Studies on Lupus Nephritis

Systemic Lupus Erythematosus (SLE) is a chronic inflammatory autoimmune disease characterized by multiple organ involvement, production of autoantibodies to nuclear components and local formation or deposition of immune complexes in different organs. Lupus nephritis (LN) is a common and severe manifestation of SLE. A renal biopsy is the “gold standard” for diagnosis of LN and the basis for treatment strategies. However there is no consensus whether a repeat biopsy should be performed to define response to treatment. Biomarkers available for renal disease activity are insufficient and LN patients may have inflammatory lesions in renal tissue despite of clinical quiescent disease. The aim of this thesis was to study clinical, laboratory and histopathological findings in LN-patients with repeated renal biopsies performed after immunosuppressive treatment. I aimed to investigate the role of second renal biopsies in evaluation of treatment response, and to identify novel biomarkers for renal disease activity. We also studied long-term outcome and predictors of response in a subset of patients with severe LN who were treated with B-cell depletion therapy (rituximab). In paper I we studied renal expression and serum levels of High Mobility Group Box 1 protein (HMGB1), a nuclear protein that can act as a proinflammatory mediator and is proposed to be involved in multiple inflammatory diseases. We found high serum levels and increased expression in renal tissue of HMGB1 in LN at both active disease and after immunosuppressive treatment. The study indicates a role for HMGB1 in LN and also supports previous findings of persistent inflammation in the renal tissue despite treatment. In paper II we compared clinical and histopathological findings in LN patients with repeated renal biopsies performed after induction immunosuppressive treatment. A substantial proportion of patients had persistent inflammatory lesions in renal tissue despite an apparent clinical good response. Repeated biopsies may thus add important information that is not captured by routine laboratory markers which in turn may have impact on long-term renal outcome. In paper III we studied serum cytokines in association to clinical and histopathological response in LN. We found high baseline levels of interleukin (IL)-17 in patients with a poor histopathological outcome and high IL-23 in clinical non-responding patients. Immunostainings revealed increased expression of IL-17 in areas with inflammatory CD3+ T-cell infiltrates in renal tissue. The study indicates a Th-17 phenotype in a subset of patients with severe LN. In paper IV we studied long-term (mean 36 months) renal outcome in 25 patients, with previously refractory or relapsing LN, who had been treated with rituximab (RTX). A majority of the patients achieved a complete remission. A long time of B-cell depletion was associated with a faster response. The study supports the use of RTX in patients with refractory LN. In conclusion, repeated renal biopsies after induction treatment revealed persisting active nephritis in many patients despite clinically inactive disease. Consistently, HMGB1 was increased in renal tissue at both active disease and after treatment. A subset of patients with severe LN had high levels of Th-17 associated cytokines which may be of use as biomarkers. LN patients refractory to standard therapy had overall good response at long term follow-up after B-cell depleting therapy

Serum levels of autoantibodies against C-reactive protein correlate with renal disease activity and response to therapy in lupus nephritis

