Caroline J. Poulton

Decreased CD5+ B Cells in Active ANCA Vasculitis and Relapse after Rituximab

BACKGROUND AND OBJECTIVES B cell significance in ANCA disease pathogenesis is underscored by the finding that ANCA alone can cause disease in mouse models and by the effectiveness of rituximab as therapy in ANCA-small vessel vasculitis (ANCA-SVV). To avoid infections and adverse events from therapy, clinicians require improved markers of disease activity and impending relapse to guide immunosuppression strategies after rituximab treatment. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS The B cell phenotype was investigated in patients with active ANCA-SVV and in remission. From 2003 to 2009, 54 patients were followed longitudinally for 4-99 months and compared with 68 healthy controls. In a subset of 19 patients, the B cell immunophenotype was examined in samples after rituximab therapy. RESULTS Patients with active ANCA-SVV had lower %CD5(+) B cells, whereas %CD5(+) B cells from patients in remission were indistinguishable from healthy controls. After rituximab, median time to relapse was 31 months in patients maintaining normalized %CD5(+) B cells, with or without maintenance immunosuppression. Among patients whose B cells repopulated with low %CD5(+) B cells or had a sharply declining %CD5(+) B cells, those who were on low or no maintenance immunosuppression relapsed sooner (median 17 months) than patients who were maintained on high levels of oral maintenance immunosuppression (29 months; P=0.002). CONCLUSIONS The %CD5(+) B cells, as a component of the human B regulatory cell phenotype, is a useful indicator of disease activity, remission, and future relapse, and thus may guide remission maintenance therapy after rituximab treatment.

Personalized prophylactic anticoagulation decision analysis in patients with membranous nephropathy

Primary membranous nephropathy is associated with increased risk of venous thromboembolic events, which are inversely correlated with serum albumin levels. To evaluate the potential benefit of prophylactic anticoagulation (venous thromboembolic events prevented) relative to the risk (major bleeds), we constructed a Markov decision model. The venous thromboembolic event risk according to serum albumin was obtained from an inception cohort of 898 patients with primary membranous nephropathy. Risk estimates of hemorrhage were obtained from a systematic literature review. Benefit-to-risk ratios were predicted according to bleeding risk and serum albumin. This ratio increased with worsening hypoalbuminemia from 4.5:1 for an albumin under 3 g/dl to 13.1:1 for an albumin under 2 g/dl in patients at low bleeding risk. Patients at intermediate bleeding risk with an albumin under 2 g/dl have a moderately favorable benefit-to-risk ratio (under 5:1). Patients at high bleeding risk are unlikely to benefit from prophylactic anticoagulation regardless of albuminemia. Probabilistic sensitivity analysis, to account for uncertainty in risk estimates, confirmed these trends. From these data, we constructed a tool to estimate the likelihood of benefit based on an individuals bleeding risk profile, serum albumin level, and acceptable benefit-to-risk ratio (www.gntools.com). This tool provides an approach to the decision of prophylactic anticoagulation personalized to the individuals needs and adaptable to dynamic changes in health status and risk profile.

Adverse events and infectious burden, microbes and temporal outline from immunosuppressive therapy in antineutrophil cytoplasmic antibody-associated vasculitis with native renal function

BACKGROUND Disease control in anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV) with immunosuppression is effective but burdened by adverse events, especially infections. The study goal was to evaluate risks and types of infections in patients with AAV. METHODS Biopsy-proven AAV patients (diagnosed 1/1991-6/2011) followed in an inception cohort were evaluated for adverse events. Severe infections (requiring intravenous antibiotics, intensive care unit, or causing death) were recorded. Infection number was grouped as none, 1-2 or ≥3. Cox regression was used to estimate hazard ratios with 95% confidence intervals. RESULTS A total of 489 patients (median age 59; 47% female, 55% myeloperoxidase-ANCA) were followed for 2.8 years (median). At 1, 2 and 5 years cumulative incidence of infection was 51, 58 and 65% and severe infection was 22, 23 and 26%. Pulmonary and upper respiratory infections were most common (42 and 30% ever experienced each, respectively), highest in the first 3 months. Staphylococcus aureus was most frequently seen among positive cultures (41%, 78 S. aureus/192 total positive cultures), and only one Pneumocystis jiroveci pneumonia (6 weeks into treatment). All-cause death in 12 months was associated with infections (% deaths: 0 infections 3%; 1-2 infections 10%, ≥3 infections 13%, P = 0.002). Controlling for age, sex and kidney function, patients with severe infections were 4.2 times more likely to die within 12 months (95% CI 2.0-8.7; P = 0.001). CONCLUSIONS More infections increase the risk of a severe infection which increases risk of all-cause mortality. Respiratory and S. aureus infections are dominant. Targeted prophylactic therapy could decrease morbidity.

