Search

Objectives To investigate key factors that may contribute to the variability of rituximab-mediated peripheral and renal B cell depletion (BCD) in SLE. Methods We analysed: (i) CD19+ B cell counts in patients with SLE before and 1, 2, 3 and 6 months after treatment with rituximab, comparing them with RA patients; (ii) the presence of B cells in renal biopsies after rituximab therapy; (iii) whether the duration of BCD correlated with patient demographics and B cell expression of CD20 and FcγRIIb; and (iv) the effect of B cell activation factor (BAFF) on the efficiency of rituximab and obinutuzumab at inducing BCD in whole blood assays, in vitro. Results In SLE (n = 71), the duration of BCD was shorter compared with RA (n = 27). B cells were detectable in renal biopsy samples (n = 6) after treatment with rituximab in all patients with poor response while peripheral blood B cells remained low or undetectable in the same patients. There were no significant relationships between peripheral BCD and patient age, disease duration, serum C3 levels or the level of expression of B cell surface proteins CD20 and FcγRIIb. Obinutuzumab was more efficient than rituximab at inducing BCD in whole blood assays, regardless of excess BAFF. Conclusions BCD in SLE is less efficient than in RA. Renal B cell presence following rituximab treatment was associated with poor outcomes. No significant relationships between any measured B cell related, clinical or laboratory parameters and the efficiency of BCD by rituximab was found. Obinutuzumab was superior to rituximab at inducing BCD.

It is now two decades since Rituximab was first used in the treatment of patients with systemic lupus erythematosus. There have been many challenges but in spite of failing to meet its primary endpoints in two clinical trials it is widely used for many aspects of lupus, its side-effects and the possibility that combining it with Benlysta may be of value. We also consider the proposal that it may provide a useful initial therapy. In this review, we consider the place of Rituximab in the treatment of lupus and anticipate how developments in fully-humanized anti-CD20 monoclonals may well extend the “therapeutic life” of B-cell depletion as a viable treatment option.

Systemic Lupus Erythematosus (SLE) is an autoimmune inflammatory condition with a wide spectrum of disease manifestations and severities, resulting in significant morbidity and mortality. The aetiopathogenesis of SLE is complex. Young women and certain ethnicities are commonly affected, suggesting a significant hormonal and genetic influence. Diverse immunological abnormalities have been described. A characteristic abnormality is the presence of autoantibodies, implicating a central role for B cells in disease pathogenesis and/or perpetuation. Whilst conventional therapies have improved outcomes, a great unmet need remains. Recently, biological therapies are being explored. B-cell depletion therapy with rituximab has been in use off-label for nearly two decades. Inconsistent results between uncontrolled and controlled studies have raised doubts about its efficacy. In this review, we will focus on B cell abnormalities and the rationale behind B-cell depletion therapy with anti-CD20 monoclonal antibody (mAb), rituximab, will be explored including an evaluation of clinical and trial experience. Finally, we will discuss the mechanistic basis for considering alternative anti-CD20 mAbs.

B cells are an essential component of the adaptive immune system. Since the late 1990s biologic drugs targeting B cells have been used to treat not only lymphoproliferative diseases of B-cell lineage cells but also autoimmune diseases, in particular, those associated with autoantibody production. Although some of these agents are relatively safe, they have been associated with serious infections including opportunistic infections. To what extent the infectious complications reported are directly related to the use of the B-cell targeting agent or to previous and/or concomitant immunosuppressive therapies and/or the specific disease being treated is often difficult to ascertain.

Background/Aims Magnetic resonance imaging can facilitate the diagnosis of JIA, but is also increasingly used for monitoring disease activity in individual joints. This prospective study aims to measure the frequency of subclinical synovitis on whole-body MRI, in adolescent patients with JIA. Methods JIA patients were recruited from a tertiary adolescent and young adult rheumatology clinic, between September 2019 and August 2020. All patients were examined by a senior rheumatology registrar, before undergoing a contrast enhanced whole-body MRI scan. Patients were assigned to a clinically active or inactive group, depending on their active joint count (AJC); active patients had AJC≥ 1, while the clinically inactive patients had an AJC =0. The post-contrast, water-only mDixon images were assessed for synovitis by one radiologist, blinded to clinical information. Only joints that were definitely abnormal were counted as synovitic. Eighty-one joints per patient were examined with both methods. The presence of subclinical synovitis in a patient was defined as synovitis in one or more joints on MRI, which were not active clinically. Results Thirty-two patients aged 15 to 24 were included in the analysis. The patient characteristics and the frequency of subclinical synovitis are summarised in the table. Subclinical synovitis was detected in a similar proportion of JIA patients in both active and inactive groups (46.7% vs. 41.2%, P = 0.76). The most frequent region with subclinical synovitis was the hindfoot, detected in 22% (7/32) of JIA patients and 17.2% (11/64) of hindfoot joints assessed by MRI. The second most common joint with clinically unsuspected inflammation was the knee, found in 19% (6/32) of JIA patients and 14% (9/64) knee joints. Similarly, 16% (5/32) of the adolescent patients had active disease in the hip, ankle or midfoot joints. The frequency of elbow involvement was also considerable, with 12% (7/58) of joints with subclinical synovitis in 14% (4/29) of JIA patients. Conclusion In conclusion, 43.8% of JIA patients had subclinical synovitis on whole-body MRI scan with no significant difference between the clinically active vs. inactive JIA patients. Large joints were predominantly affected. Further research is required to validate our findings in a larger cohort of JIA patients. Disclosure V. Choida: None. C. Ciurtin: None. T.J.P. Bray: None. D. Sen: None. C. Fisher: None. M. Leandro: None. M.A. Hall-Craggs: None.

Objectives B cell depletion therapy based on rituximab in patients with RA was pioneered at University College London Hospitals/University College London in 1998. The objective of this study was to evaluate long-term persistence of rituximab and identify factors associated with discontinuation of treatment. Methods Retrospective review of medical records from all rituximab-treated RA patients followed up in a dedicated clinic (1998–2020). Data collected included gender, disease duration, previous DMARDs, autoantibody status, age and concomitant therapy at first cycle, length of follow-up, and number of cycles. Drug survival and factors associated with drug discontinuation were analysed using Kaplan–Meier survival curves, log-rank test and Cox regression analysis. Results A total of 404 patients were included. Median disease duration and age at time of first rituximab cycle were 10 and 57 years, respectively. Median total follow-up was 55 months and median number of cycles five. 93.1% of patients were seropositive. Overall, 31.2% of patients stopped rituximab, with the largest reason for discontinuing being primary inefficacy (42.1%). Comparison of Kaplan–Meier curves showed that rituximab drug survival was lower in seronegative patients and in patients who had previously failed at least one biologic DMARD (bDMARD). Cox regression analysis revealed that rituximab discontinuation was associated with a greater number of previous bDMARDs. Conclusion Many patients with RA achieve good control of their disease with repeated cycles of rituximab treatment. The most common reasons for treatment discontinuation were either primary or secondary inefficacy. Patients who were seronegative and who had previously failed other bDMARDs were more at risk of drug discontinuation.

