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Paraneoplastic neurological syndromes (PNS) are caused by nervous system-targeting aberrant anti-tumoral immune responses. We review the updated criteria for PNS diagnosis, incorporating novel information on clinical phenotypes, neuronal autoantibodies (Nabs), and tumors. The impact of the oncologic use of immune checkpoint inhibitors (ICI) on PNS occurrence is also addressed.Clinical phenotypes and Nabs are redefined as "high/intermediate/low" risk, following the frequency of cancer association. Nabs, the diagnostic hallmark of PNS, can target intracellular or surface neuronal proteins, with important prognostic and pathogenic implications. Many novel assays have been incorporated into laboratory diagnostics, that is becoming increasingly complex. ICI fight tumors, but favor autoimmunity, thus increasing the incidence of PNS-like disorders. Overcoming the old PNS criteria, the new ones are centered around the presence of tumor. Clinical presentation, Nabs, and tumor findings are translated in diagnostic scores, providing a useful tool for PNS diagnosis and management.

BackgroundGranulocyte invasion into the brain is a pathoanatomical feature differentiating neuromyelitis optica spectrum disorder (NMOSD) from multiple sclerosis (MS). We aimed to determine whether granulocyte activation markers (GAM) in cerebrospinal fluid (CSF) can be used as a biomarker to distinguish NMOSD from MS, and whether levels associate with neurological impairment.MethodsWe quantified CSF levels of five GAM (neutrophil elastase, myeloperoxidase, neutrophil gelatinase-associated lipocalin, matrixmetalloproteinase-8, tissue inhibitor of metalloproteinase-1), as well as a set of inflammatory and tissue-destruction markers, known to be upregulated in NMOSD and MS (neurofilament light chain, glial fibrillary acidic protein, S100B, matrix metalloproteinase-9, intercellular adhesion molecule-1, vascular cellular adhesion molecule-1), in two cohorts of patients with mixed NMOSD and relapsing-remitting multiple sclerosis (RRMS).ResultsIn acute NMOSD, GAM and adhesion molecules, but not the other markers, were higher than in RRMS and correlated with actual clinical disability scores. Peak GAM levels occurred at the onset of NMOSD attacks, while they were stably low in MS, allowing to differentiate the two diseases for ≤21 days from onset of clinical exacerbation. Composites of GAM provided area under the curve values of 0.90–0.98 (specificity of 0.76–1.0, sensitivity of 0.87–1.0) to differentiate NMOSD from MS, including all anti-aquaporin-4 protein (aAQP4)-antibody-negative patients who were untreated.ConclusionsGAM composites represent a novel biomarker to reliably differentiate NMOSD from MS, including in aAQP4−NMOSD. The association of GAM with the degree of concurrent neurological impairment provides evidence for their pathogenic role, in turn suggesting them as potential drug targets in acute NMOSD.

Naphthalenediimide dye was used to fabricate polymeric 3D printed colorimetric sensors for bases, to detect aqueous, vapor and organic phases.

Background and ObjectivesWe sought to identify early factors associated with relapse and outcome in paediatric-onset myelin oligodendrocyte glycoprotein antibody-associated disorders (MOGAD).MethodsIn a multicenter retrospective cohort of pediatric MOGAD (≤18 years), onset features and treatment were compared in patients with monophasic vs relapsing disease (including cases with follow-up ≥12 months after onset or relapse at any time) and in patients with final Expanded Disability Status Scale (EDSS) 0 vs ≥1 at last follow-up (including cases with follow-up >3 months after last event or EDSS0 at any time). Multivariable logistic regression models were used to evaluate factors associated with relapsing disease course and EDSS ≥ 1 at final follow-up.ResultsSeventy-five children were included (median onset age 7 years; median 30 months of follow-up). Presentation with acute disseminated encephalomyelitis was more frequent in children aged 8 years or younger (66.7%, 28/42) than in older patients (30.3%, 10/33) (p= 0.002), whereas presentation with optic neuritis was more common in children older than 8 years (57.6%, 19/33) than in younger patients (21.4%, 9/42) (p= 0.001). 40.0% (26/65) of patients relapsed. Time to first relapse was longer in children aged 8 years or younger than in older patients (median 18 vs 4 months) (p= 0.013). Factors at first event independently associated with lower risk of relapsing disease course were immunotherapy p= 0.009), corticosteroid treatment for ≥5 weeks (6.7-fold reduced odds of relapse, OR 0.15, 95% CI 0.03–0.80,p= 0.026), and abnormal optic nerves on onset MRI (12.5-fold reduced odds of relapse, OR 0.08, 95% CI 0.01–0.50,p= 0.007). 21.1% (15/71) had EDSS ≥ 1 at final follow-up. Patients with a relapsing course had a higher proportion of final EDSS ≥ 1 (37.5%, 9/24) than children with monophasic disease (12.8%, 5/39) (p= 0.022, univariate analysis). Each 1-point increment in worst EDSS at onset was independently associated with 6.7-fold increased odds of final EDSS ≥ 1 (OR 6.65, 95% CI 1.33–33.26,p= 0.021).DiscussionAt first attack of pediatric MOGAD, early immunotherapy, longer duration of corticosteroid treatment, and abnormal optic nerves on MRI seem associated with lower risk of relapse, whereas higher disease severity is associated with greater risk of final disability (EDSS ≥ 1).

