High rate of progression to symptomatic multiple myeloma in patients with smoldering myeloma and isolated osteoporotic vertebral fracture.

Multiple myeloma (MM) frequently causes vertebral fractures (VF). Some are lytic lesions and others have the aspect of benign osteoporotic fractures not requiring anti-myeloma treatment. We explored outcome of these patients with smoldering myeloma (SM) and osteoporotic VF. In this retrospective bi-centric study, patients were identified using a systematic keyword search on electronic medical records. Patients with SM and isolated VF of osteoporotic aspect without indications for myeloma-specific therapy were included. Overall, 13 (7 %) of the 184 identified patients had SM and VF confirmed to be osteoporotic (median number of VF was 3). During follow-up, 12 (92 %) patients evolved to symptomatic MM, 7 (54 %) of them within 18 months (early progressors). Myeloma defining events were new lytic bone lesions in 7 patients (53.8 %). The serum calcium level was significantly higher in the early progressor group (median 2.35 IQR [2.31-2.38] and 2.28 IQR [2.21-2.29] respectively, p = 0.003). Early progressors had a higher number of VF at diagnosis (3.0 [2.0-5.5] vs 1.0 [1.0-2.5], p = 0.18) and more frequently evolved to symptomatic MM because of lytic bone lesions (5 [71 %] vs 2 [33 %], p = 0.13) compared to late progressors. VF of osteoporotic appearance in the context of SM is a rare situation but at high risk of rapid progression to symptomatic MM, suggesting that they may represent bone fragility linked to MM infiltration rather than solely osteoporotic fractures. Further studies are needed to assess if earlier treatment might be beneficial in this population.

Complete remission after a single bisphosphonate infusion in isolated bone Langerhans cell histiocytosis lesion: a case report and a narrative review of the literature.

Langerhans cell histiocytosis (LCH) is a rare disease with limited treatment options. We present a case involving a 57-year-old woman afflicted with an isolated LCH bone osteolytic lesion. A single bisphosphonate infusion significantly alleviated pain, and follow-up scans via CT, PET-CT, and MRI revealed a substantial recalcification of the lesion. Conducting an extensive literature review, we identified 46 cases documenting the efficacy of bisphosphonates in the context of LCH. These findings have raised interest in bisphosphonate infusion as a simple therapeutic alternative in similar situations, with benefits in terms of bone recalcification and pain control for individuals with LCH.

Identification of distinct subgroups of Sjögren's disease by cluster analysis based on clinical and biological manifestations: data from the cross-sectional Paris-Saclay and the prospective ASSESS cohorts.

BACKGROUND: Sjögren's disease is a heterogenous autoimmune disease with a wide range of symptoms-including dryness, fatigue, and pain-in addition to systemic manifestations and an increased risk of lymphoma. We aimed to identify distinct subgroups of the disease, using cluster analysis based on subjective symptoms and clinical and biological manifestations, and to compare the prognoses of patients in these subgroups. METHODS: This study included patients with Sjögren's disease from two independent cohorts in France: the cross-sectional Paris-Saclay cohort and the prospective Assessment of Systemic Signs and Evolution of Sjögren's Syndrome (ASSESS) cohort. We first used an unsupervised multiple correspondence analysis to identify clusters within the Paris-Saclay cohort using 26 variables comprising patient-reported symptoms and clinical and biological manifestations. Next, we validated these clusters using patients from the ASSESS cohort. Changes in disease activity (measured by the European Alliance of Associations for Rheumatology [EULAR] Sjögren's Syndrome Disease Activity Index [ESSDAI]), patient-acceptable symptom state (measured by the EULAR Sjögren's Syndrome Patient Reported Index [ESSPRI]), and lymphoma incidence during follow-up were compared between clusters. Finally, we compared our clusters with the symptom-based subgroups previously described by Tarn and colleagues. FINDINGS: 534 patients from the Paris-Saclay cohort (502 [94%] women, 32 [6%] men, median age 54 years [IQR 43-64]), recruited between 1999 and 2022, and 395 patients from the ASSESS cohort (370 [94%] women, 25 [6%] men, median age 53 years [43-63]), recruited between 2006 and 2009, were included in this study. In both cohorts, hierarchical cluster analysis revealed three distinct subgroups of patients: those with B-cell active disease and low symptom burden (BALS), those with high systemic disease activity (HSA), and those with low systemic disease activity and high symptom burden (LSAHS). During follow-up in the ASSESS cohort, disease activity and symptom states worsened for patients in the BALS cluster (67 [36%] of 186 patients with ESSPRI score <5 at month 60 vs 92 [49%] of 186 at inclusion; p<0·0001). Lymphomas occurred in patients in the BALS cluster (five [3%] of 186 patients; diagnosed a median of 70 months [IQR 42-104] after inclusion) and the HSA cluster (six [4%] of 158 patients; diagnosed 23 months [13-83] after inclusion). All patients from the Paris-Saclay cohort with a history of lymphoma were in the BALS and HSA clusters. This unsupervised clustering classification based on symptoms and clinical and biological manifestations did not correlate with a previous classification based on symptoms only. INTERPRETATION: On the basis of symptoms and clinical and biological manifestations, we identified three distinct subgroups of patients with Sjögren's disease with different prognoses. Our results suggest that these subgroups represent different heterogeneous pathophysiological disease mechanisms, stages of disease, or both. These findings could be of interest when stratifying patients in future therapeutic trials. FUNDING: Fondation pour la Recherche Médicale, French Ministry of Health, French Society of Rheumatology, Innovative Medicines Initiative 2 Joint Undertaking, Medical Research Council UK, and Foundation for Research in Rheumatology.

