Remission of lupus nephritis: the trajectory of histological response in successfully treated patients

Lupus nephritis-related chronic kidney disease

Lupus nephritis is a common complication of systemic lupus erythematosus (SLE) and a determinant of overall morbidity and mortality, as lupus nephritis-related chronic kidney disease (CKD) drives cardiovascular disease and secondary immunodeficiency. Two lines of action are required to prevent the progression of lupus nephritis-related CKD: suppression of autoimmune SLE activity, which is a risk factor for immunopathology-related irreversible kidney injury, and management of non-immune risk factors that contribute to CKD progression. As each episode or relapse of active lupus nephritis implicates CKD progression, preventing flares of lupus nephritis is a key treatment target. Non-immune risk factors of CKD mostly include causes of nephron hyperfiltration, such as obesity, hypertension, sodium- or protein-rich diets and type 2 diabetes mellitus, as well as pregnancy. Nephrotoxic agents and smoking also drive kidney cell loss. Intrinsic risk factors for CKD progression include poor nephron endowment because of prematurity at birth, nephropathic genetic variants, ageing, male sex and previous or concomitant kidney diseases. Care for lupus nephritis involves the control of all modifiable risk factors of CKD progression. In addition, remnant nephron overload can be reduced using early dual therapy with inhibitors of the renin-angiotensin system and sodium-glucose transporter-2, whereas further renoprotective drug interventions are underway. As patients with lupus nephritis are at risk of CKD progression, they would all benefit from interdisciplinary care to minimize the risk of kidney failure, cardiovascular disease and infections.

Kidney Outcomes and Preservation of Kidney Function With Obinutuzumab in Patients With Lupus Nephritis: A Post Hoc Analysis of the NOBILITY Trial

OBJECTIVE

To determine whether adding obinutuzumab to standard-of-care lupus nephritis (LN) therapy could improve the likelihood of long-term preservation of kidney function and do so with less glucocorticoids.

METHODS

Post hoc analyses of the phase II NOBILITY trial were performed. Time to unfavorable kidney outcome (a composite of treatment failure, doubling of serum creatinine, or death), LN flare, first 30% and 40% declines in estimated glomerular filtration rate (eGFR) from baseline, and chronic eGFR slope during the trial were compared between patients with active LN who were randomized to take obinutuzumab (n = 63) or placebo (n = 62) in combination with mycophenolate mofetil and glucocorticoids. The number of patients who achieved complete renal response (CRR) on 7.5 mg or less per day of prednisone was also determined.

RESULTS

Obinutuzumab reduced the risk of developing the composite kidney outcome by 60%, LN flare by 57%, and first eGFR decline of 30% or 40% by 80% and 91%, respectively. Patients receiving obinutuzumab had a significantly slower decline in eGFR than patients receiving placebo, with an annualized eGFR slope advantage of 4.1 ml/min/1.73 m2 /year (95% confidence interval 0.14-8.08). Overall, 38% of patients receiving obinutuzumab compared with 16% of patients receiving placebo achieved CRR at week 76 while receiving 7.5 mg or less per day of prednisone (P < 0.01); at week 104, the difference did not achieve significance (38% vs 22%; P = 0.06).

CONCLUSION

Post hoc analyses of NOBILITY demonstrated that compared with standard-of-care therapy, obinutuzumab treatment resulted in superior preservation of kidney function and prevention of LN flares. More patients achieved CRR at week 76 with less glucocorticoid use in the obinutuzumab group.

Kidney Biopsy in Management of Lupus Nephritis: A Case-Based Narrative Review

Kidney involvement in patients with lupus highly increases morbidity and mortality. In recent years, several reports have emphasized the dissociation between clinical and histological findings and highlighted the role of kidney biopsy as an instrument for diagnosis and follow-up of lupus nephritis. The kidney biopsy at initial diagnosis allows an early diagnosis, assessment of activity and chronicity, and detection of nonimmune complex nephritis. A kidney biopsy repeated months after treatment aids in the detection of persistent histological inflammation, which has been linked to the occurrence of future kidney relapses. A kidney biopsy at a relapse detects histological changes including chronic scarring. Finally, a kidney biopsy in patients with a clinical response undergoing maintenance immunosuppression may aid therapy tapering and/or suspension. The evidence supporting the use of a kidney biopsy in different scenarios across the course of lupus nephritis is heterogeneous, with most reports assessing the value for the diagnosis of a first or relapsing flare. In contrast, less evidence suggests additional therapeutic-modifying information derived from repeat posttreatment biopsies and biopsies to evaluate treatment tapering or suspension. In this clinical case-based review, we examine the role of kidney biopsy as a tool to improve clinical outcomes of patients with lupus nephritis.

Single cell spatial transcriptomic profiling of childhood-onset lupus nephritis reveals complex interactions between kidney stroma and infiltrating immune cells

Children with systemic lupus erythematosus (SLE) are at increased risk of developing kidney disease, termed childhood-onset lupus nephritis (cLN). Single cell transcriptomics of dissociated kidney tissue has advanced our understanding of LN pathogenesis, but loss of spatial resolution prevents interrogation of in situ cellular interactions. Using a technical advance in spatial transcriptomics, we generated a spatially resolved, single cell resolution atlas of kidney tissue (>400,000 cells) from eight cLN patients and two controls. Annotated cells were assigned to 35 reference cell types, including major kidney subsets and infiltrating immune cells. Analysis of spatial distribution demonstrated that individual immune lineages localize to specific regions in cLN kidneys, including myeloid cells trafficking to inflamed glomeruli and B cells clustering within tubulointerstitial immune hotspots. Notably, gene expression varied as a function of tissue location, demonstrating how incorporation of spatial data can provide new insights into the immunopathogenesis of SLE. Alterations in immune phenotypes were accompanied by parallel changes in gene expression by resident kidney stromal cells. However, there was little correlation between histologic scoring of cLN disease activity and glomerular cell transcriptional signatures at the level of individual glomeruli. Finally, we identified modules of spatially-correlated gene expression with predicted roles in induction of inflammation and the development of tubulointerstitial fibrosis. In summary, single cell spatial transcriptomics allows unprecedented insights into the molecular heterogeneity of cLN, paving the way towards more targeted and personalized treatment approaches.