Background B-cell depletion therapy based on rituximab in patients with seropositive rheumatoid arthritis (RA) was pioneered at UCLH/UCL in 1998. The positive results of the initial open-label UCLH/UCL trials led to the Phase IIa proof of concept trial confirming efficacy and safety for rituximab in the treatment of patients with RA. A Phase III trial followed and licensing in 2006. We report a service evaluation of the UCLH/UCL cohort of RA patients treated with rituximab over the last 20 years. Methods A retrospective review of electronic records from all patients with RA treated with rituximab followed up in a dedicated clinic at UCLH/UCL (1998-2019) were included. Data on gender, age at first treatment, previous DMARDs, concomitant therapy at the time of the first rituximab cycle, total number of rituximab cycles and length of follow-up while on rituximab were collected. For patients currently on rituximab, further information was collected at last follow-up, including concomitant therapy, swollen and tender joint count, global VAS, CRP and ESR. DAS28ESR was calculated. Results 296 patients had received rituximab therapy since November 1998, with 105 remaining on rituximab at final data collection (14/10/2019). Median follow-up was 77.5 months. Clinical data is shown in Table 1. Information for previous DMARDs was only available for 196 patients in the whole cohort, and for 70 patients currently on rituximab. The most common concomitant DMARD at first cycle was methotrexate with a similar percentage receiving methotrexate at last follow-up. The median number of previous DMARDs were 4 and 3 respectively. Within both cohorts approximately 31% of patients received rituximab as their first biologic. Conclusion This retrospective service evaluation of 296 patients with RA who had undergone rituximab therapy since 1998 showed that more than one third remained on rituximab at last follow-up. Of these, 70.2% of patients were in clinical remission or with low disease activity. Most patients (94%) remaining on rituximab were receiving only 1 or no concomitant therapies. Multiple cycles of treatment with rituximab have thus proved to be an effective therapeutic strategy for patients with RA resulting in long-term and highly favourable control of their disease. Disclosures C.M. Norris-Grey None. S. Moore None. G. Cambridge None. V. Reedy None. M. Leandro Consultancies; Genentech: consultancy fees for attending meeting on obinutuzumab trial in lupus nephritis.

Fc gamma receptors (FcγR) are involved in multiple aspects of immune cell regulation, are central to the success of monoclonal antibody (mAb) therapeutics and underpin the pathology of several autoimmune diseases. However, reliable assays capable of accurately measuring FcγR interactions with their physiological ligands, immunoglobulin G (IgG) immune complexes (IC), are limited. A method to study and detect IC interactions with FcγRs was therefore developed. This method, designed to model the signalling pathway of the inhibitory FcγRIIB (CD32B), utilised NanoLuc® Binary Interaction Technology (NanoBiT™) to measure recruitment of the Src homology 2 (SH2) domain-containing inositol phosphatase 1 (SHIP-1) to the immunoreceptor tyrosine-based inhibitory motif (ITIM) of this receptor. Such recruitment required prior crosslinking of an immunoreceptor tyrosine-based activation motif (ITAM)-containing activatory receptor, and evoked luciferase activity in discrete clusters at the cell surface, recapitulating the known biology of CD32B signalling. The assay detected varying forms of experimental IC, including heat-aggregated IgG, Rituximab:anti-idiotype complexes and anti-trinitrophenol (TNP)-TNP complexes in a sensitive manner (≤1µg/ml), and discriminated between complexes of varying size and isotype. Proof-of-concept for the detection of circulating ICs in autoimmune disease was provided, as responses to sera from patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) were detected in small pilot studies. Finally, the method was translated to a stable cell line system. In conclusion, a rapid and robust method for the detection of IC was developed, which has numerous potential applications including the monitoring of IC in autoimmune diseases and the study of underlying FcγR biology.

Summary Serum levels of B cell-activating factor (BAFF) rise following rituximab (RTX) therapy in patients with rheumatoid arthritis (RA). Initiation of naive B cell return to the periphery and autoreactive B cell expansion leading to relapse after RTX may therefore be linked to interactions between BAFF and BAFF-binding receptors (BBR). Relationships between serum BAFF and BBR expression [(BAFFR, calcium signal modulating cyclophilic ligand interactor (TACI) and B cell maturation antigen (BCMA)] were determined on B cell subsets, defined using immunoglobulin (Ig)D/CD38. Twenty pre-RTX and 18 RA patients relapsing after B cell depletion were included. Results were analysed with respect to timing of relapse up to 7 months after peripheral B cell return (≥ 5 B cells/μl) and to serum BAFF levels. After B cell return, B cell populations from relapsing patients had significantly lower BAFFR+ expression compared to HC and pre-RTX patients. The percentage of BAFFR+ B cells increased with time after B cell return and was correlated inversely with serum BAFF levels. BAFFR expression remained reduced. The percentage of TACI+ memory B cells were lower in RA patients after RTX compared with healthy controls (HC). BCMA expression (% and expression) did not differ between patients and HC. Relapse following B cell return appeared largely independent of the percentage of BAFFR+ or percentage of BCMA+ B cells or serum BAFF levels. The lower percentage of TACI+ memory B cells may reduce inhibitory signalling for B cell differentiation. In patients relapsing at longer periods after B cell return, recovery of the B cell pool was more complete, suggesting that selection or expansion of autoreactive B cells may be needed to precipitate relapse.

OBJECTIVE Antibodies to cyclic citrullinated peptides (anti-CCP) in rheumatoid arthritis (RA) can express the inherently autoreactive gene VH4–34, detected using the rat monoclonal antibody 9G4. Patients with the polyarticular subtype of juvenile idiopathic arthritis (JIA) share some but not all of the features of adult patients with RA. This study was undertaken to compare serologic findings for rheumatoid factor (RF), anti-CCP, and 9G4-expressing anti-CCP in a large JIA cohort with a cohort of adult RA patients. METHODS: Serum from 88 patients with polyarticular JIA, 29 patients with enthesitis-related arthritis, 38 patients with extended oligoarthritis, 31 adolescent controls, 35 patients with RA, and 30 adult controls were tested for RF, for IgG, IgA, and IgM anti-CCP, and for 9G4-expressing anti-CCP by enzyme-linked immunosorbent assay. Total serum 9G4-positive IgM was also measured. RESULTS: Of 65 patients with RF-negative polyarticular JIA, 4 (6.2%) were IgG anti-CCP positive. Sera from 20 of 23 patients with RF-positive polyarticular JIA (87.0%), 24 of 35 patients with RA (68.6%), and 1 patient with extended oligoarthritis contained IgG anti-CCP. IgA and IgM anti-CCP levels were lower in the adolescent group (P 80% of patients with RF-positive polyarticular JIA. VH4–34 usage by anti-CCP in both JIA and RA patients suggest elicitation of these autoantibodies through shared pathogenic B cell selection processes.

