Urinary Tumor Necrosis Factor-Like Weak Inducer of Apoptosis as a Biomarker for Diagnosis and Evaluating Activity in Lupus Nephritis: A Meta-analysis

Urinary TWEAK reflects disease activity in ANCA-associated vasculitis

Background

The aim of the study was to investigate urinary and serum tumour necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) as potential biomarkers in a longitudinal cohort of patients with ANCA-associated vasculitis (AAV).

Methods

Patients with active AAV were included in the study. The Birmingham Vasculitis Score 2003 (BVAS) was used for assessment of disease activity and C-reactive protein (CRP), creatinine, albuminuria, and serum (s) and urinary (u) TWEAK levels were measured at baseline and 6-month follow-up. sTWEAK was measured in population-based controls for comparison. Kidney biopsies from AAV patients were stained for TWEAK and its receptor fibroblast growth factor-inducible 14 (Fn14) using immunohistochemistry (IHC).

Results

sTWEAK was measured in 74 patients and uTWEAK in 69 patients, 42 of whom had kidney involvement. uTWEAK-to-creatinine ratio (uTWEAK/Cr) was significantly higher at baseline compared with follow-up (median 7.21 vs 4.94 ng/mmol, P < .0001). Patients with kidney involvement had higher uTWEAK/Cr levels compared with those without (P = .03). A correlation was found between uTWEAK/Cr and BVAS (P = .006), albuminuria (P = .022) and crescentic changes (P = .03). sTWEAK levels were higher in patients at inclusion than at follow-up (P = .009) but no difference was found when comparing patients and controls, nor did sTWEAK correlate with BVAS. IHC staining showed a clear expression of TWEAK but a fainter pattern of Fn14 in kidney biopsies from AAV patients.

Conclusions

uTWEAK/Cr correlated with BVAS, albuminuria and number of crescents in active AAV and may be a useful biomarker in assessing disease activity in patients with AAV, whereas sTWEAK level is not.

Investigating the value of urinary biomarkers in relation to lupus nephritis histopathology: present insights and future prospects

Lupus nephritis (LN), a leading cause of death in Systemic Lupus Erythematosus (SLE) patients, presents significant diagnostic and prognostic challenges. Although renal pathology offers critical insights regarding the diagnosis, classification, and therapy for LN, its clinical utility is constrained by the invasive nature and limited reproducibility of renal biopsies. Moreover, the continuous monitoring of renal pathological changes through repeated biopsies is impractical. Consequently, there is a growing interest in exploring urine as a non-invasive, easily accessible, and dynamic "liquid biopsy" alternative to guide clinical management. This paper examines novel urinary biomarkers from a renal pathology perspective, encompassing cellular components, cytokines, adhesion molecules, auto-antibodies, soluble leukocyte markers, light chain fragments, proteins, small-molecule peptides, metabolomics, urinary exosomes, and ribonucleic acids. We also discuss the application of combined models comprising multiple biomarkers in assessing lupus activity. These innovative biomarkers and models offer insights into LN disease activity, acute and chronic renal indices, fibrosis, thrombotic microangiopathy, podocyte injury, and other pathological changes, potentially improving the diagnosis, management, and prognosis of LN. These urinary biomarkers or combined models may serve as viable alternatives to traditional renal pathology, potentially revolutionizing the method for future LN diagnosis and observation.

Non-Invasive Biomarkers for Diagnosis, Risk Prediction, and Therapy Guidance of Glomerular Kidney Diseases: A Comprehensive Review

Effective management of glomerular kidney disease, one of the main categories of chronic kidney disease (CKD), requires accurate diagnosis, prognosis of progression, assessment of therapeutic efficacy, and, ideally, prediction of drug response. Multiple biomarkers and algorithms for the assessment of specific aspects of glomerular diseases have been reported in the literature. Though, the vast majority of these have not been implemented in clinical practice or are not available on a global scale due to limited access, missing medical infrastructure, or economical as well as political reasons. The aim of this review is to compile all currently available information on the diagnostic, prognostic, and predictive biomarkers currently available for the management of glomerular diseases, and provide guidance on the application of these biomarkers. As a result of the compiled evidence for the different biomarkers available, we present a decision tree for a non-invasive, biomarker-guided diagnostic path. The data currently available demonstrate that for the large majority of patients with glomerular diseases, valid biomarkers are available. However, despite the obvious disadvantages of kidney biopsy, being invasive and not applicable for monitoring, especially in the context of rare CKD etiologies, kidney biopsy still cannot be replaced by non-invasive strategies.

Lupus Nephritis Biomarkers: A Critical Review

Lupus nephritis (LN), a major complication in individuals diagnosed with systemic lupus erythematosus, substantially increases morbidity and mortality. Despite marked improvements in the survival of patients with severe LN over the past 50 years, complete clinical remission after immunosuppressive therapy is achieved in only half of the patients. Therefore, timely detection of LN is vital for initiating prompt therapeutic interventions and improving patient outcomes. Biomarkers have emerged as valuable tools for LN detection and monitoring; however, the complex role of these biomarkers in LN pathogenesis remains unclear. Renal biopsy remains the gold standard for the identification of the histological phenotypes of LN and guides disease management. However, the molecular pathophysiology of specific renal lesions remains poorly understood. In this review, we provide a critical, up-to-date overview of the latest developments in the field of LN biomarkers.