Precision diagnosis of lupus nephritis: opportunities and role of biomarkers

The most common complication in patients with systemic lupus erythematosus is lupus nephritis (LN), a condition that can lead to end-stage kidney disease. In recent years, many serum and urine biomarkers, genetic studies have been proposed for the diagnosis of LN, but none of them entered into guidelines for clinical use. The majority of studies have been single-center with significant variability in cohorts, assays, and sample storage, leading to inconclusive results. It has become clear that no single biomarker is likely to be sufficient to diagnose LN, identify flares, and define the response to therapy and prognosis. A more likely scenario for future diagnostics is a panel of biomarkers for urine, serum, kidney tissue, and genetic biomarkers. The review summarizes the data on traditional and new serum, urinary and genetic biomar­kers, discusses the feasibility of their use in clinical practice and the possibility of implementation for a more accurate diagnosis of LN. Each “panel” of biomarkers will provide a unique understanding of the various clinical issues of disease development and progression. Thus, the genetic panel can determine the likelihood of nephritis in a patient with systemic lupus erythematosus and which inflammatory pathways will be involved in the LN development. A urine biomarker panel can help distinguish between inflammation and fibrosis, eliminating the need for repeated biopsies. A serum biomarker panel can identify nephritogenic autoantibodies that increase the number of exacerbations, cause their severity and worsen the response to treatment. A more systematic and focused approach to the study of biomarkers will allow precision diagnosis to become a reality for patients with LN.