Asterics: a simple tool for the ExploRation and Integration of omiCS data.

BACKGROUND: The rapid development of omics acquisition techniques has induced the production of a large volume of heterogeneous and multi-level omics datasets, which require specific and sometimes complex analyses to obtain relevant biological information. Here, we present ASTERICS (version 2.5), a publicly available web interface for the analyses of omics datasets. RESULTS: ASTERICS is designed to make both standard and complex exploratory and integration analysis workflows easily available to biologists and to provide high quality interactive plots. Special care has been taken to provide a comprehensive documentation of the implemented analyses and to guide users toward sound analysis choices regarding some specific omics data. Data and analyses are organized in a comprehensive graphical workflow within ASTERICS workspace to facilitate the understanding of successive data editions and analyses leading to a given result. CONCLUSION: ASTERICS provides an easy to use platform for omics data exploration and integration. The modular organization of its open source code makes it easy to incorporate new workflows and analyses by external contributors. ASTERICS is available at https://asterics.miat.inrae.fr and can also be deployed using provided docker images.

Efficacy and management of tocilizumab in polymyalgia rheumatica: results of a multicenter retrospective observational study.

OBJECTIVES: The efficacy of anti-IL6 receptors such as Tocilizumab (TCZ) was demonstrated in patients with Polymyalgia Rheumatica (PMR) in two recent randomized controlled trials. The objective of this multicentre retrospective study was to assess the efficacy of TCZ in PMR patients requiring GC-sparing treatment, as well as different strategies for TCZ withdrawal. METHODS: We conducted a multicentre study in French tertiary health care departments for patients with PMR. PMR patients receiving off-label TCZ between 2015 and 2022 were included. The primary end point was the proportion of patients tapering to glucocorticoids (GCs) ≤5mg/day 6 months after the first TCZ infusion. The secondary endpoints were the proportion in whom GC was discontinued during follow-up, and the proportion of patients in whom TCZ was discontinued. RESULTS: Fifty-three PMR patients were included. Thirty-one (31) patients suffered from active PMR despite csDMARDs. GCs were ≤5mg/day in 77% of the patients (95% confidence interval [CI95%]: 36-89) at 6 months, and in 97% of the patients at 12 months. Six and 12 months after the first TCZ infusion, the proportions of GC-free patients were 22.5% (CI95%: 12.7-37.8) and 58.3% (CI95%: 43.2-74.1), respectively. Among TCZ withdrawal strategies, TCZ infusion spacing and TCZ dose reduction were more successful (success in 87% and 79% of attempts, respectively) than TCZ discontinuation (success in 52% of attempts; p= 0.012 and p= 0.039, respectively). CONCLUSION: In GC-dependent PMR patients, treatment with TCZ led to a drastic decrease in GC dose and remission of PMR. TCZ dose reduction or TCZ infusion spacing are good options to consider in TCZ withdrawal.

Association between radiographic and functional outcome in vertebral osteomyelitis SPONDIMMO, a 6-month prospective multicenter cohort.