Neurofilament light chains (NfL) are neuron-specific cytoskeletal proteins whose plasmatic concentrations have been explored as a clinically useful marker in several types of dementia. Plasma concentrations of NfL are extremely low, and just two assays are commercially available for their study: one based on the SiMoA™ technology and one based on Ella™. We thus studied plasma levels of NfL with both platforms to check the correlation between them and to assess their potential in the diagnosis of dementia. Plasma NfL levels were measured on 50 subjects: 18 healthy controls, 20 Alzheimer’s disease, and 12 frontotemporal dementia patients. Ella™ returned plasmatic NfL levels significantly higher than SiMoA™, however the results were strongly correlated (r = 0.94), and a proportional coefficient of 0.58 between the two assays was calculated. Both assays detected higher plasma NfL levels in patients with dementia than in the control group (p 0.95). No difference was found between Alzheimer’s and Frontotemporal dementia either using SiMoA™ or Ella™. In conclusion, both the analytical platform resulted effective in analysing plasma levels of NfL. However, the correct interpretation of results requires the precise knowledge of the assay used.

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BackgroundIgG antibodies against myelin oligodendrocyte glycoprotein (MOG-IgG) define a subset of associated disorders (myelin oligodendrocyte glycoprotein associated disorders (MOGAD)) that can have a relapsing course. However, information on relapse predictors is scarce. The utility of retesting MOG-IgG over time and measuring their titres is uncertain. We aimed to evaluate the clinical relevance of longitudinal MOG-IgG titre measurement to predict relapses in patients with MOGAD.MethodsIn this retrospective multicentre Italian cohort study, we recruited patients with MOGAD and available longitudinal samples (at least one >3 months after disease onset) and tested them with a live cell-based assay with endpoint titration (1:160 cut-off). Samples were classified as ‘attack’ (within 30 days since a disease attack (n=59, 17%)) and ‘remission’ (≥31 days after attack (n=295, 83%)).ResultsWe included 102 patients with MOGAD (57% adult and 43% paediatric) with a total of 354 samples (83% from remission and 17% from attack). Median titres were higher during attacks (1:1280 vs 1:640, p=0.001). Median onset titres did not correlate with attack-related disability, age or relapses. Remission titres were higher in relapsing patients (p=0.02). When considering the first remission sample available for each patient, titres >1:2560 were predictors of relapsing course in survival (log rank, pConclusionsPersistent MOG-IgG positivity and high remission titres are associated with an increased relapse risk. Longitudinal MOG-IgG titres could be useful to stratify patients to be treated with long term immunosuppression.