Introduction Serum levels of C-reactive protein (CRP) seldom reflect disease activity in systemic lupus erythematosus (SLE). We have previously shown that autoantibodies against neo-epitopes of CRP often occur in SLE, but that this does not explain the modest CRP response seen in flares. However, we have repeatedly found that anti-CRP levels parallel lupus disease activity, with highest levels in patients with renal involvement; thus, we aimed to study anti-CRP in a material of well-characterized lupus nephritis patients. Methods Thirty-eight patients with lupus nephritis were included. Treatment with corticosteroids combined with cyclophosphamide, mycophenolate mofetil or rituximab was started after baseline kidney biopsy. A second biopsy was taken after ≥ 6 months. Serum creatinine, cystatin C, complement, anti-dsDNA, anti-CRP and urinalysis were done on both occasions. Biopsies were evaluated regarding World Health Organisation (WHO) class and indices of activity and chronicity. Renal disease activity was estimated using the British Isles Lupus Assessment Group (BILAG) index. Results At baseline, 34/38 patients had renal BILAG-A; 4/38 had BILAG-B. Baseline biopsies showed WHO class III (n = 8), IV (n = 19), III to IV/V (n = 3) or V (n = 8) nephritis. Seventeen out of 38 patients were anti-CRP-positive at baseline, and six at follow-up. Overall, anti-CRP levels had dropped at follow-up (P < 0.0001) and anti-CRP levels correlated with renal BILAG (r = 0.29, P = 0.012). A positive anti-CRP test at baseline was superior to anti-dsDNA and C1q in predicting poor response to therapy as judged by renal BILAG. Baseline anti-CRP levels correlated with renal biopsy activity (r = 0.33, P = 0.045), but not with chronicity index. Anti-CRP levels were positively correlated with anti-dsDNA (fluorescence-enhanced immunoassay: r = 0.63, P = 0.0003; Crithidia luciliae immunofluorescence microscopy test: r = 0.44, P < 0.0001), and inversely with C3 (r = 0.35, P = 0.007) and C4 (r = 0.29, P = 0.02), but not with C1q (r = 0.14, P = 0.24). No associations with urinary components, creatinine, cystatin C or the glomerular filtration rate were found. Conclusions In the present study, we demonstrate a statistically significant correlation between anti-CRP levels and histopathological activity in lupus nephritis, whereas a baseline positive anti-CRP test predicted poor response to therapy. Our data also confirm previous findings of associations between anti-CRP and disease activity. This indicates that anti-CRP could be helpful to assess disease activity and response to therapy in SLE nephritis, and highlights the hypothesis of a pathogenetic role for anti-CRP antibodies in lupus nephritis.Original Publication:Christopher Sjöwall, Agneta Zickert, Thomas Skogh, Jonas Wetterö and Iva Gunnarsson, Serum levels of autoantibodies against C-reactive protein correlate with renal disease activity and response to therapy in lupus nephritis, 2009, Arthritis Research & Therapy, (11), 6, R188.http://dx.doi.org/10.1186/ar2880Licensee: Biomed Central / BioMed Centralhttp://www.biomedcentral.com

Renal expression and serum levels of high mobility group box 1 protein in lupus nephritis

INTRODUCTION: High mobility group box 1 protein (HMGB1) is a nuclear DNA binding protein acting as a pro-inflammatory mediator following extracellular release. HMGB1 has been increasingly recognized as a pathogenic mediator in several inflammatory diseases. Elevated serum levels of HMGB1 have been detected in autoimmune diseases including Systemic lupus erythematosus (SLE). However, the local expression of HMGB1 in active lupus nephritis (LN) is not known. Here we aimed to study both tissue expression and serum levels of HMGB1 in LN patients with active disease and after induction therapy. METHODS: Thirty-five patients with active LN were included. Renal biopsies were performed at baseline and after standard induction therapy; corticosteroids combined with immunosuppressive drugs. The biopsies were evaluated according to the World Health Organization (WHO) classification and renal disease activity was estimated using the British Isles lupus assessment group (BILAG) index. Serum levels of HMGB1 were analysed by western blot. HMGB1 expression in renal tissue was assessed by immunohistochemistry at baseline and follow-up biopsies in 25 patients. RESULTS: Baseline biopsies showed WHO class III, IV or V and all patients had high renal disease activity (BILAG A/B). Follow-up biopsies showed WHO I to II (n = 14), III (n = 6), IV (n = 3) or V (n = 12), and 15/35 patients were regarded as renal responders (BILAG C/D). At baseline HMGB1 was significantly elevated in serum compared to healthy controls (P < 0.0001). In all patients, serum levels decreased only slightly; however, in patients with baseline WHO class IV a significant decrease was observed (P = 0.03). Immunostaining revealed a pronounced extranuclear HMGB1 expression predominantly outlining the glomerular endothelium and in the mesangium. There was no clear difference in HMGB1 expression comparing baseline and follow-up biopsies or any apparent association to histopathological classification or clinical outcome. CONCLUSIONS: Renal tissue expression and serum levels of HMGB1 were increased in LN. The lack of decrease of HMGB1 in serum and tissue after immunosuppressive therapy in the current study may reflect persistent inflammatory activity. This study clearly indicates a role for HMGB1 in LN

Mutations in genes encoding complement inhibitors CD46 and CFH affect the age at nephritis onset in patients with systemic lupus erythematosus

