Impact of baseline proteinuria level on long-term outcomes in lupus nephritis.

OBJECTIVES: Proteinuria is a marker of lupus nephritis (LN) activity and damage. We aimed to explore the impact of baseline proteinuria level on long-term outcomes. METHODS: We included 249 patients diagnosed with their first biopsy-proven LN. We divided patients based on baseline proteinuria into low-level (≤1 g/day, group 1; 62 patients), moderate-level (>1 and <3 g/day, group 2; 90 patients), and high-level proteinuria (≥3 g/day, group 3; 97 patients). Outcomes included complete proteinuria recovery (CPR) at 1 year, an adverse composite outcome (ESKD, a sustained ≥40% decline in eGFR, or death), and LN flares. Cox proportional hazard models were used to examine the association between baseline characteristics and long-term outcomes. RESULTS: At baseline, the median [IQR] age was 33.2 [26.4, 42.4] years; median proteinuria level was 2.2 [1.0, 3.8] g/day. 177 (71%) patients had proliferative lesions on biopsy; 59.7% in group 1, 78.9% in group 2, and 71.4% in group 3.The rate of achievement of CPR at 1 year was highest for group 1 and lowest for group 3. For long-term outcomes (median follow-up 8.4 years), the frequency of the adverse composite outcome was 27.4%, 26.7%, and 48.5% in groups 1, 2, and 3, respectively; p= 0.003. The corresponding frequency of flares was 27.4%, 38.2%, and 61.9%, respectively; p< 0.001. In the multivariable model for factors associated with long-term outcomes, there was no significant difference between groups 1 and 2; group 3 was associated with the worst prognosis. CONCLUSIONS: Low-level proteinuria is commonly associated with proliferative LN and adverse long-term outcomes.

Short and Long-Term Outcomes of Patients with Pure Membranous Lupus Nephritis Compared to Patients with Proliferative Disease.

OBJECTIVES: Membranous lupus nephritis (MLN) is thought to have a more benign course than proliferative lupus nephritis (PLN). We aimed to determine the differences in short and long-term outcomes between patients with MLN and PLN. METHODS: We included patients with first biopsy-proven MLN and PLN. Short-term outcomes included complete proteinuria recovery (CPR), complete renal response (CRR), and primary efficacy renal response (PERR). Long-term outcomes included a sustained ≥40% reduction in baseline estimated glomerular filtration rate (eGFR), end-stage kidney disease (ESKD), cardiovascular (CV) events, ≥2 increase in SDI, and death. Univariable and multivariable Cox proportional hazard models were used to examine the effect of baseline characteristics on long-term outcomes. RESULTS: Of 215 patients, 51 had pure MLN, and 164 had PLN. We found no significant differences between the two groups in achieving CPR, CRR, and PERR at 1 and 2 years. Median time to outcomes was slightly, but insignificantly, longer in the MLN group.For long-term outcomes, PLN was associated with worse renal and non-renal outcomes, but this was not statistically significant.In the multivariable Cox proportional hazard models, ESKD was associated with the following baseline variables: younger age (HR 0.92, 95% CI 0.87-0.97), higher creatinine (HR 1.01, 95% CI 1.01-1.02), low complement (HR 4.0, 95% CI 1.04-11.10), and higher chronicity index (HR 1.28, 95% CI 1.08-1.51). CONCLUSION: The resolution of proteinuria in LN is slow. MLN is not a benign disease and may be associated with deterioration of renal function, ESKD, damage, CV events, and death.

New EULAR/ACR 2019 SLE Classification Criteria: defining ominosity in SLE.

OBJECTIVE: To determine the ominosity of the European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) Systemic Lupus Erythematosus Classification Criteria by determining its predictive role for disease severity in the first 5 years following diagnosis. METHODS: 867 patients with systemic lupus erythematosus (SLE) from the Toronto Lupus Clinic were included (all first 12 months after SLE diagnosis). The EULAR/ACR criteria score was calculated based on baseline information. To determine disease severity in the first 5 years after diagnosis, adjusted mean SLE Disease Activity Index 2000 (AMS), flares, remission and immunosuppressive treatment were used as outcomes. The Systemic Lupus International Collaborating Clinics (SLICC) registry comprised the validation cohort. RESULTS: Based on receiver operating characteristic analysis, a EULAR/ACR score of 20 was used as a threshold to compare outcomes between groups. In the first 5 years of disease course, patients with a score of ≥20 had higher AMS scores (p<0.001) and were more likely to ever experience a flare (p<0.001). These patients had lower probabilities of achieving remission and higher requirements for immunosuppressives. Results were confirmed in the SLICC validation cohort. Patients with a score of ≥20 had higher AMS during the first 5 years of disease (5.4 vs 3.1% and ≥20 vs <20 respectively, p≤0.001). The score correlated with AMS (r=0.43, p≤0.001) in the same time frame. CONCLUSION: A EULAR/ACR score of ≥20 is an indicator of ominosity in SLE. Patients with a score of ≥20 were characterised by a more active disease course throughout the first 5 years. These criteria provide prognostic information regarding disease severity in the first 5 years following diagnosis.

Urine Extracellular Vesicles Size Subsets as Lupus Nephritis Biomarkers.

Systemic lupus erythematosus (SLE) is an autoimmune disorder that often leads to kidney injury, known as lupus nephritis (LN). Although renal biopsy is the primary way to diagnose LN, it is invasive and not practical for regular monitoring. As an alternative, several groups have proposed urinary extracellular vesicles (uEVs) as potential biomarkers for LN, as recent studies have shown their significance in reflecting kidney-related diseases. As a result, we developed a flow cytometry approach that allowed us to determine that LN patients exhibited a significantly higher total uEV concentration compared to SLE patients without kidney involvement. Additionally, an analysis of different-sized uEV subsets revealed that microvesicles ranging from 0.3 to 0.5 µm showed the most promise for distinguishing LN. These findings indicate that evaluating uEV concentration and size distribution could be a valuable diagnostic and monitoring tool for LN, pending further validation in more comprehensive studies.

CD11c+ T-bet+ CD21hi B Cells Are Negatively Associated With Renal Impairment in Systemic Lupus Erythematosus and Act as a Marker for Nephritis Remission.

Lupus nephritis (LN) is one of the most common manifestations of systemic lupus erythematosus (SLE), characterized by abnormal B cell activation and differentiation to memory or plasma effector cells. However, the role of these cells in the pathogenesis of LN is not fully understood, as well as the effect of induction therapy on B cell subsets, possibly associated with this manifestation, like aged-associated B cells (ABCs). Consequently, we analyzed the molecules defining the ABCs subpopulation (CD11c, T-bet, and CD21) through flow cytometry of blood samples from patients with lupus presenting or not LN, following up a small sub-cohort after six months of induction therapy. The frequency of ABCs resulted higher in LN patients compared to healthy subjects. Unexpectedly, we identified a robust reduction of a CD21hi subset that was almost specific to LN patients. Moreover, several clinical and laboratory lupus features showed strong and significant correlations with this undefined B cell subpopulation. Finally, it was observed that the induction therapy affected not only the frequencies of ABCs and CD21hi subsets but also the phenotype of the CD21hi subset that expressed a higher density of CXCR5. Collectively, our results suggest that ABCs, and more importantly the CD21hi subset, may work to assess therapeutic response since the reduced frequency of CD21hi cells could be associated with the onset of LN.