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.

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.