Single reports of Guillain-Barré syndrome (GBS) have been reported worldwide during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. While case reports are likely to be biased toward uncommon clinical presentations, systematic assessment of prospective series can highlight the true clinical features and spectrum. In this prospective, observational study, we included all consecutive patients who developed GBS. In patients with SARS-CoV-2 infection as antecedent, the time-gap between the infection and GBS onset had to be ≤30 days. The referral was a neurological University Research Hospital, in the Italian Region more severely involved by the pandemic, and hospitalizing both COVID+ and non-COVID neurological diseases. Clinical, laboratory, cerebrospinal fluid, and electromyographic features of GBS diagnosed between March 2020 and March 2021 were compared to a retrospective series of GBS diagnosed between February 2019 and February 2020 (control population). Nasopharyngeal swab was still positive at GBS onset in 50% of patients. Mild-to-moderate COVID-related pneumonia, as assessed by X-ray (6 patients) or X-ray plus computerized tomography (2 patients) co-occurred in 6 of 10 patients. GBS diagnosed during the pandemic period, including 10 COVID-GBS and 10 non-COVID-GBS, had higher disability on admission (P = .032) compared to the GBS diagnosed between February 2019 and 2020, possibly related to later hospital referral in the pandemic context. Compared to non-COVID-GBS (n = 10) prospectively diagnosed in the same period (March 2020-2021), post-COVID-GBS (n = 10) had a higher disability score on admission (P = .028), lower sum Medical Research Council score (P = .022) and lymphopenia (P = .025), while there were no differences in GBS subtype/variant, severity of peripheral involvement, prognosis and response to treatment. Cerebrospinal fluid search for SARS-CoV-2 RNA and antiganglioside antibodies were negative in all COVID+ patients. Temporal clustering of cases, coinciding with the waves of the pandemic, and concomitant reduction of the incidence of COVID-negative GBSs may indicate a role for SARS-CoV-2 infection in the development of GBS, although the association may simply be related to a bystander effect of systemic inflammation; lack of prevalence of specific GBS subtypes in post-COVID-GBS also support this view. GBS features and prognosis are not substantially different compared to non-COVID-GBS.

Background Movement disorders can be associated with anti-neuronal antibodies. Methods We conducted a systematic review of cases with documented anti-neuronal antibodies in serum and/or cerebrospinal fluid published in PubMed before April 1, 2020. Only patients with at least one movement disorder were included. We used random forests for variable selection and recursive partitioning and regression trees for the creation of a data-driven decision algorithm, integrated with expert’s clinical feedback. Results Three hundred and seventy-seven studies met eligibility criteria, totaling 844 patients and 13 antibodies: amphiphysin, GAD, GlyR, mGluR1, ANNA-2/Ri, Yo/PCA-1, Caspr2, NMDAR, LGI-1, CRMP5/CV2, ANNA-1/Hu, IgLON5, and DPPX. Stiffness/rigidity/spasm spectrum symptoms were more frequently associated with amphiphysin, GAD, and GlyR; ataxia with mGluR1, ANNA-2/Ri, Yo/PCA-1, Caspr2, and ANNA-1/Hu; dyskinesia with NMDAR and paroxysmal movement with LGI1; chorea/choreoathetosis with CRMP5/CV2, IgLON5, and NMDAR; myoclonus with GlyR and DPPX; tremors with ANNA2/Ri and anti-DPPX; and parkinsonism with IgLON5 and NMDAR. Data-driven classification analysis determined the following diagnostic predictions (with probability selection): psychiatric symptoms and dyskinesia predicted NMDAR (71% and 87%, respectively); stiffness/rigidity/spasm and ataxia, GAD (67% and 47%, respectively); ataxia and opsoclonus, ANNA-2/Ri (68%); chorea/choreoathetosis, CRMP5/CV2 (41%). These symptoms remained the top predictors in random forests analysis. The integration with an expert opinion analysis refined the precision of the approach. Breast and lung tumors were the most common tumors. On neuroimaging, cerebellar involvement was associated with GAD and Yo/PCA-1; temporal involvement with Caspr2, LGI-1, ANNA-1/Hu. Conclusion Selected movement disorders are associated with specific anti-neuronal antibodies. The combination of data-driven and expert opinion approach to the diagnosis may assist early management efforts. Supplementary Information The online version contains supplementary material available at 10.1007/s00415-021-10934-7.