INTRODUCTION: Inherited deficiencies of several complement components strongly predispose to systemic lupus erythematosus (SLE) while deficiencies of complement inhibitors are found in kidney diseases such as atypical hemolytic uremic syndrome (aHUS). METHODS: The exons of complement inhibitor genes: CD46 and CFH (factor H) were fully sequenced using Sanger method in SLE patients with nephritis originating from two cohorts from southern and mid Sweden (n = 196). All identified mutations and polymorphisms were then analyzed in SLE patients without nephritis (n = 326) and healthy controls (n = 523). RESULTS: We found non-synonymous, heterozygous mutations in CFH in 6.1% patients with nephritis in comparison to 4.0% and 5.4% in patients without nephritis and controls, respectively. No associations of SLE or nephritis with common variants in CFH (V62I/Y402H/E936D) were found. Furthermore, we found two non-synonymous heterozygous mutations in CD46 in SLE patients but not in controls. The A353V polymorphism, known to affect function of CD46, was found in 6.6% of nephritis patients vs 4.9% and 6.1% of the non-nephritis SLE patients and controls. The presence of mutations in CD46 and CFH did not predispose to SLE or nephritis but was associated with earlier onset of nephritis. Furthermore, we found weak indications that there is one protective and one risk haplotype predisposing to nephritis composed of several polymorphisms in non-coding regions of CD46, which were previously implicated in aHUS. CONCLUSION: SLE nephritis is not associated with frequent mutations in CFH and CD46 as found in aHUS but these may be modifying factors causing earlier onset of nephritis

Low-density granulocytes are related to shorter pregnancy duration but not to interferon alpha protein blood levels in systemic lupus erythematosus

BACKGROUND: An increased risk of pregnancy complications is seen in women with systemic lupus erythematosus (SLE), but the specific immunopathological drivers are still unclear. Hallmarks of SLE are granulocyte activation, type I interferon (IFN) overproduction, and autoantibodies. Here we examined whether low-density granulocytes (LDG) and granulocyte activation increase during pregnancy, and related the results to IFNα protein levels, autoantibody profile, and gestational age at birth. METHODS: Repeated blood samples were collected during pregnancy in trimesters one, two, and three from 69 women with SLE and 27 healthy pregnant women (HC). Nineteen of the SLE women were also sampled late postpartum. LDG proportions and granulocyte activation (CD62L shedding) were measured by flow cytometry. Plasma IFNα protein concentrations were quantified by single molecule array (Simoa) immune assay. Clinical data were obtained from medical records. RESULTS: Women with SLE had higher LDG proportions and increased IFNα protein levels compared to HC throughout pregnancy, but neither LDG fractions nor IFNα levels differed during pregnancy compared to postpartum in SLE. Granulocyte activation status was higher in SLE relative to HC pregnancies, and it was increased during pregnancy compared to after pregnancy in SLE. Higher LDG proportions in SLE were associated with antiphospholipid positivity but not to IFNα protein levels. Finally, higher LDG proportions in trimester three correlated independently with lower gestational age at birth in SLE. CONCLUSION: Our results suggest that SLE pregnancy results in increased peripheral granulocyte priming, and that higher LDG proportions late in pregnancy are related to shorter pregnancy duration but not to IFNα blood levels in SLE

Open Access

Serum levels of autoantibodies against C-reactive protein correlate with renal disease activity and response to therapy in lupus nephriti

IL-17 and IL-23 in lupus nephritis - association to histopathology and response to treatment

Background: Recent studies indicate a central role for the IL-23/IL-17 axis in the pathogenesis of lupus nephritis (LN) but the importance in the context of treatment outcome is unknown. We studied various cytokines, including the IL-23/IL-17 axis, in association to histopathology and response to therapy. Methods: Fifty-two patients with active LN were included. Renal biopsies were performed at baseline and after immunosuppressive treatment. Serum levels of TNF-alpha, IFN-gamma, IL-6, IL-10, IL-17, IL-23 and TGF-beta were analysed at both biopsy occasions and in 13 healthy controls. IL-17 expression in renal tissue was assessed by immunohistochemistry. Biopsies were evaluated regarding WHO-classification and renal disease activity was estimated using the BILAG-index. Improvement of 2 grades in renal BILAG was regarded complete response, and 1 grade partial response. Results: At baseline, all patients had high disease activity (BILAG A/B). Baseline levels of IL-6, IL-10, IL-17, IL-23 (p &lt; 0.001) and IFN-gamma (p = 0.03) were increased in patients vs. controls. In contrast, TGF-beta was lower in patients compared to controls (p &lt; 0.001). Baseline levels of IL-17 were higher in patients with persisting active nephritis (WHO III, IV, V) after treatment, i.e. a poor histological response, vs. WHO I-II (p &lt; 0.03). At follow-up, IL-23 were higher in BILAG-non-responders vs. responders (p &lt; 0.05). Immunostaining of renal tissue revealed IL-17 expression in inflammatory infiltrates. Conclusions: High baseline IL-17 predicted an unfavourable histopathological response, and BILAG-non-responders had high IL-23, indicating that that a subset of LN-patients has a Th-17 phenotype that may influence response to treatment and could be evaluated as a biomarker for poor therapeutic response