OBJECTIVES: This study aimed to describe radiographic and functional evolution over 6 months in a large cohort of VO patients. METHODS: We prospectively recruited patients with VO from 2016 to 2019 in 11 French centers. X-rays were performed at baseline, 3 months, and 6 months to assess progression using structural and static criteria. Functional impairment was evaluated using the Oswestry Disability Index (ODI) at 3 months and 6 months. RESULTS: Two hundred and twenty-two patients were included. Mean age was 67.8±14 years, mostly men (67.6%). After 3 months, there was a significant increase in vertebral fusion (16.4% vs 52.7%), destruction of vertebral bodies (10.1% vs 22.8%), and of all the static features (frontal angulation (15.2% vs 24.4%), segmental (34.6% vs 56%) and regional (24.5% vs 41%) kyphosis). From 3 to 6 months, among the different X-ray abnormalities, only the complete fusion progressed significantly (16.6% vs 27.2%). Median ODI showed significant improvement from 3 to 6 months (24, IQR [11.5-38] vs 16, IQR [6-34]). At 6 months, 14.1% of the patients had a severe disability, 2% a major disability. The persistence of vertebral destruction at 6 months was associated with a higher ODI (16, IQR [7.5-30.5] vs 27, IQR [11.5-44.5]). No differences in radiological progression were observed with immobilization using a rigid brace. CONCLUSION: Our study demonstrates structural and static radiographic progression after 3 months. Only the complete fusion progressed over the long-term. Functional impairment was associated with persistence of vertebral destruction.

Changes of anti-citrullinated peptide antibodies titers after biologic treatment in patients with rheumatoid arthritis: a systematic literature review and retrospective study.

OBJECTIVES: There is an increasing body of evidence suggesting a direct pathophysiological role of anti-citrullinated peptide antibodies (ACPA) in rheumatoid arthritis (RA), and immunological remission could be a target for treatment. However, data related to the ability of biologics to reduce ACPA titres are contradictory.We aimed to evaluate the changes in ACPA titres after treatment with different biologics in patients with RA. METHODS: As a first step, a systematic review of the literature available on 3 biologics (TNFi, abatacept and rituximab) and ACPA in patients with RA was performed in Pubmed and Cochrane. As a second step, a retrospective study was performed: all RA patients treated with the 3 above-mentioned biologics were identified. To be included in the analysis, patients had to have at least two titres of ACPA (one before and one after biologic treatment) available. ACPA titres were compared before and after treatment in each of the treatment groups. RESULTS: As a result of the literature review, 24 articles were retained confirming that the data on change in ACPA under biologics is contradictory, particularly for abatacept and TNFi. 144 RA patients (79.3% female, mean age: 56 years) were included in the retrospective analysis: 59 patients had received rituximab, 31 abatacept, 55 TNFi. ACPA titres decreased significantly with rituximab but not with abatacept nor TNFi. Modelling of ACPA titres over follow-up confirmed the significant decrease of ACPA over time rituximab. CONCLUSIONS: In this real-life study, ACPA titres only significantly decreased after treatment with rituximab.

Tolerance and efficacy of targeted therapies prescribed for off-label indications in refractory systemic autoimmune diseases: data of the first 100 patients enrolled in the TATA registry (TArgeted Therapy in Autoimmune Diseases).

OBJECTIVES: To assess the tolerance and efficacy of targeted therapies prescribed off-label in refractory low-prevalence autoimmune and inflammatory systemic diseases. METHODS: The TATA registry (TArgeted Therapy in Autoimmune Diseases) is a prospective, observational, national and independent cohort follow-up. The inclusion criteria in the registry are as follows: age >18 years; low-prevalence autoimmune and inflammatory systemic disease treated with off-label drugs started after 1 January 2019. RESULTS: Hundred (100) patients (79 women) were enrolled. The median age was 52.5 years (95% CI 49 to 56) and the median disease duration before enrolment was 5 years (3 to 7). The targeted therapies at enrolment were as follows: Janus kinase/signal transducers and activators of transcription inhibitors (44%), anti-interleukin (IL)-6R (22%), anti-IL-12/23, anti-IL-23 and anti-IL-17 (9%), anti-B cell activating factor of the tumour necrosis factor family (5%), abatacept (5%), other targeted treatments (9%) and combination of targeted treatments (6%). 73% of patients were receiving corticosteroid therapy at enrolment (median dose 10 mg/day). The current median follow-up time is 9 months (8 to 10).Safety: 11 serious infections (incidence rate of 14.8/100 patient-years) and 1 cancer (1.3 cancers/100 patient-years) were observed. Two patients died from severe COVID-19 (2.7 deaths/100 patient-years).Efficacy: the targeted treatment was considered effective by the clinician in 56% of patients and allowed, in responders, a median reduction of oral corticosteroids of 15 (9 to 21) mg/day, below 7.5 mg/day in 76% of patients, while 28% discontinued. CONCLUSION: These initial results of the TATA registry confirm the diversity of targeted treatments prescribed off-label in refractory autoimmune diseases and their corticosteroid-sparing effect when effective. Tolerance was acceptable in these refractory patients with a long history of treatment with immunosuppressive drugs.