Trends in Long-Term Outcomes Among Patients With Antineutrophil Cytoplasmic Antibody–Associated Vasculitis With Renal Disease

It is still not clear how advances in the management of antineutrophil cytoplasmic antibody (ANCA)–associated vasculitis (AAV) have impacted long‐term outcomes. We undertook this study to examine changes over 25 years in long‐term clinical outcomes, including the impact of renal function at diagnosis (a potential marker of time to disease detection) and the duration of cyclophosphamide use in AAV patients with renal involvement.

Reduced CD5+CD24hiCD38hi and interleukin-10+ regulatory B cells in active anti-neutrophil cytoplasmic autoantibody-associated vasculitis permit increased circulating autoantibodies

Pathogenesis of anti‐neutrophil cytoplasmic autoantibody (ANCA)‐associated vasculitis is B cell‐dependent, although how particular B cell subsets modulate immunopathogenesis remains unknown. Although their phenotype remains controversial, regulatory B cells (Bregs), play a role in immunological tolerance via interleukin (IL)‐10. Putative CD19+CD24hiCD38hi and CD19+CD24hiCD27+ Bregs were evaluated in addition to their CD5+ subsets in 69 patients with ANCA‐associated vasculitis (AAV). B cell IL‐10 was verified by flow cytometry following culture with CD40 ligand and cytosine–phosphate–guanosine (CpG) DNA. Patients with active disease had decreased levels of CD5+CD24hiCD38hi B cells and IL‐10+ B cells compared to patients in remission and healthy controls (HCs). As IL‐10+ and CD5+CD24hiCD38hi B cells normalized in remission within an individual, ANCA titres decreased. The CD5+ subset of CD24hiCD38hi B cells decreases in active disease and rebounds during remission similarly to IL‐10‐producing B cells. Moreover, CD5+ B cells are enriched in the ability to produce IL‐10 compared to CD5neg B cells. Together these results suggest that CD5 may identify functional IL‐10‐producing Bregs. The malfunction of Bregs during active disease due to reduced IL‐10 expression may thus permit ANCA production.

Podocyte-associated gene mutation screening in a heterogeneous cohort of patients with sporadic focal segmental glomerulosclerosis

BACKGROUND The utility of genetic testing in sporadic focal segmental glomerulosclerosis (FSGS) is unclear. We sought to determine the frequency of podocyte-related gene mutations in a heterogeneous population of adults and children with biopsy-proven FSGS. METHODS The prevalence of pathogenic mutations in five genes (NPHS2, TRPC6, ACTN4, INF2 and PLCE1) and of APOL1 risk alleles (G1 and G2) was ascertained in children and adults diagnosed between 1984 and 2011 with FSGS by renal biopsy. Clinical data were extracted from medical records. RESULTS A total of 65 patients (28 children, 37 adults) with sporadic FSGS were identified (34 females, 31 males), with a mean age of 25 ± 16 years (range from 3 to 62 years). The majority of patients were African American (39 African American, 21 White and 2 Hispanic). We identified biallelic pathogenic NPHS2 mutations in 2 of 28 (7.1%) children, both of whom were of non-Hispanic Caucasian background. A homozygous NPHS2 p.R138Q/p.R138Q mutation was detected in a 5-year-old Caucasian female. Two compound heterozygous NPHS2 mutations p.R138Q/p.R229Q were identified in a 7-year-old Caucasian male patient. One novel, potentially pathogenic non-synonymous variant in INF2 was identified in an African American patient. The proportion of African Americans with two APOL1 risk alleles was 69.2%. CONCLUSIONS This study delineates a role for genetic testing for NPHS2 in children with biopsy-proven sporadic FSGS. Further studies which specify clinical and pathological details of patients will help further define whether there are specific populations that warrant systematic testing of other podocyte-related genes in sporadic FSGS.

Temporal and Demographic Trends in Glomerular Disease Epidemiology in the Southeastern United States, 1986–2015