Background To undertake a retrospective review of patients with SLE who had received Rituximab in order to determine the rates and associated patient characteristics of clinically significant adverse infusion reactions. Methods A descriptive analysis was undertaken of each infusion reaction, which was then assessed using the clinical information available to hypothesise on the possible underlying mechanism(s). Results Records of 136 SLE patients previously treated with 481 individual infusions of Rituximab were reviewed. A total of 22 patients (17.6%) had 28 (5.8% of total infusions) documented clinically significant adverse infusion reactions. Average age at first Rituximab infusion in patients without a reaction was 37 years (range 16–73) compared with 30 years (range 18–56) in those with a reaction. A high proportion of men (18.2%) experienced an infusion reaction. Severity and type of reaction varied. 6.4% of those who had a reaction were not retreated. Conclusions While Rituximab remains an important tool in the treatment of SLE it is important to be aware that rates of infusion reactions may be more significant in SLE than in other diseases. A prospective study is required to better characterise the reactions.

Background Lung disease is described in 5–20% of patients (pts) with Rheumatoid arthritis (RA) and affects parenchyma, pleura, airways and vasculature; drug-induced pulmonary disease also occurs. It is associated with a higher mortality and identification of safe and effective drugs is essential. Objectives Characterize lung involvement in a RA cohort; evaluate rituximab (RTX) effectiveness and safety in RA associated interstitial lung disease (ILD). Methods Retrospective analysis of the electronic records from RA cohort followed at University College Hospital. Lung involvement was based on high resolution computed tomography. Demographic data, smoking status, complementary exams at baseline/follow-up and therapies used were analysed. A sub-analysis of pts treated with rituximab (RTX) evaluated response at 12, 24 and 36 months. Declines of 15% in gas transfer from baseline and/or 10% in forced vital capacity were recognized. Results From 1129 RA pts, 87 (7.7%) had documented lung involvement. Mean age at last follow-up was 68.3±12 years, 74.7% were female and 85.1% Caucasian. Median disease duration was 14 (IQR 8-29) years. 54% of pts had erosive disease. Rheumatoid factor was positive in 88.1% and anti-citrullinated protein antibodies in 87.8%. 23 pts had positive antinuclear antibodies (25 missing data) and 4 anti-Ro, 2 anti-Scl70 and 2 anti-PL12. Secondary Sjogren’s syndrome occurred in 6.9%, cutaneous rheumatoid nodules in 5.7% and cutaneous vasculitis in 1.1%. 11.5% and 43.7% were current and previous smokers, respectively. Mean interval between onset of articular and pulmonary symptoms was 12.3 years; 2 pts had lung disease as a prior manifestation. Types of lung involvement are shown in table 1. At last follow-up appointment 22 pts were still on methotrexate (MTX) and 27 had previously received it. MTX-acute pneumonitis occurred in 2 pts, both in the 1st year of treatment. RTX was used in 26 pts (57.8%) with ILD (14 nonspecific interstitial pneumonia-NSIP, 8 usual interstitial pneumonia-UIP, 2 organising pneumonia-OP). The mean number of cycles was 4 (range 1-12). Two pts were concomitantly receiving mycophenolate mofetil and 1 azathioprine. RTX treatment outcomes are shown in table 2. There were 18 (20.7%) deaths, 7 of them related to ILD (4 UIP, 3 NSIP) and occurred 8.8 years after ILD diagnosis. Two were due to infection, but none was felt to be directly related to immunosuppressive therapy. Conclusion Lung disease occurred in 7.7% of our cohort, with ILD being the commonest presentation (51.7%). MTX was widely used in pts with lung disease with only 2 cases of acute pneumonitis. Although the number of ILD pts treated with RTX was small, the drug improved/stabilized the disease in most NSIP and OP pts. UIP is usually progressive, but our data suggest that disease progression might be put on hold with RTX, at least in a subset of pts. Reference [1] Shaw M, Collins BF, Ho LA, Raghu G. Rheumatoid arthritis-associated lung disease. Eur Respir Rev. 2015 Mar 1;24(135):1–16. Disclosure of Interests None declared

Juvenile systemic lupus erythematosus (JSLE) is characterised by onset before 18 years of age and more severe disease phenotype, increased morbidity and mortality compared to adult-onset SLE. Management strategies in JSLE rely heavily on evidence derived from adult-onset SLE studies; therefore, identifying biomarkers associated with the disease pathogenesis and reflecting particularities of JSLE clinical phenotype holds promise for better patient management and improved outcomes. This narrative review summarises the evidence related to various traditional and novel biomarkers that have shown a promising role in identifying and predicting specific organ involvement in JSLE and appraises the evidence regarding their clinical utility, focusing in particular on renal biomarkers, while also emphasising the research into cardiovascular, haematological, neurological, skin and joint disease-related JSLE biomarkers, as well as genetic biomarkers with potential clinical applications.

B cells are vital for the normal evolution of pregnancy due to their humoral and possible regulatory activities. Our group and others have documented that circulating B-cell subsets undergo changes from normal late pregnancy to the postpartum period. However, the underlying mechanisms are poorly understood. Therefore, this study examined the degree of B-cell activation in normal pregnancy by analyzing the levels of serum markers in healthy pregnant women during the third trimester of pregnancy, the day of delivery, and the postpartum period. METHOD OF STUDY: A prospective study including pregnant and non-pregnant women attending routine care was undertaken at a hospital clinic. Sociodemographic and clinical data were collected, along with peripheral blood samples. The serum levels of soluble CD23 (sCD23), B-cell-activating factor (BAFF), kappa (κ) and lambda (λ) free light chains (FLC), IgA, IgG, and IgM were quantified. RESULTS: Our study included 43 third trimester pregnant and 35 non-pregnant women. In the pregnant women, the median levels of sCD23, BAFF, IgG, and κ FLC were significantly higher during the postpartum period than during the third trimester of pregnancy. Compared to the non-pregnant women, the third trimester pregnant women had higher median BAFF levels and lower sCD23, IgA, IgG, and FLC levels. CONCLUSION: Changes in serum markers of B-cell kinetics that occur during pregnancy often persist into the postpartum period and affect the secretion of immunoglobulins from different classes. Further studies are needed to clarify the biological significance of our observations. info:eu-repo/semantics/publishedVersion

Objective.To investigate the perception and willingness of rheumatology patients to participate in clinical trials. No previous similar studies are available.Methods.We conducted a cross-sectional survey of rheumatology patients using a questionnaire, which comprised 2 demographic questions, two 5-point Likert opinion questions, 19 true/false/unsure knowledge questions, and 1 open question addressing what would help the participant to gain a better understanding about clinical trials.Results.Eighty-five patients returned the questionnaires (response rate 84.1%). The mean number of correct answers to the 19 knowledge questions was 10.5 ± 2.87. Patients with higher versus lower levels of education had significantly higher knowledge scores (mean correct answers 59.4 ± 13.1 vs 39.8 ± 20.4, p = 0.013). They also expressed greater willingness to take part in research (87.5% vs 48.2%, p < 0.001). The patients who agreed to participate in research provided significantly more correct answers (59.4 ± 15.3% vs 47.7 ± 27.2%, p = 0.032). Poor disease control as the main reason to join a clinical trial correlated well with patients’ previous participation in research (r = 0.71; p < 0.05) and the lack of understanding of research principles (defined as less than 50% correct answers to the knowledge questions) correlated with the lack of willingness to participate in clinical trials (r = 0.72; p < 0.05).Conclusion.The results of our study revealed that patients lack information about clinical trials (the correct response rate was only slightly above 50%), and that they had a moderate willingness to take part in clinical trials. The need for educational programs about clinical research was highlighted by the participants to the survey.

