (2)

Table ( 4) Sensitivity, specificity, PPV and NPV of serum Myeloperoxidase in detection of lupus nephritis compared to A/C ratio:
Table (4) and figure (1,2) showed that the serum myeloperoxidase had a significant role in prediction of lupus nephritis at a cut off more than 178.5, it can predict the LN with 80% sensitivity, 50% specificity, 61.5% PPV and 71.4% NPV.The A/C ratio seemed to be highly predictor for LN than the serum myeloperoxidase as at a cut off more than 30, it can predict the LN with 100% sensitivity, 97.5% specificity, 97.6% PPV and 100% NPV.

Table ( 5
) showed that there was no significant linear correlation between serum level of myeloperoxidase and different parameters except ESR and SLEDAI score, ESR had a moderate linear positive correlation with the marker level.SLEDAI score had a strong positive linear correlation with myeloperoxidase.