IL-17 and IL-23 in lupus nephritis - association to histopathology and response to treatment

Background: Recent studies indicate a central role for the IL-23/IL-17 axis in the pathogenesis of lupus nephritis (LN) but the importance in the context of treatment outcome is unknown. We studied various cytokines, including the IL-23/IL-17 axis, in association to histopathology and response to therapy. Methods: Fifty-two patients with active LN were included. Renal biopsies were performed at baseline and after immunosuppressive treatment. Serum levels of TNF-alpha, IFN-gamma, IL-6, IL-10, IL-17, IL-23 and TGF-beta were analysed at both biopsy occasions and in 13 healthy controls. IL-17 expression in renal tissue was assessed by immunohistochemistry. Biopsies were evaluated regarding WHO-classification and renal disease activity was estimated using the BILAG-index. Improvement of 2 grades in renal BILAG was regarded complete response, and 1 grade partial response. Results: At baseline, all patients had high disease activity (BILAG A/B). Baseline levels of IL-6, IL-10, IL-17, IL-23 (p &lt; 0.001) and IFN-gamma (p = 0.03) were increased in patients vs. controls. In contrast, TGF-beta was lower in patients compared to controls (p &lt; 0.001). Baseline levels of IL-17 were higher in patients with persisting active nephritis (WHO III, IV, V) after treatment, i.e. a poor histological response, vs. WHO I-II (p &lt; 0.03). At follow-up, IL-23 were higher in BILAG-non-responders vs. responders (p &lt; 0.05). Immunostaining of renal tissue revealed IL-17 expression in inflammatory infiltrates. Conclusions: High baseline IL-17 predicted an unfavourable histopathological response, and BILAG-non-responders had high IL-23, indicating that that a subset of LN-patients has a Th-17 phenotype that may influence response to treatment and could be evaluated as a biomarker for poor therapeutic response

IFN-λ1 with Th17 axis cytokines and IFN-α define different subsets in systemic lupus erythematosus (SLE).

BACKGROUND: Interferon (IFN)-α is thought to have a pivotal role in systemic lupus erythematosus (SLE), and type III IFNs (IFN-λ) were recently also associated with SLE. In this study, we measured levels of IFN-α, IFN-λ1, and related cytokines, such as IL-17A, IL-23, and interferon-γ-induced protein 10 (IP-10), in a Karolinska University Hospital cohort of patients with SLE and control subjects. The objective of the study was to investigate if cytokine measurements could identify different subsets of patients with active SLE and higher disease damage. METHODS: We included 261 patients with SLE and 261 population control subjects. All participants underwent a standardized clinical examination. Medical files were reviewed. Patients with SLE were assessed for current organ manifestations, disease activity, and damage. Routine blood parameters, complement levels, and serology were analyzed at the time of inclusion. Levels of IFN-λ1, IFN-α, IL-17A, IL-23, and IP-10 were measured by enzyme-linked immunosorbent assay. RESULTS: IFN-λ1 and IFN-α were detected in 29% and 44% of patients, respectively, but their levels did not correlate. High serum levels of IFN-λ1 were positively associated with antinucleosome antibodies and lymphopenia but negatively with musculoskeletal damage. Positive correlations between levels of IFN-λ1, IL-17A, and IL-23 were observed. Patients with high levels of these three cytokines had more disease damage, especially renal impairment. High levels of IFN-α were associated with mucocutaneous disease; leukopenia; and low complement, Ro/SSA, and La/SSB. Vascular events and antiphospholipid antibodies were uncommon. We identified two subgroups with high disease activity: one with double-high IFN-λ1 and IFN-α and another with IP-10(high). The former had more neuropsychiatric manifestations, and the latter had more arthritis. Increased levels of both types I and III IFNs were found in a proportion of population control subjects. Therefore, high IFN levels do not seem to be SLE-specific biomarkers. CONCLUSIONS: Measurements of circulating IFN-λ1 and IFN-α define subsets of patients with SLE with different characteristics. Levels of IFN-λ1 correlate with T-helper type 17 cytokines and identify a subgroup with more damage. High disease activity is associated with either simultaneous upregulation of IFN-λ1 and IFN-α or independently with IP-10. Our findings could be of major importance when tailoring therapy for patients with SLE with agents targeting IFN pathways