Use of a bDMARD or tsDMARD for the management of inflammatory arthritis under checkpoint inhibitors: an observational study.

OBJECTIVE: There is limited experience regarding the use of biological disease-modifying antirheumatic drug (bDMARD) and JAK inhibitor (JAKi) for the management of immune checkpoint inhibitors (ICI)-induced inflammatory arthritis. We aimed to assess their efficacy and safety in this setting. METHODS: Using the Club Rhumatismes and Inflammation French network, we conducted a multicentre, retrospective, observational study of patients with cancer diagnosed with inflammatory arthritis under ICI(s) and treated with bDMARD or JAKi. Clinical data were collected using a standardised case report form. RESULTS: Twenty patients (60% men, median age 69.5 years) were included, with rheumatoid arthritis (RA)-like (n=16), polymyalgia rheumatica-like (n=2) or psoriatic arthritis-like (n=2) clinical presentation. Two patients had pre-existing RA. 90% were treated with glucocorticoids as first-line therapy and 60% received methotrexate prior to bDMARD or JAKi. Anti-interleukin-6 receptor (IL-6R) therapy was used in 13/20 patients (65%), leading to clinical improvement in 11/13 patients (85%), but one patient experienced intestinal perforation and cancer progression was noticed in 6/13 patients (46%). Tumour necrosis factor inhibitors were used in 5/20 patients (25%), with improvement in 4/5 patients (80%) and cancer progression was observed in 3/5 patients (60%). Two infections (diverticulitis and pneumonitis) were reported. Anakinra, baricitinib and ustekinumab were each used in one patient. Median duration of the bDMARD or JAKi was 17 weeks. CONCLUSION: Anti-IL-6R therapy is currently the most common strategy in patients with ICI-induced inflammatory arthritis and insufficient response to glucocorticoids and methotrexate, leading to improvement in >80%. Overall, cancer progression occurred in about half of patients and whether the bDMARD/JAKi impacted the tumour response remains to be determined.

Rituximab Impairs B Cell Response But Not T Cell Response to COVID-19 Vaccine in Autoimmune Diseases.

OBJECTIVE: Antibody response to the messenger RNA (mRNA) COVID-19 vaccine has been shown to be diminished in rituximab (RTX)-treated patients. We undertook this study to compare humoral and T cell responses between healthy controls, patients with autoimmune diseases treated with RTX, and those treated with other immunosuppressants, all of whom had been vaccinated with 2 doses of the mRNA COVID-19 vaccine. METHODS: We performed anti-spike IgG and neutralization assays just before and 28 days after the second BNT162b2 (Pfizer-BioNTech) vaccine dose. The specific T cell response was assessed in activated CD4 and CD8 T cells using intracellular flow cytometry staining of cytokines (interferon-γ, tumor necrosis factor, and interleukin-2) after stimulation with SARS-CoV-2 spike peptide pools. RESULTS: A lower proportion of responders with neutralizing antibodies to the vaccine was observed in the RTX group (29%; n = 24) compared to the other immunosuppressants group (80%; n = 35) (P = 0.0001) and the healthy control group (92%; n = 26) (P < 0.0001). No patients treated with RTX in the last 6 months showed a response. Time since last infusion was the main factor influencing humoral response in RTX-treated patients. The functional CD4 and CD8 cellular responses to SARS-CoV-2 peptides for each single cytokine or polyfunctionality were not different in the RTX group compared to the other immunosuppressants group or the control group. In RTX-treated patients, the T cell response was not different between patients with and those without a humoral response. CONCLUSION: RTX induced a diminished antibody response to the mRNA COVID-19 vaccine, but the functional T cell response was not altered compared to healthy controls and autoimmune disease patients treated with other immunosuppressants. Further work is needed to assess the clinical protection granted by a functionally active T cell response in the absence of an anti-spike antibody response.

Spine immobilization and neurological outcome in vertebral osteomyelitis SPONDIMMO, a prospective multicentric cohort.

