<b><i>Introduction:</i></b> While renal biopsy remains the gold standard for diagnosing lupus nephritis (LN), the prognostic and diagnostic role of non-invasive biomarkers for LN is currently debated. <b><i>Methods:</i></b> Available studies published in last 5 years (2015–2020) assessing the diagnostic and prognostic value of urinary and/or serological biomarkers in subjects with LN were analyzed in this systematic review. <b><i>Results:</i></b> Eighty-five studies were included (comprehending 13,496 patients with systemic lupus erythematosus [SLE], 8,872 LN, 487 pediatric LN, 3,977 SLE but no LN, 160 pediatric SLE but no LN and 7,679 controls). Most of the studies were cross-sectional (62; 73%), while 14 (17%) were prospective. In sixty studies (71%), the diagnosis of LN was biopsy-confirmed. Forty-four out of 85 (52%) investigated only serological biomarkers, 29 studies (34%) tested their population only with urinary biomarkers, and 12 (14%) investigated the presence of both. Outcome measures to assess the clinical utility of the analyzed biomarkers were heterogeneous, including up to 21 different activity scores, with the SLEDAI (in 60%) being the most used. Despite some heterogeneity, promising results have been shown for biomarkers such as urinary monocyte chemoattractant protein, urinary adiponectin, and urinary vascular cell adhesion protein 1. <b><i>Discussion/Conclusion:</i></b> While serum and urine biomarkers have the potential to improve diagnostic and prognostic pathways in patients with LN, the vast heterogeneity across studies severely limits their applicability in current clinical practice. With the kidney biopsy still representing the gold standard, future efforts should focus on harmonizing study inclusion criteria and outcomes, particularly in clinical trials, in order to improve comparability and facilitate the implementations of available biomarkers into the daily practice.

Objectives The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in patients with systemic lupus erythematosus (SLE) remains unclear and data on clinical manifestations after infection are lacking. The aim of this multicentre study is to describe the effect of SARS-CoV-2 in SLE patients. Methods SLE patients referring to 4 Italian centres were monitored between February 2020 and March 2021. All patients with SARS-CoV-2 infection were included. Disease characteristics, treatment, disease activity, and SARS-CoV-2 related symptoms were recorded before and after the infection. Results Fifty-one (6.14%) SLE patients were included among 830 regularly followed-up. Nine (17.6%) had an asymptomatic infection. Five (9.8%), out of 42 (82.6%) symptomatic, developed interstitial pneumonia (no identified risk factor). The presence of SLE major organ involvement (particularly renal involvement) was associated with asymptomatic SARS-CoV-2 infection (p-value = 0.02). Chronic corticosteroid therapy was found to be associated with asymptomatic infection (p-value = 0.018). Three SLE flares (5.9%) were developed after SARS-CoV-2 infection: one of them was characterized by MPO-ANCA positive pauci-immune crescentic necrotizing glomerulonephritis and granulomatous pneumonia. Conclusions SARS-CoV-2 infection determined autoimmune flares in a small number of our patients. Our data seem to confirm that there was not an increased risk of SARS-CoV-2 in SLE. Patients with asymptomatic SARS-CoV-2 infections were those having major SLE organ involvement. This may be explained by the high doses of corticosteroids and immunosuppressive agents used for SLE treatment.

Vulnerable subjects, including systemic lupus erythematosus (SLE) patients, have been prioritised to receive anti-SARS-CoV-2 vaccines. Few data about the safety of these vaccines in SLE are available. The aim of our study is to investigate the safety of anti-SARS-CoV-2 vaccines in SLE. We included 452 SLE patients, referring to seven tertiary centres, who were immunised. A total of 119 (26%) reported side effects (SE) after the first and/or the second shot (the most frequent SE were fever, local reaction, fatigue, and arthralgia). Patients with constitutional symptoms and those on an immunosuppressive regimen (especially belimumab) showed more SE. In addition, 19 (4%) had a flare after the immunisation (flares classified by organ involvement: six musculoskeletal with constitutional symptoms, four renal, three cardio-respiratory, three haematological, two mucocutaneous). None of the patients needed hospitalisation and none died. Moreover, 15 required a transient increase in corticosteroids and four were treated with steroid pulses. One patient required an additional rituximab course. Anti-dsDNA, moderate/high DAS before vaccine, and belimumab were found more frequently in patients with disease flare. Anti-SARS-CoV-2 vaccines are safe in SLE patients, and they should be recommended in these patients, as the potential benefits widely outweigh the risk of SE. Treatment adjustment might be considered with the aim of minimising SE risk and flare.