Abnormalities in B cells play pivotal roles in the pathogenesis of systemic lupus erythematosus (SLE) and lupus nephritis (LN). Breach in central and peripheral tolerance mechanisms generates autoreactive B cells which contribute to the pathogenesis of SLE and LN. Dysregulation of B cell transcription factors, cytokines and B cell–T cell interaction can result in aberrant B cell maturation and autoantibody production. These immunological abnormalities also lead to perturbations in circulating and infiltrating B cells in SLE and LN patients. Conventional and novel immunosuppressive medications confer differential effects on B cells which have important clinical implications. While cyclophosphamide and mycophenolate mofetil (MMF) showed comparable clinical efficacy in active LN, MMF induction was associated with earlier reduction in circulating plasmablasts and plasma cells. Accumulating evidence suggests that MMF maintenance is associated with lower risk of disease relapse than azathioprine, which may be explained by its more potent and selective suppression of B cell proliferation. Novel therapeutic approaches targeting the B cell repertoire include B cell depletion with monoclonal antibodies binding to cell surface markers, inhibition of B cell cytokines, and modulation of costimulatory signals in B cell–T cell interaction. These biologics, despite showing improvements in serological parameters and proteinuria, did not achieve primary endpoints when used as add-on therapy to standard treatments in active LN patients. Other emerging treatments such as calcineurin inhibitors, mammalian target of rapamycin inhibitors and proteasome inhibitors also show distinct inhibitory effects on the B cell repertoire. Advancement in the knowledge on B cell biology has fueled the development of new therapeutic strategies in SLE and LN. Modification in background treatments, study endpoints and selective recruitment of subjects showing aberrant B cells or its signaling pathways when designing future clinical trials may better elucidate the roles of these novel therapies for SLE and LN patients.

Renal anaemia is a common and important complication in patients with chronic kidney disease (CKD). The current standard‐of‐care treatment for renal anaemia in CKD patients involves ensuring adequate iron stores and administration of erythropoietin stimulating agents (ESA). Hypoxia inducible factor (HIF) is a key transcription factor primarily involved in the cellular regulation and efficiency of oxygen delivery. Manipulation of the HIF pathway by the use of HIF‐prolyl hydroxylase inhibitors (HIF‐PHI) has emerged as a novel approach for renal anaemia management. Despite it being approved for clinical use in various Asia‐Pacific countries, its novelty mandates the need for nephrologists and clinicians generally in the region to well understand potential benefits and harms when prescribing this class of drug. The Asian Pacific society of nephrology HIF‐PHI Recommendation Committee, formed by a panel of 11 nephrologists from the Asia‐Pacific region who have clinical experience or have been investigators in HIF‐PHI studies, reviewed and deliberated on the clinical and preclinical data concerning HIF‐PHI. This recommendation summarizes the consensus views of the committee regarding the use of HIF‐PHI, taking into account both available data and expert opinion in areas where evidence remains scarce.

Objective.: To expand the limited longterm data on sirolimus treatment in patients with lupus nephritis (LN). Our pilot short-term data suggested efficacy of sirolimus treatment in these patients.Methods.: We retrospectively reviewed 16 class III/IV/V patients with LN who have received prednisolone (PSL) and sirolimus either as initial or maintenance treatment.Results.: Sixteen patients received sirolimus treatment (9 because of intolerance to standard immunosuppressants and 7 because of a history of malignancy) for 45.3 ± 36.5 months. In 5 patients, sirolimus and PSL were given as induction for active nephritis, and they showed improvements in proteinuria (2.8 ± 1.9 g/day at baseline, 0.1 ± 0.1 g/day after 36 mos, p = 0.011), anti-dsDNA (107.7 ± 91.9 IU/ml and 37.0 ± 55.4 IU/ml, respectively, p = 0.178), and C3 (54.8 ± 26.1 mg/dl and 86.3 ± 18.6 mg/dl, respectively, p = 0.081). Eleven patients received sirolimus and low-dose PSL as longterm maintenance, and they showed continued improvement in C3 (90.4 ± 18.1 mg/dl and 117.7 ± 25.1 mg/dl at commencement and after 36 mos, respectively, p = 0.025), stable renal function (estimated glomerular filtration rate 58.6 ± 25.8 ml/min and 63.0 ± 29.6 ml/min, respectively, p = 0.239), and proteinuria (0.8 ± 0.7 g/day and 0.7 ± 0.7 g/day respectively, p = 0.252). Renal flare occurred in 1 patient, and another patient who had stage 4 chronic kidney disease when sirolimus was started developed endstage renal failure after 27 months. Sirolimus was discontinued in 5 patients, in 4 cases related to drug side effects. Deterioration of dyslipidemia occurred in 4 patients, but was adequately controlled with statin therapy.Conclusion.: The preliminary evidence suggests that sirolimus may serve as an alternative treatment for patients with LN who do not tolerate standard treatment or who had a history of malignancy, and it has an acceptable longterm safety profile.