Background Serum levels of B cell activating factor (BAFF) rise following Rituximab (RTX) therapy in patients with Rheumatoid arthritis (RA). CD5+IgM+B cells are present within transitional and naive B cell subsets and their increased production or accumulation is associated with some autoimmune diseases. Previous studies have shown that BAFF does not enhance their survival compared with CD5- naive B cells, suggesting that signalling pathways are important in promoting their survival. Objectives To determine serum BAFF levels and BAFF-receptor (BAFF-R) expression in CD5+IgM+B cells in healthy controls (HC), RTX-naive RA patients (pre-RTX), and relapsing at different time points after peripheral B cell repopulation post-RTX treatment, divided into 2 groups: early relapsers (0–3 months post-B cell return) and later relapsers (>4 months post-B cell return). Methods Immunophenotyping of peripheral blood mononuclear cells was used to determine %CD5+IgM+B cells and BAFF-R (% and expression, mean fluorescence intensity (MFI)) in 5 HC, 13 pre-RTX and 12 post-RTX RA patients. Results were analyzed with respect to timing of relapse after peripheral B cell return (≥5 B cells/μL) and serum BAFF levels. Results %CD5+IgM+B cells, but not absolute numbers, were significantly higher in post-RTX early relapsers compared to HC (p 2 =0.88, p 2 =0.47, p 2 =0.76, p 2 =0.51, p 2 =0.4, p Conclusions Early relapsers show increased %CD5+IgM+ naive B cells, and decreased BAFF-R expression, similar to ontogeny and what is seen in cord blood B cells. Whether the increased numbers of CD5+ naive cells were contributing to relapse was not determined but they have the capacity to rapidly mature into autoantibody producing plasma cells, independent of the BAFF/BAFFR system. BAFF-R expression was found to increase with time after B cell return, again mirroring ontogeny with a later relapse showing more normalized BAFF/BAFF-R levels, suggesting their mechanism of relapse may follow a more conventional B cell differentiation pathway. Disclosure of Interest None declared

A better understanding of the variability in clinical response to B-cell-depletion therapy using rituximab in rheumatoid arthritis and systemic lupus erythematosus is important to optimize the use of this therapy and improve patient outcomes. To this end, we review current evidence on factors that affect pharmacokinetics and pharmacodynamics of rituximab, and the biological and clinical response to this drug. Also we briefly describe variability in B-cell depletion and reconstitution following rituximab treatment and summarize elements that have been shown to distinguish responders and nonresponders. Finally, we speculate on the prospects for exploiting the knowledge gained thus far in developing rituximab-based personalized therapy for rheumatoid arthritis and systemic lupus erythematosus.

Objective. A proportion of RA and SLE patients treated with standard doses of rituximab (RTX) display inefficient B cell deletion and poor clinical responses that can be augmented by delivering higher doses, indicating that standard-dose RTX is a sub-optimal therapy in these patients. This study aimed to investigate whether better responses could be achieved with mechanistically different anti-CD20 mAbs. Methods. We compared RTX with obinutuzumab (OBZ), a new-generation, glycoengineered type II anti-CD20 mAb, in a series of in vitro assays measuring B cell cytotoxicity in RA and SLE patient samples. Results. We found that OBZ was at least 2-fold more efficient than RTX at inducing B-cell cytotoxicity in in vitro whole blood assays. Dissecting this difference, we found that RTX elicited more potent complement-dependent cellular cytotoxicity than OBZ. In contrast, OBZ was more effective at evoking Fc gamma receptor-mediated effector mechanisms, including activation of NK cells and neutrophils, probably due to stronger interaction with Fc gamma receptors and the ability of OBZ to remain at the cell surface following CD20 engagement, whereas RTX became internalized. OBZ was also more efficient at inducing direct cell death. This was true for all CD19+ B cells as a whole and in naïve (IgD+CD27−) and switched (IgD−CD27+) memory B cells specifically, a higher frequency of which is associated with poor clinical response after RTX. Conclusion. Taken together, these data provide a mechanistic basis for resistance to rituximab-induced B-cell depletion, and for considering obinutuzumab as an alternative B-cell depleting agent in RA and SLE.

Objective B cell–depletion therapy based on rituximab is a therapeutic option for refractory disease in patients with systemic lupus erythematosus (SLE). The aim of this observational study was to document long‐term effects on B cell function by following serum immunoglobulin levels in patients with SLE treated with rituximab in routine clinical practice. Methods We included 57 consecutive patients with SLE treated with rituximab and concomitant/sequential immunosuppressants and measured serum total IgG, IgM, and IgA and IgG anti‐dsDNA antibodies, over a median of 48 months most recent followup. Flow cytometry was used prospectively to assess B cell phenotypes in 17 of 57 patients. Results Twelve patients (21%) had persistent IgM hypogammaglobulinemia (1,000 IU/ml; normal

SummaryMyalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a heterogeneous condition of unknown aetiology characterized by multiple symptoms including fatigue, post-exertional malaise and cognitive impairment, lasting for at least 6 months. Recently, two clinical trials of B cell depletion therapy with rituximab (anti-CD20) reported convincing improvement in symptoms. A possible but undefined role for B cells has therefore been proposed. Studies of the relative percentages of B cell subsets in patients with ME/CFS have not revealed any reproducible differences from healthy controls (HC). In order to explore whether more subtle alterations in B cell subsets related to B cell differentiation exist in ME/CFS patients we used flow cytometry to immunophenotype CD19+ B cells. The panel utilized immunoglobulin (Ig)D, CD27 and CD38 (classical B cell subsets) together with additional markers. A total of 38 patients fulfilling Canadian, Centre for Disease Control and Fukuda ME/CFS criteria and 32 age- and sex-matched HC were included. We found no difference in percentages of classical subsets between ME/CFS patients and HC. However, we observed an increase in frequency (P < 0·01) and expression (MFI; P = 0·03) of CD24 on total B cells, confined to IgD+ subsets. Within memory subsets, a higher frequency of CD21+CD38– B cells (>20%) was associated with the presence of ME/CFS [odds ratio: 3·47 (1·15–10·46); P = 0·03] compared with HC, and there was a negative correlation with disease duration. In conclusion, we identified possible changes in B cell phenotype in patients with ME/CFS. These may reflect altered B cell function and, if confirmed in other patient cohorts, could provide a platform for studies based on clinical course or responsiveness to rituximab therapy.

Aim: To evaluate the long-term safety of rituximab in our cohort of 173 patients with rheumatoid arthritis treated with rituximab and followed-up for longer than 1 year. Materials & Methods: Retrospective study of adverse events, including infusion reactions, neutropenia, hypogammaglobulinemia, infections, malignancies and development of autoimmune conditions. Results: Safety analysis is based on 768.4 patient-years of observation. Four patients had an episode of early-onset neutropenia; nine patients had late-onset neutropenia, although only two were severe; 27% of the patients in the cohort have experienced respiratory infections; 25% have had low IgM determinations; and 24% have had low IgG determinations. Conclusion: Long-term follow-up of rheumatoid arthritis patients on rituximab therapy has shown efficacy and safety profiles similar to clinical trials. The incidence of hypogammaglobulinemia increased after multiple cycles and could contribute to repeated infections and be a limiting factor for futu...