Background and ObjectivesLive cell-based assay (CBA) can detect acetylcholine receptors (AChRs) or muscle-specific tyrosine kinase (MuSK) antibodies (Abs) in a proportion of patients with radioimmunoassay (RIA)-double seronegative myasthenia gravis (dSN-MG). A commercial fixed CBA for AChR and MuSK Abs has recently become available; however, comparative studies on fixed and live CBAs are lacking. In this study, we compared the performance of fixed and live CBAs in patients with RIA-dSN MG and assessed their sensitivity in RIA-positive MG samples and their specificity.MethodsAChR and MuSK Abs were tested in 292 serum samples from 2 Italian MG referral centers by live and fixed CBAs: 192 from patients with MG and 100 from controls. All samples had been previously assessed by RIA: 66 were AChR positive, 40 MuSK positive, and 86 dSN. All controls were negative. Two independent raters assessed the CBA results. Fixed and live CBAs were compared with the McNemar test; interrater and interlaboratory agreement were assessed with Cohen's kappa or interclass correlation coefficient (ICC), as appropriate.ResultsIn 86 RIA-dSN samples, fixed CBA detected Abs in 10 cases (11.6%, 95% CI 5.7–20.3), whereas live CBA detected Abs in 16 (18.6%, 95% CI 11.0–28.5) (p= 0.0143). Of these sera, those positive by fixed CBA were also positive by live CBA. In addition, live CBA could detect MuSK Abs in 4 and AChR Abs in 2 samples that were negative by fixed CBA, providing an 8% (95% CI 2.9–16.6) further increase in the Ab detection rate. These results were confirmed by flow cytometry. In the RIA-positive cohort, the sensitivity for AChR Abs was 98.5% (95% CI 91.9%–99.9%) for fixed CBA and 100% (95% CI 94.6–100) for live CBA (p= 0.1573). For both assays, the sensitivity for MuSK Abs was 100% (95% CI 91.2–100), and the specificity was 100% (95% CI 96.4–100). Interrater agreement was almost perfect for live and fixed CBAs (Cohen's kappa 0.972 and 0.978, respectively), alike interlaboratory agreement. Interrater agreement for the CBA score ranged from good to excellent (ICC: 0.832–0.973).DiscussionFixed CBA represents a valuable alternative to RIA for AChR and MuSK Ab detection in patients with MG and could be considered as a first-step diagnostic test. Live CBA can be useful in the serologic evaluation of RIA- and fixed CBA-negative samples.

Introduction: Myasthenia gravis (MG) is a prototypical autoimmune disease, characterized by pathogenic autoantibodies targeting structures of the neuromuscular junction. Radioimmunoprecipitation assays (RIPAs) represent the gold standard for their detection. However, new methods are emerging to complement, or overcome RIPAs, also with the perspective of eliminating the use of radioactive reagents.Areas covered: We discuss advances in laboratory methods, prompted especially by cell-based assays (CBAs), for the detection of the autoantibodies of MG diagnostics, above all those to the nicotinic acetylcholine receptor (AChR), muscle-specific kinase (MuSK), and low molecular-weight receptor-related low-density lipoprotein-4 (LRP4).Expert opinion: CBA technology makes AChRs aggregate on cell membranes, thus allowing to detect autoantibodies to clustered AChRs, with reduction of seronegative MG cases. The diagnostic relevance of RIPA/CBA-measurable LRP4 antibodies is still unclear, in Caucasian patients at least. Live CBAs for the detection of AChR, MuSK, and LRP4 antibodies might represent an alternative to RIPAs, but first require full validation. CBAs could be used as screening tests, limiting RIPAs for antibody quantification. To this end, ELISAs might be an alternative.Fixation procedures preserving enough degree of antigen conformationality could yield AChR and MuSK CBAs suitable for a wide use in clinical-chemistry laboratories.

Background: Matrix metalloproteinases (MMPs) are a heterogeneous family of endopeptidases that play a role in many physiological functions, including the immune response. An imbalance between the activity of MMPs and their physiological tissue inhibitors (TIMPs) has been proposed in the pathophysiology of different autoimmune disorders. We aimed to assess the plasmatic levels of MMP-2, MMP-9, and their inhibitors TIMP-1 and -2 in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). Subjects and methods: Twenty patients with CIDP and 20 age- and sex-matched healthy controls were enrolled. Plasma concentrations of MMP-2, MMP-9, TIMP-1, and TIMP-2 were determined by the enzyme-linked immunosorbent assay. Results: CIDP subjects had higher MMP-9 concentrations along with TIMP-1 downregulation when compared to controls, with the consequent increase in the MMP-9/TIMP-1 ratio (p