BACKGROUND AND OBJECTIVES Large-scale, contemporary studies exploring glomerular disease epidemiology in the United States are lacking. We aimed to determine 30-year temporal and demographic trends in renal biopsy glomerular disease diagnosis frequencies in the southeastern United States. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS In this cross-sectional, observational study, we identified all patients with a native kidney biopsy specimen showing one of 18 widely recognized glomerular disease diagnoses referred to the University of North Carolina Chapel Hill Division of Nephropathology between 1986 and 2015. Biopsy era (1986-1995, 1996-2005, and 2006-2015) and demographics (age, sex, and race) were our primary and secondary predictors, respectively, and the relative frequency of each glomerular disease diagnosis was our primary outcome. RESULTS Among 21,374 patients (mean age =48.3±18.3 years old; 50.8% men; 56.8% white; 38.3% black; 2.8% Latino; 1.4% Asian; 0.8% other), the frequency of diabetic glomerulosclerosis in renal biopsy specimens increased dramatically over the three decades (5.5%, 11.4%, and 19.1% of diagnoses, respectively; P for trend <0.001). The frequency of FSGS initially increased but then declined (22.6%, 27.2%, and 24.7%, respectively; P for trend =0.64). The frequencies of other common glomerular disease subtypes remained stable (IgA nephropathy and ANCA/pauci-immune GN) or declined (minimal change disease, membranous nephropathy, membranoproliferative GN, and lupus nephritis). These temporal trends were largely preserved within all demographic subgroups, although cross-sectional frequency distributions differed according to age, sex, and race. CONCLUSIONS We identified significant changes in relative renal biopsy frequencies of many glomerular disease subtypes over three decades. Temporal trends were consistently observed within all major demographic groups, although relative predominance of individual glomerular disease subtypes differed according to patient age, sex, and race. We propose that exploration of behavioral and environmental exposures that likely underlie these findings should be the focus of future hypothesis-driven research.

Trends in long‐term outcomes among patients with ANCA‐associated vasculitis with renal disease

It is still not clear how advances in the management of antineutrophil cytoplasmic antibody (ANCA)–associated vasculitis (AAV) have impacted long‐term outcomes. We undertook this study to examine changes over 25 years in long‐term clinical outcomes, including the impact of renal function at diagnosis (a potential marker of time to disease detection) and the duration of cyclophosphamide use in AAV patients with renal involvement.

Patients with primary membranous nephropathy are at high risk of cardiovascular events

Here we conducted a retrospective study to examine the risk of cardiovascular events (CVEs) relative to that of end-stage renal disease (ESRD) in patients with primary membranous nephropathy, in a discovery cohort of 404 patients. The cumulative incidence of CVEs was estimated in the setting of the competing risk of ESRD with risk factors for CVEs assessed by multivariable survival analysis. The observed cumulative incidences of CVEs were 4.4%, 5.4%, 8.2%, and 8.8% at 1, 2, 3, and 5 years respectively in the primary membranous nephropathy cohort. In the first 2 years after diagnosis, the risk for CVEs was similar to that of ESRD in the entire cohort, but exceeded it among patients with preserved renal function. Accounting for traditional risk factors and renal function, the severity of nephrosis at the time of the event (hazard ratio 2.1, 95% confidence interval 1.1 to 4.3) was a significant independent risk factor of CVEs. The incidence and risk factors of CVEs were affirmed in an external validation cohort of 557 patients with primary membranous nephropathy. Thus early in the course of disease, patients with primary membranous nephropathy have an increased risk of CVEs commensurate to, or exceeding that of ESRD. Hence, reduction of CVEs should be considered as a therapeutic outcome measure and focus of intervention in primary membranous nephropathy.

Treatment with Glucocorticoids or Calcineurin Inhibitors in Primary FSGS

BACKGROUND AND OBJECTIVES In primary FSGS, calcineurin inhibitors have primarily been studied in patients deemed resistant to glucocorticoid therapy. Few data are available about their use early in the treatment of FSGS. We sought to estimate the association between choice of therapy and ESRD in primary FSGS. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS We used an inception cohort of patients diagnosed with primary FSGS by kidney biopsy between 1980 and 2012. Factors associated with initiation of therapy were identified using logistic regression. Time-dependent Cox models were performed to compare time to ESRD between different therapies. RESULTS In total, 458 patients were studied (173 treated with glucocorticoids alone, 90 treated with calcineurin inhibitors with or without glucocorticoids, 12 treated with other agents, and 183 not treated with immunosuppressives). Tip lesion variant, absence of severe renal dysfunction (eGFR≥30 ml/min per 1.73 m(2)), and hypoalbuminemia were associated with a higher likelihood of exposure to any immunosuppressive therapy. Only tip lesion was associated with initiation of glucocorticoids alone over calcineurin inhibitors. With adjusted Cox regression, immunosuppressive therapy with glucocorticoids and/or calcineurin inhibitors was associated with better renal survival than no immunosuppression (hazard ratio, 0.49; 95% confidence interval, 0.28 to 0.86). Calcineurin inhibitors with or without glucocorticoids were not significantly associated with a lower likelihood of ESRD compared with glucocorticoids alone (hazard ratio, 0.42; 95% confidence interval, 0.15 to 1.18). CONCLUSIONS The use of immunosuppressive therapy with calcineurin inhibitors and/or glucocorticoids as part of the early immunosuppressive regimen in primary FSGS was associated with improved renal outcome, but the superiority of calcineurin inhibitors over glucocorticoids alone remained unproven.