ObjectivesTo examine the expression of B-cell-activating factor receptor (BAFF-R) on naive CD27− and memory CD27+ B cells in normal individuals and patients with rheumatoid arthritis (RA) undergoing B-cell depletion therapy with rituximab.Patients and MethodsBAFF-R expression on B-cell subsets was determined in normal controls (NC; n=11), active patients with RA pre-rituximab (pre-RX; n=15), relapsing patients either concordant for B-cell repopulation (C-R, n=13) or discordant, with relapse more than 3 months after repopulation (D-R, n=11) and patients in remission over 3 months postrepopulation (discordant non-relapsing (D-NR), n=5). Serum BAFF was measured by ELISA and analysed using Mann–Whitney.ResultsThere was no significant difference between NC, pre-RX and D-NR patients in %BAFF-R-positive B cells or mean fluorescence intensity (MFI) in naive and memory B cells. Relapsing patients had significantly lower MFI and %BAFF-R-positive cells in both naive and memory compartments from NC and pre-RX (C-R and D-R; pConclusionBAFF-R expression was significantly reduced on both naive and memory B cells in patients at relapse, regardless of the relationship with B-cell repopulation or serum BAFF levels. Re-establishment of active disease was also associated with an increase in class-switch recombination. Factors responsible for lower levels of BAFF-R may relate to altered thresholds for autoreactive B-cell generation at relapse in patients with RA.

Objectives: To describe the long-term clinical outcome and safety profile of B cell depletion therapy (BCDT) in patients with systemic lupus erythematosus (SLE). It was also determined whether baseline parameters can predict the likelihood of disease flare. Methods: 32 patients with refractory SLE were treated with BCDT using a combination protocol (rituximab and cyclo-phosphamide). Patients were assessed with the British Isles Lupus Assessment Group (BILAG) activity index, and baseline serology was measured. Flare was defined as a new BILAG ‘A’ or two new subsequent ‘B’s in any organ system. Results: Of the 32 patients, 12 have remained well after one cycle of BCDT (median follow-up 39 months). BCDT was followed by a decrease of median global BILAG scores from 13 to 5 at 6 months (p = 0.006). Baseline anti-extractable nuclear antigen (ENA) was the only identified independent predictor of flare post-BCDT (p = 0.034, odds ratio = 8, 95% CI 1.2 to 55) from multivariable analysis. Patients with low baseline serum C3 had a shorter time to flare post-BCDT (p = 0.008). Four serious adverse events were observed. Conclusion: Autoantibody profiling may help identify patients who will have a more sustained response. Although the long-term safety profile of BCDT is favourable, ongoing vigilance is recommended.

Summary Autoantibodies inhibiting the activity of the metalloproteinase, ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13), underlie the pathogenesis of thrombotic thrombocytopenic purpura (TTP). Rituximab (RTX) combined with plasma-exchange (PEX) is an effective treatment in TTP. Patients can remain in remission for extended periods following PEX/RTX, and this is associated with continuing reduction in antibodies to ADAMTS13. Factors controlling B cell differentiation to autoantibody production, including stimulation through the B cell receptor and interactions with the B cell-activating factor (BAFF), may thus impact length of remission. In this cross-sectional study, we measured naive and memory B cell phenotypes [using CD19/immunoglobulin (Ig)D/CD27] following PEX/RTX treatment in TTP patients at B cell return (n = 6) and in 12 patients in remission 10–68 months post-RTX. We also investigated relationships among serum BAFF, soluble CD23 (sCD23– a surrogate measure of acquiring B memory (CD27+) phenotype) and BAFF receptor (BAFF-R) expression. At B cell return after PEX/RTX, naive B cells predominated and BAFF-R expression was reduced compared to healthy controls (P < 0·001). In the remission group, despite numbers of CD19+ B cells within normal limits in most patients, the percentage and absolute numbers of pre-switch and memory B cells remained low, with sCD23 levels at the lower end of the normal range. BAFF levels were correlated inversely with BAFF-R expression and time after therapy. In conclusion, the long-term effects of RTX therapy in patients with TTP included slow regeneration of memory B cell subsets and persistently reduced BAFF-R expression across all B cell subpopulations. This may reflect the delay in selection and differentiation of potentially autoreactive (ADAMTS13-specific) B cells, resulting in relatively long periods of low disease activity after therapy.

B cell depletion therapy was introduced for auto-antibody associated rheumatic disease in 1998. Encouraging pilot studies in rheumatoid arthritis were followed by randomised controlled trials confirming major benefit. Licensing for use in patients unable to benefit from tumour necrosis factor alpha (TNFalpha) neutralising agents is envisaged shortly. Open studies in other disorders, in particular systemic lupus erythematosus (SLE), have also suggested benefit and its use in life-threatening situations is becoming widespread. Toxicity appears to compare favourably with other agents, but respiratory problems may be more common. Repeated therapy is effective, but may lead to hypogammaglobulinemia. Rituximab is currently the main agent used but other agents are in development. Optimal protocols are not well characterised and will probably be different for different conditions.

B-cell depletion based on rituximab has now been proven to be an effective therapy for seropositive rheumatoid arthritis with a good safety profile. The encouraging results from early, open-label trials have been confirmed in three large, controlled trials. A license for use in patients that have failed antitumor necrosis factor-α agents has been obtained in the USA and is imminent in several other countries. Despite this welcome progress, experience suggests that all patients who respond to B-cell depletion eventually show clinical relapse. Possible mechanisms of relapse include incomplete depletion of pathogenic B cell clones, persistence of long-lived plasma cells producing pathogenic autoantibodies, or persistence of other kinds of cells, such as autoreactive T cells carrying ‘disease memory’. A better understanding of why patients relapse may allow us to optimize B-cell depletion protocols based on rituximab and/or other agents and contribute to the development of B-cell-targeted therapies, with the ...