OBJECTIVE: The aim of our study was to describe spine immobilization in a multicentric cohort of vertebral osteomyelitis (VO), and evaluate its association with neurological complications during follow-up. METHODS: We prospectively included patients from 2016 to 2019 in 11 centers. Immobilization, imaging, and neurological findings were specifically analyzed during a 6-month follow-up period. RESULTS: 250 patients were included, mostly men (67.2%, n=168). Mean age was 66.7±15 years. Diagnosis delay was 25 days. The lumbo-sacral spine was most frequently involved (56.4%). At diagnosis, 25.6% patients (n=64) had minor neurological signs and 9.2% (n=23) had major ones. Rigid bracing was prescribed for 63.5% (n=162) of patients, for a median of 6 weeks, with variability between centers (P<0.001). The presence of epidural inflammation and abscess on imaging was associated with higher rates of rigid bracing prescription (OR 2.33, P=0.01). Frailness and endocarditis were negatively associated with rigid bracing prescription (OR 0.65, P<0.01, and OR 0.42, P<0.05, respectively). During follow up, new minor or major neurological complications occurred in respectively 9.2% (n=23) and 6.8% (n=17) of patients, with similar distribution between immobilized and non-immobilized patients. CONCLUSION: Spine immobilization prescription during VO remains heterogeneous and seems associated inflammatory lesions on imaging but negatively associated with frailness and presence of endocarditis. Neurological complications can occur despite rigid bracing. Our data suggest that in absence of any factor associated with neurological complication spine bracing might not be systematically indicated. We suggest that spine immobilization should be discussed for each patient after carefully evaluating their clinical signs and imaging findings.

Response to COVID-19 mRNA vaccination in multiple myeloma is conserved but impaired compared to controls.

Patients with multiple myeloma are at high risk of severe forms of COVID-19. Despite data showing diminished response to vaccine, the era of highly efficient mRNA vaccine might be a gamechanger. We sought to examine response to mRNA vaccine between healthy controls (n = 28) and multiple myeloma (MM) patients (n = 27). Response was analyzed 1 month after the second dose of anti-SARS-CoV-2 BNT162b2 vaccine. Multiple myeloma patients showed diminished levels of Anti-Spike IgG levels compared to controls, but with a high proportion of patients achieving a humoral response (89% vs. 97% in controls). Neutralizing antibodies were present in 74% of patients versus 96% of controls. Patients under current daratumumab treatment had neutralizing activity of anti-SARS-CoV-2 antibodies. Multiple myeloma patients show diminished response to SARS-COV-2 vaccine but with still high response rate. The main potential risk factor of non-response to COVID-19 vaccine was uncontrolled disease under treatment.

Denosumab in active Charcot neuro-osteoarthropathy of the foot.

OBJECTIVE: Active Charcot Neuro-osteoarthropathy (CN) is a rare and severe complication of peripheral neuropathy that leads to deformity and disability. No pharmacological treatment is available. Increased osteoclastic activity plays a central role in active CN, particularly via receptor activator of nuclear factor ligand (RANK-L). We aimed to describe clinical, morphological and metabolic imaging effects of denosumab, a fully human monoclonal anti- RANK-L antibody, in active CN. METHODS: In this open-label study, we included all consecutive patients with active refractory CN treated with denosumab in our tertiary center. Baseline and follow-up assessment included clinical examination, biological and imaging procedures (morphological and metabolic) before and after treatment. RESULTS: Seven patients were treated with denosumab between 2017 and 2020 and followed for a median of 16 months [6-39]. All patients clinically improved, 4 further relapsed after a median of 4 months [3-33]. Four patients were retreated with the same efficacy. Imaging follow-up available in 5 patients showed stability of structural damage (radiography) and a significant decrease of metabolic activity (FDG PET-CT) in 4 of them. No adverse event or hypocalcemia was observed. CONCLUSION: In patients with refractory active CN, denosumab had a clinical effect, prevented bone and joint destruction, together with a metabolic effect, as assessed by FDG PET-CT. These results justify the conduction of a randomized controlled trial to assess the efficacy of denosumab in acute CN.

Discovery of Anti-SS-A Antibodies during Stroke Investigations in Young Adults: What Impact?