The diagnostic criteria for N-methyl-d-aspartate receptor antibody (NMDAR-Ab) encephalitis require the presence of CSF antibodies against the NMDAR, whereas serum antibodies are considered specific only if accompanied by CSF antibodies. Current assays include in-house immunochemistry (IHC), or cell-based assays (CBA) which use live (L-CBA) or fixed cells (F-CBA), and commercially available fixed-cells CBA (C-CBA), but these have not been compared in parallel. We compared the L-CBA with F-CBA, C-CBA, and IHC using sera and CSFs archived from > 30,000 received for testing and previously positive by L-CBA. Referring neurologists, if identified, provided “definite” or “unlikely” diagnoses of NMDAR-Ab encephalitis for 31 paired serum-CSF samples and 53 unpaired sera. There was good concordance between paired sera and CSFs, with 13/16 “definite” pairs positive, and 7/8 “unlikely” pairs negative in all in-house assays. In unpaired “definite” sera, L-CBA was most sensitive. However, 19/24 serum samples from “unlikely” patients were positive by L-CBA, with only 5/24 and 1/24 positive by F-CBA and IHC, respectively. In available samples, C-CBA demonstrated high sensitivity for CSF, but surprisingly low sensitivity for serum. Overall, regardless of the technique, CSF results were accurate and easy to interpret, but if CSF is unavailable, negative serum C-CBA results in cases with suspected NMDAR-Ab encephalitis could be repeated by a more sensitive in-house assay. Although these assays are sensitive, particularly for CSF, referral of sera with low pre-test probability should be avoided to reduce clinically-irrelevant “false positive” results.

Three-dimensional printing (3DP) is considered among the key-technologies for the next industrial revolution, with considerable effects on production processes, economy, and society. In this contex...

In this work, optically active devices are fabricated by Digital Light Processing (DLP) 3D printing technology employing copper-iodide photoluminescent clusters as smart dyes in the photocurable formulation. These compounds are easy to synthesize, low cost and possess large stoke shift, thermochromic and rigidochromic properties, which make them particularly appealing for the development of optical devices. By dispersing such compounds in photocurable formulations, the same properties are transferred to polymeric materials, enabling the production of a large range of devices. Absorbing in the UV range and emitting in the visible range, those clusters show twofold advantages: on the one hand, competing with the photoinitiator for the light absorption, they allow a better control of the photopolymerization process, enabling the fabrication of precise structures; on the other hand, these possess aesthetic properties, being transparent and then emitting light when irradiated. At last, functional structures, such as 3D printed polymeric waveguides (PWGs) and downshifting devices, are fabricated and investigated but even other uses can be envisaged, such as cryogenic optical thermometers.

Background: Neurological immune-related adverse events (nirAEs) are rare toxicities of immune-checkpoint inhibitors (ICI). With the increase of ICI oncological indications, their incidence is growing. Their recognition and management remain nevertheless challenging. Methods: A national, web-based database was built to collect cases of neurological symptoms in patients receiving ICI and not attributable to other causes after an adequate workup. Results: We identified 27 patients who developed nirAEs (20 males, median age 69years). Patients received anti-PD1/PDL1 (78%), anti-CTLA4 (4%), or both (19%). Most common cancers were melanoma (30%) and non-small cell lung cancer (26%). Peripheral nervous system was mostly affected (78%). Median time to onset was 43.5days and was shorter for peripheral versus central nervous system toxicities (36 versus 144.5days, p = 0.045). Common manifestations were myositis (33%), inflammatory polyradiculoneuropathies (33%), and myasthenia gravis (19%), alone or in combination, but the spectrum of diagnoses was broad. Most patients received first-line glucocorticoids (85%) or IVIg (15%). Seven patients (26%) needed second-line treatments. At last follow-up, four (15%) patients were deceased (encephalitis, 1; myositis/myasthenia with concomitant myocarditis, 2; acute polyradiculoneuropathy, 1), while seven (26%) had a complete remission, eight (30%) partial improvement, and six (22%) stable/progressing symptoms. ICI treatment was discontinued in most patients (78%). Conclusions: Neurological irAEs are rare but potentially fatal. They primarily affect neuromuscular structures but encompass a broad range of presentations. A prompt recognition is mandatory to timely withheld immunotherapy and administrate glucocorticoids. In corticoresistant or severely affected patients, second-line treatments with IVIg or plasmapheresis may result in additional benefit.