Introduction: It remains unclear how the presence of renal involvement will affect the cardiovascular (CV) risk factors and complications in patients with SLE. Methods: We conducted a systematic review and meta-analysis using PubMed, EMBASE, MEDLINE and Scopus to identify studies published between 1947 and 2022 that evaluate the CV risk factors and complications in patients with SLE with or without lupus nephritis (LN). Results: 58 studies were evaluated, with 22 two-arm studies (n=8675) included in two-arm meta-analysis and 45 studies (n=385 315) included in proportional meta-analysis. Patients with SLE with LN showed significantly higher risk of hypertension (HT) (OR=4.93, 95% CI=3.17 to 7.65, p<0.00001, I²=56%), hyperlipidaemia (OR=11.03, 95% CI=4.20 to 28.95, p<0.00001, I²=0%) and diabetes mellitus (DM) (OR=1.88, 95% CI=1.09 to 3.25, p=0.02, I²=32%) compared with those without LN. Patients with LN showed numerically higher prevalence of myocardial infarction (OR=1.35, 95% CI=0.53 to 3.45, p=0.52, I²=78%) and cerebrovascular accident (OR=1.64, 95% CI=0.79 to 3.39, p=0.27, I²=23%) than general patients with SLE. The incidence rates of CV mortality are also increased in patients with SLE with LN compared with those without LN (11.7/1000 patient-years vs 3.6/1000 patient-years). Conclusion: Patients with SLE with LN show increased risk of CV risk factors including DM, HT and hyperlipidaemia. Early identification and optimal control of these CV risk factors may reduce the risk of CV disease and other non-CV complications. PROSPERO registration number: CRD42022314682.

The efficacy and safety of rituximab in childhood steroid-resistant nephrotic syndrome (SRNS) remains unclear. Therefore, we conducted a retrospective cohort study at 28 pediatric nephrology centers from 19 countries in Asia, Europe, North America and Oceania to evaluate this. Children with SRNS treated with rituximab were analyzed according to the duration of calcineurin inhibitors (CNIs) treatment before rituximab [6 months or more (CNI-resistant) and under 6 months]. Primary outcome was complete/partial remission (CR/PR) as defined by IPNA/KDIGO guidelines. Secondary outcomes included kidney failure and adverse events. Two-hundred-forty-six children (mean age, 6.9 years; 136 boys; 57% focal segmental glomerulosclerosis, FSGS) were followed a median of 32.4 months after rituximab. All patients were in non-remission before rituximab. (146 and 100 children received CNIs for 6 month or more or under 6 months before rituximab, respectively). In patients with CNI-resistant SRNS, the remission rates (CR/PR) at 3-, 6-, 12- and 24-months were 26% (95% confidence interval 19.3-34.1), 35.6% (28.0-44.0), 35.1% (27.2-43.8) and 39.1% (29.2-49.9), respectively. Twenty-five patients were in PR at 12-months, of which 22 had over 50% reduction in proteinuria from baseline. The remission rates among children treated with CNIs under 6 months before rituximab were 42% (32.3-52.3), 52% (41.8-62.0), 54% (44.3-64.5) and 60% (47.6-71.3) at 3-, 6-, 12-, and 24-months. Upon Kaplan-Meier analysis, non-remission and PR at 12-months after rituximab, compared to CR, were associated with significantly worse kidney survival Adverse events occurred in 30.5% and most were mild. Thus, rituximab enhances remission in a subset of children with SRNS, is generally safe and CR following rituximab is associated with favorable kidney outcome.

MicroRNAs (miRs) are non-coding small RNAs that act as epigenetic modulators to regulate the protein levels of target mRNAs without modifying the genetic sequences. The role of miRs in the pathogenesis of lupus nephritis (LN) is increasingly recognized and highly complex. Altered levels of different miRs are observed in the blood, urine and kidney tissues of murine LN models and LN patients. Accumulating evidence suggests that these miRs can modulate immune cells and various key inflammatory pathways, and their perturbations contribute to the aberrant immune response in LN. The dysregulation of miRs in different resident renal cells and urinary exosomes can also lead to abnormal renal cell proliferation, inflammation and kidney fibrosis in LN. While miRs may hold promise in various clinical applications in LN patients, there are still many potential limitations and safety concerns for their use. Further studies are worthwhile to examine the clinical utility of miRs in the diagnosis, disease activity monitoring, prognostication and treatment of LN.