OBJECTIVES: French national guidelines recommend searching for anti-SS-A antibodies during the second-line assessment of stroke in adults < 55 years of age in the absence of an identified etiology. We aimed to assess the impact of finding anti-SS-A antibodies during the etiological investigations of stroke in young adults. METHODS: Medical files from all patients ≤ 55 years of age admitted to a single stroke unit during a five-year period and for whom anti-SS-A antibodies were positive were retrospectively analyzed. RESULTS: Twelve patients were included (9 women; median age 48.5 years), with a rate of anti-SS-A antibody positivity of 1.6% (95% confidence interval [0.71-2.55] %; 12/735 admissions). The etiologies of the 12 ischemic events based on the TOAST classification were large-artery atherosclerosis (n = 1), cardioembolism (n = 1), small-vessel disease (n = 1), other determined etiology (n = 3), multiple etiology (n = 1), and no determined etiology (n = 5). A connective tissue disease (CTD) was discovered in 8/12 patients (1 primary Sjögren's Syndrome, 1 mixed CTD, 1 systemic sclerosis, 2 antiphospholipid syndromes, 1 undetermined CTD, 2 lupus). Anti-SSA antibodies were not directly responsible for the stroke in any of the 12 cases. A link between the autoimmune disease and the neurological vascular episode could be hypothesized for four patients, but it never influenced the therapeutic decision. CONCLUSIONS: Finding anti-SS-A antibodies during the etiological assessment of a stroke of young adults is rare. However, it may be worthwhile to refer the patient to a rheumatologist/an internist because CTD may be discovered and may require specific follow-up.

Small fiber neuropathy in Sjögren syndrome: Comparison with other small fiber neuropathies.

INTRODUCTION: We compared histological and clinical profiles of primary Sjögren syndrome (pSS) small fiber neuropathy (SFN; pSS-SFN) with idiopathic SFN (i-SFN) and hereditary transthyretin amyloidosis SFN (hATTR-SFN) and described the evolution of pSS-SFN. METHODS: All patients with pSS-SFN, i-SFN, and hATTR-SFN confirmed by reduced intraepidermal nerve fiber density on skin biopsy were retrospectively included, and their characteristics were compared. To analyze prognosis of pSS-SFN, patients prospectively underwent a second evaluation. RESULTS: Fifteen pSS-SFN, 17 hATTR-SFN, and 11 i-SFN were included. Time to diagnosis SFN was longer in pSS-SFN and i-SFN than in hATTR-SFN. Painful and non-length-dependent patterns were more frequent in pSS-SFN than in hATTR-SFN. Twelve (80%) patients with pSS-SFN had a non-length-dependent pattern. Ten patients with pSS were reassessed after 3.1 years (1.7-4.7); none developed large fiber neuropathy linked to pSS. DISCUSSION: Primary Sjögren syndrome SFN is characterized by a more frequent non-length-dependent pattern compared with i-SFN and hATTR-SFN. Primary Sjögren syndrome SFN did not evolve through large fiber neuropathy.

Immunization to rituximab is more frequent in systemic autoimmune diseases than in rheumatoid arthritis: ofatumumab as alternative therapy.

OBJECTIVES: The frequency and consequences of anti-drug antibodies to rituximab (RTX-ADA) are not well known in RA and even less in other systemic auto-immune diseases (sAID). We aimed to evaluate the frequency, consequences and predictive factors of RTX-ADA in RA and sAID. METHODS: All patients presenting with RA or other sAID treated with RTX from 2012 to 2017 in our tertiary reference centre for sAID were retrospectively studied. Patients who were tested for RTX-ADA were identified. RESULTS: One hundred and ninety-nine patients were treated with RTX (RA: 124, other sAID: 75). Among 62/199 (31.1%) tested for RTX-ADA, 14 were positive: 3/35 RA (8.6%) and 11/27 (40.7%) other sAID, (P = 0.0047). Among the whole RTX-treated populations, the frequency of RTX-ADA was 2.4% and 14.7% (P = 0.0026) in RA and sAID, respectively. Most of the immunized patients had infusion reactions to second or subsequent RTX cycles (11/14) and loss of efficacy (2/14). Predictive factors of immunization were sAID vs RA (78.6% vs 21.4%, P = 0.026, adjusted odds ratio (OR) = 5.35[1.43-54.75]) and African ethnicity (57.1% vs 4.2%, P < 0.001, adjusted OR = 9.25 [5.08-302.12]). Associated immunosuppressive therapy did not protect against immunization. Three patients with pSS immunized against RTX were treated with ofatumumab with complete remission of their disease. CONCLUSION: Immunization against RTX is more frequent in other sAID than in RA. Testing for RTX-ADA must be performed in patients with infusion reactions or loss of efficacy especially if they are of African origin. Immunized patients might be treated efficiently and safely with ofatumumab. This alternative should be further evaluated for sAID.