Objective Autoantibody production in patients with systemic lupus erythematosus (SLE) is associated with abnormalities of B cell function and phenotype. Clinical responses to B cell depletion therapy (BCDT), based on rituximab, are encouraging. Therefore, we undertook this study to investigate the effect of BCDT on antibody profiles. Methods Serial sera from 16 patients with active, refractory SLE were assayed for antinucleosome antibodies, anti–double-stranded DNA (anti-dsDNA), anti–extractable nuclear antigen, anti–tetanus toxoid, and antibodies to pneumococcal capsular polysaccharide for at least 1 year following BCDT. Anti-dsDNA antibodies derived from the VH4.34 immunoglobulin germ line gene (9G4+) were also measured. Results All patients achieved peripheral B cell depletion and improved clinically for at least 3 months. Antinucleosome and anti-dsDNA antibodies decreased to a mean ± SD of 64 ± 37% and 38 ± 33% of baseline values, respectively, by 6–8 months post-BCDT. Levels of other autoantibodies and antimicrobial antibodies were generally unchanged. In the 9 of 16 patients who were still well at 1 year, anti-dsDNA antibodies fell to 42 ± 36% of baseline values at 6–8 months and to 37 ± 33% at 10–14 months. In patients who had disease flares within 1 year of BCDT, levels of these antibodies decreased to 60 ± 40% and 83 ± 93% of baseline values at 6–8 months and at 10–14 months, respectively. Circulating anti-dsDNA antibodies were positive for 9G4 expression in 4 of 6 patients tested, and flares in 2 of these patients were accompanied by rises in 9G4+ anti-dsDNA antibodies. Conclusion These observations suggest that B cell clones committed to producing antinucleosome and anti-dsDNA antibodies, including the VH4.34 subpopulation of anti-dsDNA antibodies, have a relatively rapid turnover compared with B cell clones producing other antibodies. There was also a trend toward a greater and more sustained decrease in anti-dsDNA antibodies in patients with clinical benefit lasting >1 year.

Objectives. To assess the clinical and basic serological consequences of B-cell depletion with rituximab in the treatment of patients with systemic lupus erythematosus (SLE) who have failed conventional immunosuppression. Methods. An open study of 24 patients with severe SLE followed for a minimum of 3 months is reported. In the majority of patients (19 out of 24), 6 months follow-up data are described. Disease activity in these patients was assessed every 1-2 months using the British Isles Lupus Assessment Group (BILAG) system and estimates of anti-double-stranded DNA antibodies and serum C3 levels. During the follow-up period, significant side-effects were sought and the reduction in oral prednisolone was recorded. It was our general practice to stop concomitant immunosuppression (e.g. azathioprine, mycophenolate) when B-cell depletion was given (in most cases in the form of two 1 g intravenous infusions of rituximab 2 weeks apart accompanied by two 750 mg intravenous cyclophosphamide infusions and two methylprednisolone infusions of 250 mg each). Results. Twenty-two patients were female and two male. At the time of B-cell depletion, the mean age was 28.9 yr (range 17-49) and the mean disease duration was 7.9 yr (range 1-18). The global BILAG score (P < 0.00001), serum C3 (P < 0.0005) and double-stranded DNA binding (P < 0.002) all improved from the time of B-cell depletion to 6 months after this treatment. Only one patient failed to achieve B-lymphocyte depletion in the peripheral blood. The period of B-lymphocyte depletion ranged from 3 to 8 months except for one patient who remains depleted at more than 4 yr. Analysis of the regular BILAG assessments showed that improvements occurred in each of the eight organs or systems. The mean daily prednisolone dose fell from 13.8 mg (S.D. 11.3) to 10 mg (S.D. 3.1). Conclusion. In this open study of patients who had failed conventional immunosuppressive therapy, considerable utility in the use of B-cell depletion has been demonstrated. Our data provide strong support for the performance of a full double-blind control trial.

B cell dysfunctionand pathogenicautoantibodyformationare thoughtto be criticalin the pathogenesis of systemic lupus erythematosus (SLE). In this review we will summarize the results of attempts to utilize B cell depletion, based on the use of a chimeric monoclonalantibody(MAb) specific for human CD20, rituximab, for the treatment of patients with SLE.

Objective To explore the changes in serologic variables and clinical disease activity following B lymphocyte depletion in 22 patients with rheumatoid arthritis (RA). Methods B lymphocyte depletion was attained using combination therapy based on the monoclonal anti-CD20 antibody rituximab. Levels of a serologic indicator of inflammation, C-reactive protein (CRP), of antimicrobial antibodies, of autoantibodies including IgA-, IgM-, and IgG-class rheumatoid factors (RF), and of antibodies to cyclic citrullinated peptide (anti-CCP) were assayed. Results The majority of patients showed a marked clinical improvement after treatment with rituximab, with benefit lasting up to 33 months. Levels of total serum immunoglobulins fell, although the mean values each remained within the normal range. Whereas the IgM-RF response paralleled the changes in total serum IgM levels, the levels of IgA-RF, IgG-RF, and IgG and anti-CCP antibodies decreased significantly more than did those of their corresponding total serum immunoglobulin classes. The kinetics for the reduction in CRP levels also paralleled the decreases in autoantibody levels. In contrast, levels of antimicrobial antibodies did not change significantly. B lymphocyte return occurred up to 21 months posttreatment. The time to relapse after B lymphocyte return was often long and unpredictable (range 0–17 months). Relapse was, however, closely correlated with rises in the level of at least one autoantibody. Increased autoantibody levels were rarely observed in the absence of clinical change. Conclusion Following B lymphocyte depletion in patients with RA, a positive clinical response occurred in correlation with a significant drop in the levels of CRP and autoantibodies. Antibacterial antibody levels were relatively well maintained. B lymphocyte return preceded relapse in all patients. There was also a temporal relationship between clinical relapse and rises in autoantibody levels. Although these observations are consistent with a role for B lymphocytes in the pathogenesis of RA, the precise mechanisms involved remain unclear.

B-lymphocyte depletion therapy is being explored in a wide range of autoimmune disorders. In many, there is early evidence for efficacy, and immunosuppression has not been a major problem. The mechanism of action is unclear, but appears to be consistent with the lowering of autoantibody levels, where relevant antibodies are quantifiable. An interesting finding is the persistence of clinical improvement for periods of 1 year or more after B-lymphocyte return, which supports the concept that stochastic generation of rare pathogenic B-lymphocyte subsets may be a rate-limiting step in pathogenesis.

Background The pre-symptomatic stage of Rheumatoid arthritis (RA) is associated with pro-inflammatory cytokines and autoantibodies. High levels and epitope spread by Rheumatoid factors (RhF) and autoantibodies to citrullinated proteins signify progression towards disease expression. In established RA, the persistence of high autoantibody levels reflects production by both long-lived plasma cells and short-lived plasmablasts. Neither the relative contributions to pathogenesis by autoantibodies from either source, nor the factors responsible for deciding the fate of autoantigen specific ‘parent’ B-cells, is understood. Phenotypic markers identifying subsets of autoreactive B-cells are therefore of interest in understanding the origin and perpetuation of the autoimmune response in RA. One such phenotypic marker is the rat monoclonal antibody, 9G4, which recognises an idiotope on immunoglobuins derived from the inherently autoreactive VH-gene, VH4-34. We therefore investigated whether the 9G4 idiotope was expressed on autoantibodies in patients with RA. Methodology/Principal Findings Sera from 19 patients with established RA and those with

