The potential use of serum interleukin-21 as biomarker for lupus nephritis activity compared to cytokines of the tumor necrosis factor (TNF) family

Systemic lupus erythematosus: latest insight into etiopathogenesis

Systemic lupus erythematosus (SLE) is a complex autoimmune disorder of unknown etiology. Multifactorial interaction among various susceptible factors such as environmental, hormonal, and genetic factors makes it more heterogeneous and complex. Genetic and epigenetic modifications have been realized to regulate the immunobiology of lupus through environmental modifications such as diet and nutrition. Although these interactions may vary from population to population, the understanding of these risk factors can enhance the perception of the mechanistic basis of lupus etiology. To recognize the recent advances in lupus, an electronic search was conducted among search engines such as Google Scholar and PubMed, where we found about 30.4% publications of total studies related to genetics and epigenetics, 33.5% publications related to immunobiology and 34% related to environmental factors. These outcomes suggested that management of diet and lifestyle have a direct relationship with the severity of lupus that influence via modulating the complex interaction among genetics and immunobiology. The present review emphasizes the knowledge about the multifactorial interactions between various susceptible factors based on recent advances that will further update the understanding of mechanisms involved in disease pathoetiology. Knowledge of these mechanisms will further assist in the creation of novel diagnostic and therapeutic options.

Relative CTLA-4, PTPN-22, and interleukin 37 mRNA expressions in patients with lupus nephritis

OBJECTIVES

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by T-cell immune-dysregulation and loss of tolerance to self-antigens. CTLA-4 and PTPN-22 are involved in the inhibition of T-lymphocytes activation. IL-37 is an anti-inflammatory cytokine that suppresses innate immunity. The relative expression of CTLA-4, IL-37 and PTPN-22 were evaluated as negative regulators of immune response in SLE patients, lupus nephritis (LN) and disease activity.

METHODS

Real-Time PCR was performed to determine relative CTLA-4, IL-37, and PTPN-22 mRNA expressions in fifty-eight SLE patients, who were divided into two groups: 29 SLE patients without nephritis and 29 patients with LN, versus fifty controls.

RESULTS

There was a significantly high-expression of CTLA-4 and IL-37 genes in SLE patients compared to controls (p=0.005; 0.018 respectively). There was no difference in relative PTPN-22 mRNA expression between the SLE patients and controls. Relative CTLA-4 mRNA expression decreased in LN patients (p=0.044), however, relative IL-37 mRNA over-expressed in LN patients (p=0.001) compared to those without LN. There was a significant over-expression of relative IL-37 andPTPN-22 mRNA in active SLE patients. But, there was a non-significant difference in CTLA-4 expression with disease activity. Regression analysis revealed patients with relative IL-37 mRNA over-expression had two times more to develop lupus nephritis (OR=1.906, 95% CI=1.218-2.983, p=0.005).

CONCLUSIONS

Relative IL-37mRNA expression was elevated in SLE patients and associated with renal involvement and disease activity. It could be considered as a new promising predicting tool for LN. Relative PTPN-22 mRNA expression was correlated with disease activity only in SLE patients.

B-cell activating factor and A proliferation-inducing ligand in relation to intima-media thickness as biomarkers of premature atherosclerosis in systemic lupus erythematosus patients

BACKGROUND

The aim of this study was to assess the correlation of the serum B-cell activating factor (BAFF), A proliferation-inducing ligand (APRIL) and interleukin (IL)-21 with carotid intima-media thickness (cIMT) to evaluate their efficacy as non-invasive biomarkers for the risk of premature development of atherosclerosis.

METHODS

ELISA test was used to quantify serum BAFF, APRIL and IL-21 in 40 patients with systemic lupus erythematosus (SLE) and 20 healthy controls (HCs). The obtained results were correlated with disease duration, anti-double stranded DNA, complement proteins levels, lipid profile, cIMT and the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI).

RESULTS

Serum BAFF, APRIL and IL-21 were significantly increased in SLE compared to HCs. Positive correlation was recorded between BAFF (r = 0.51) and APRIL (r = 0.52) with the cIMT. IL-21 correlated positively with SLEDAI (r = 0.33) and negatively with BAFF (r = -0.37) and APRIL (r = -0.44). According to the multiple logistic regression analysis, we found that low-density lipoprotein, serum BAFF and APRIL values were independent factors for cIMT in SLE. To discriminate premature atherosclerosis in patients with SLE, BAFF ≥455 pg/ml yielded 88.9% sensitivity with 100% specificity while APRIL ≥600 pg/ml yielded 95% sensitivity with 100% specificity. IL-21 ≥240 pg/ml yielded 66.7% sensitivity and 100% specificity.

CONCLUSIONS

Circulating BAFF and APRIL in patients with SLE were correlated to disease activity and cIMT, suggesting that they could be used as a peripheral blood biomarker for the occurrence of premature atherosclerosis in SLE.