Calcium pyrophosphate dihydrate crystal arthropathy (CPPA) is a well known but heterogeneous disease with a variable presentation and course. We present a cross-sectional study undertaken in a Portuguese rheumatology unit with the aim of analysing clinical and radiological patterns of CPPA in our population. The study population included 50 patients, 34 (68%) women and 16 (32%) men. The mean age was 69.8 +/- 8.8 years. The onset features were acute arthritis in 19 (38%) patients and chronic joint complaints in 26 (52%); five (10%) patients were asymptomatic at the time of diagnosis, which was based only on radiological findings. The diagnosis was established in 37 (74%) cases by clinical and radiographic features, in eight (16%) by clinical, X-ray and synovial fluid analysis, and in five (10%) by clinical features and fluid analysis. The disease course was characterised by acute episodic arthritis in 16 (32%) patients and by persistent symptoms (with or without synovitis) in 34 (68%). The pattern of CPPA in 20 (40%) patients was pseudo-osteoarthritis with synovitis, pseudo-osteoarthritis without synovitis in nine (18%), pseudogout in nine (18%), monoarthropathy in eight (16%) and pseudorheumatoid arthritis in four (8%). The phosphocalcium balance was altered in nine (18%) cases: six patients had hypercalciuria two hyperphosphaturia, two hypocalciuria, one hypophosphaturia and one hypercalcemia. Five patients had abnormal thyroid hormone levels, but only one presented with clinical hypothyroidism. Four patients showed increased parathormone levels, but only one presented with clinical hyperparathyroidism. Radiographic findings showed that 43 (86%) patients had meniscus calcifications, 20 (40%) radiocarpal and 16 (32%) calcification of the symphysis pubis. The study confirms the clinical variability of the disease in a population of Portuguese patients. The knee meniscus calcifications were the most sensitive single finding for establishing the diagnosis of CPPA. Almost all our patients had sporadic idiopathic CPPA without associated pathological conditions.

Rheumatoid arthritis (RA) is a chronic inflam matory autoimmune disease that mainly affects diarthrodial joints. It is associated with signifi cant morbidity and, in particular, irreversible joint damage and functional disability, and increased mortality. The diagnosis of RA is mainly clinical, supported by laboratorial and imaging findings. It is relatively easy to make a diagnosis of RA in the typical patient presenting with insidious onset symmetric polyarthritis, involving predominantly the wrists and small joints of the hands and feet with detectable rheumatoid factor (RF) in serum and with x-rays showing periarticular osteopenia with or without decreased joint space or erosions. However, in less characteristic presentations, the diagnosis of early RA can be challenging. This is true, for example, in older patients with a clinical picture of polymyalgia-type symptoms or remitting seronegative symmetrical synovitis with pitting oedema syndrome, in acute presentations with a predominance of systemic symptoms or in patients presenting with a monoarthritis or with an asymmetric oligoarthritis.

In the 1980s and 1990s numerous groups worked on the development of monoclonal antibody (mAb) technology for cell identification and characterization and for therapeutic uses. The initial drive to specifically target B cells was part of the effort to develop more effective and safer therapeutic agents to treat B-cell malignancies. Anti-idiotype antibodies were effective but a different antibody needed to be developed for each patient, contributing to preventing these antibodies from being used in normal clinical practice. Monoclonal antibodies to B-cell lineage-specific antigens were more attractive but choice of antigen was difficult as, for example, shedding or modulation of the antigen could lead to diminished efficacy. Technological advances enabling the production of chimeric human–mouse and humanized or fully human mAb decreased their immunogenicity, increased their half-life, and improved mAb recruitment of host immune effector mechanisms that target cells expressing the specific antigen.

International audience; B-cell depletion therapy (BCDT) based on rituximab (RTX) induces clinical remission in a majority of seropositive patients with Rheumatoid arthritis (RA). However, all patients eventually relapse. The aim of this study was to determine whether dynamic changes in combinations of serological measures of B-cell activation were associated over up to three cycles of BCDT. We included only RA patients who gave an adequate clinical response, as measured by DAS28. Twenty three patients were studied over 1 cycle, 21 over 2, and 15 over 3 cycles of BCDT. Serum analytes including isotypes of Rheumatoid factors (RhF) and anti-citrullinated protein/peptide antibodies (ACPA), B-cell activating factor (BAFF), serum free light chains (SFLC), soluble CD23 (sCD23), antibodies to tetanus toxoid (TT) and to pneumococcal capsular polysaccharide (PCP) were measured by ELISA at 4 key points in each cycle, namely: Baseline (pre-RTX in each cycle); when B-cell depleted (CD19+B-cells < 5/μl); at B-cell return (CD19+B-cells ≥ 5/μl); and at clinical relapse (ΔDAS28 > 1.2). SFLC were used as a measure of plasmablast activity. As sCD23 is cleaved from naïve B-cells coincident with attaining CD27 expression, levels were used as a novel measure of maturation of B-cells to CD27+. The most consistent changes between baseline and B-cell depletion within all 3 cycles were in SFLC, sCD23 and IgM-RhF which fell and in BAFF levels which rose. After 3 complete cycles of BCDT, both IgM autoantibodies and IgG-CCP had decreased, BAFF levels were higher (all p < 0.05); other analytes remained unchanged compared with baseline. Dynamic changes in λSFLC, sCD23, IgM-RhF and BAFF were also consistently associated with relapse in patients with longer clinical responses after B-cell return. Incremental rises in sCD23 levels in cycles 2 and 3 were correlated with time to relapse. Repopulation of the periphery after BCDT is initiated by naïve B-cells and precedes relapse. Our study showed that differentiation into plasmablasts, attended by sCD23 and SFLC production and IgM-RhF specificity may be required to precipitate relapse in patients experiencing longer responses after RTX. These studies also provide novel information related to the resumption of autoimmune responses and their association with B-cell kinetics following BCDT.

Background In patients with Rheumatoid Arthritis (RA) and Systemic Lupus Erythematosus (SLE), who have poor responses to standard doses of rituximab (RTX), enhanced B-cell depletion and improved clinical responses can be achieved with higher doses of RTX. Defects in complement, NK cell function and CD11b polymorphisms associated with SLE may impair the effector mechanisms evoked by RTX whilst high BAFF levels may confer B cells some resistance to apoptosis. Obinutuzumab (OBZ, a Type II anti-CD20 monoclonal antibody [mAb] with afucosylated Fc portion and enhanced affinity for Fcγ receptor III) is more efficient than Rituximab (RTX, a Type I mAb) at inducing malignant B cell cytotoxicity and has recently entered Phase II clinical trials in SLE. Objectives To compare the effects of RTX and OBZ against B cells from patients with RA and SLE in vitro and dissect any differences between the two mAbs in evoking effector mechanisms in RA and SLE. Methods We used flow cytometry to perform: in vitro whole blood B cell depletion assays to compare the efficiency of OBZ and RTX in depleting target B cells; surface fluorescence-quenching assays to determine the extent of mAb internalization; complement dependent cellular cytotoxicity (CDC) assays to assess the ability to recruit complement and lyse target cells; NK cell degranulation assays assessing surface expression of CD107a as a measure of antibody-dependent cellular cytotoxicity (ADCC); and neutrophil activation assays assessing the surface expression of CD62L and CD11B. Annexin V positivity represented cell death in direct cell death (DCD) assay. OBZ-gly (OBZ with Fc glycosylation similar to RTX) was used to assess the effects of afucosylation. All mAb were used at 1μg/mL except for the CDC and DCD assays (10μg/mL). Results OBZ was >2 fold more efficient than RTX at inducing cytotoxicity in B cells from patients with RA (n=31) and SLE (n=34) in whole blood assays. It was also internalized by isolated B cells from SLE patients (n=6) to a significantly lower extent than RTX with a median surface accessible mAb of 75% and 59%, respectively, after 6 hours of incubation. OBZ was at least twice as efficient at inducing NK cell activation, in RA (n=13) and SLE (n=19); and also activated neutrophils more efficiently than RTX in SLE (n=15) (Figure 3). In contrast, RTX was significantly more efficient than OBZ at evoking CDC of isolated B cells (SLE, n=6). OBZ was also more efficient at inducing direct cell death in CD19+ B-cells as a whole and in naive (IgD+CD27-); and switched (IgD-CD27+) memory B-cells, a higher frequency of which is associated with poor clinical response after RTX. Conclusions Obinutuzumab is more efficient than rituximab at inducing B cell cytotoxicity in vitro in both RA and SLE samples. Enhanced direct cell death, reduced CD20 internalization and superior FcR-mediated effector mechanisms are observed, while complement mediated cytotoxicity is reduced. These data provide a mechanistic basis for considering Obinutuzumab as an alternative B cell depleting agent in RA and SLE, in particular. Disclosure of Interest V. Reddy: None declared, C. Klein Employee of: Roche Pharmaceuticals, D. Isenberg Speakers bureau: consultation fees paid directly into a local charity, G. Cambridge: None declared, M. Cragg Grant/research support from: research grant from Roche, M. Leandro Speakers bureau: travel support to attend conferences

Background B cells infiltrate the kidneys of LN pts, and leukocyte-rich tubulointerstitial infiltrates are associated with greater risk for progression to renal failure. High-sensitivity flow cytometry (HSFC) analysis suggests incomplete B-cell depletion in systemic lupus erythematosus (SLE) is associated with nonresponse to rituximab (RTX). Obinutuzumab (Obi) is a glycoengineered type 2 anti-CD20 mAb that binds CD20 differently from RTX, a conventional type 1 anti-CD20 mAb, and depletes B cells to a greater degree than RTX. In preclinical studies, Obi displayed significantly increased antibody-dependent cellular cytotoxicity and enhanced direct cell death over type 1 anti-CD20 mAbs. In the CLL11 trial, which led to FDA breakthrough designation and its licensing in chronic lymphocytic leukemia, Obi demonstrated greater progression-free survival and greater minimal residual disease negativity over RTX even in protected microenvironments such as bone marrow. Double-blind randomized controlled trials demonstrated that type 1 anti-CD20 mAbs added to mycophenolate mofetil (MMF) or cyclophosphamide (CYC) increased the proportions of pts achieving partial renal response (PRR) but had no impact on complete renal response (CRR) rates at 12 months. Although these studies with RTX and ocrelizumab did not meet their respective primary endpoints, EULAR and ACR LN guidelines recommend RTX if treatment with CYC or MMF fails. Objectives The phase 2 study NOBILITY is designed to test the hypothesis that Obi may generate superior CRR rates in pts with active proliferative LN based on its ability to deplete B cells to a greater degree than type 1 anti-CD20 mAbs. The primary objective of this study is to evaluate the effect of Obi compared with placebo (PBO) when added to MMF in pts with class III or IV LN as assessed by the proportion of pts who achieve CRR at wk 52. Key secondary objectives relate to overall response (CRR + PRR), PRR, change in biomarkers of LN disease activity, and time to CRR. Methods Randomized, double-blind, PBO-controlled study to evaluate safety and efficacy of Obi added to MMF and corticosteroids (CS) in pts with ISN/RPS 2003 class III or IV LN. Results The study design is as follows: NOBILITY is a global multicenter study enrolling ∼120 pts with biopsy-proven ISN/RPS 2003 class III or IV LN in the United States, Mexico, Columbia, Argentina, Spain, Israel, Brazil, and France. All pts will be on MMF up to 2.5 g/d and a combination of IV and oral CS to be tapered to 7.5 mg/d by wk 12. All pts will be followed up until wk 104, with the primary endpoint evaluation at wk 52 (figure). NOBILITY also features interim analyses at wk 4 for depletion of peripheral CD19+ B cells by HSFC, centralized evaluation of the renal biopsy, and repeat renal biopsy on the basis of clinical status and local practice. Conclusions NOBILITY, a phase 2 trial evaluating Obi in LN, is grounded on the hypothesis that a type 2 anti-CD20 mAb will induce greater B-cell depletion in the kidneys and associated secondary lymphoid structures, translating to significant CRR rates. Disclosure of Interest T. Schindler Employee of: F. Hoffmann-La Roche, B. Rovin Grant/research support from: Genentech, Consultant for: Genentech, R. Furie: None declared, M. Leandro Grant/research support from: Roche, Consultant for: Roche, Genentech, Chugai, Lilly, BMS, M. Clark Grant/research support from: AbbVie, Consultant for: Genentech, P. Brunetta Shareholder of: Genentech, Employee of: Genentech, J. Garg Shareholder of: Roche, Employee of: Genentech

Background and purpose Seropositivity for Rheumatoid factors and for antibodies to citrullinated (Cit) protein antigens (ACPA) is the strongest predictor for clinical response to Rituximab (rituximab) in rheumatoid arthritis (RA). The aim of this study was to follow fluctuations of IgG- and IgA-ACPA to multiple individual citrullinated protein epitopes in relation to clinical improvement and resumption of symptoms after rituximab. Methods 16 patients with severe, active RA (DAS28 ≥ 5.1) undergoing initial cycles of rituximab were included. All achieved peripheral B-cell depletion ( Results At Baseline, MFI of IgG- and of IgA-Cit antibodies were strongly correlated (R2 = 0.75; p Conclusion Dissection of the ACPA response after rituximab using multiplex bead array revealed diverse kinetics of autoantibody production and followed several distinct patterns, largely un-related to Cit-epitope specificity. At Relapse, rising levels of ACPA with the same specificities as those at baseline suggested re-expansion of residual Cit-specific memory B cells. As B cell return is mandatory for relapse, and with no marked presence of new autoantibody specificities, potential interactions between newly generated and residual B cells could be exploited for more efficient B cell directed therapies.

OBJECTIVE: To investigate whether the incidence of secondary hypogammaglobulinaemia in patients with RA following rituximab was related to patterns of B-cell return and relapse. METHODS: CD19(+) B-cell and serum immunoglobulin (sIg) determinations were done every 2 or 3 months in 137 consecutive patients treated with one or more courses of rituximab-based B-cell depletion therapy. The pattern of B-cell return, either concordant or discordant with relapse, was also recorded. RESULTS: There were 119 responders. Before treatment, three patients had low IgM and four had low IgG. After the first cycle, low IgM or IgG was present in 9.2% (11/119) and 11.8% (14/119) of the patients, respectively, increasing to 38.8% (8/18) and 22.2% (4/18) after five cycles. The mean percent maximum sIg decrease/cycle was relatively constant. The CD19(+) B-cell count at repopulation was not correlated with immunoglobulin (Ig) levels after each cycle. Patients discordant for B-cell return and relapse developed significantly lower serum IgM and more low IgM episodes than concordant patients (P