Autoimmune diseases (AID) are increasingly prevalent conditions which comprise more than 100 distinct clinical entities that are responsible for a great disease burden worldwide. The early recognition of these diseases is key for preventing their complications and for tailoring proper management. In most cases, autoantibodies, regardless of their potential pathogenetic role, can be detected in the serum of patients with AID, helping clinicians in making a definitive diagnosis and allowing screening strategies for early -and sometimes pre-clinical- diagnosis. Despite their undoubted crucial role, in a minority of cases, patients with AID may not show any autoantibody, a condition that is referred to as seronegative AID. Suboptimal accuracy of the available laboratory tests, antibody absorption, immunosuppressive therapy, immunodeficiencies, antigen exhaustion, and immunosenescence are the main possible determinants of seronegative AID. Indeed, in seronegative AID, the diagnosis is more challenging and must rely on clinical features and on other available tests, often including histopathological evaluation and radiological diagnostic tests. In this review, we critically dissect, in a narrative fashion, the possible causes of seronegativity, as well as the diagnostic and management implications, in several AID including autoimmune gastritis, celiac disease, autoimmune liver disease, rheumatoid arthritis, autoimmune encephalitis, myasthenia gravis, Sjögren's syndrome, antiphospholipid syndrome, and autoimmune thyroid diseases.

A 44-year-old previously healthy woman developed acute myelitis in close temporal relationship with ChAdOx1 nCoV-19 vaccine first-dose administration. The neurological involvement was mainly sensory with neuroimaging showing two mono-metameric lesions involving the posterior and lateral cord at dorsal level. Significant improvement was promptly recorded with high-dose intravenous steroids, with complete recovery within one month. The strict temporal relationship between vaccination and myelitis, together with the absence of clues pointing to alternative diagnoses, might suggest a conceivable role for anti-SARS-CoV-2 vaccine as immunological trigger, although a causal relationship has yet to be established and our preliminary observation suggests caution., Graphical abstract Unlabelled Image

Introduction/Aims Coronavirus disease 2019 (COVID‐19), a disease caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection, has become a global pandemic. Patients with myasthenia gravis (MG), often treated with immunosuppressants, might be at higher risk of developing COVID‐19 and of demonstrating a severe disease course. We aimed to study prevalence and describe features of COVID‐19 in MG patients. Methods In May 2020, we conducted telephonic interviews with MG patients followed at our referral center. We collected structured data regarding MG and COVID‐19, which was diagnosed as probable or confirmed according to the European Centre for Disease Prevention and Control case definition. We compared confirmed‐COVID‐19 prevalence calculated from the beginning of the pandemic in MG patients with that of the overall Pavia district. Results We interviewed 162 MG patients (median age, 66 y; interquartile range 41‐77; males 59.9%), 88 from the Pavia district. Three patients had SARS‐CoV‐2‐confirmed by polymerase chain reaction and eight had probable‐COVID‐19. In the Pavia district, the prevalence of confirmed‐COVID‐19 among MG patients (1/88, 1.14%) and overall population (4777/546 515, 0.87%) did not differ (P = .538). Higher Myasthenia Gravis Foundation of America clinicalclass and the need for recent rescue treatment, but not ongoing immunosuppressive treatments, were associated with COVID‐19 risk. Of 11 MG patients with probable/confirmed‐COVID‐19, 3 required ventilator support, and 2 elderly patients died of COVID‐19 respiratory insufficiency. Only 1 of11 patients experienced worsening MG symptoms, which improved after increasing their steroid dose. Discussion The risk of COVID‐19 in MG patients seems to be no higher than that of the general population, regardless of immunosuppressive therapies. In our cohort, COVID‐19 barely affected MG course.

Natalizumab (NZM), a humanized monoclonal IgG4 antibody to α4 integrins, is used to treat patients with relapsing-remitting multiple sclerosis (MS)1,2, but in about 6% of the cases persistent neutralizing anti-drug antibodies (ADAs) are induced leading to therapy discontinuation3,4. To understand the basis of the ADA response and the mechanism of ADA-mediated neutralization, we performed an in-depth analysis of the B and T cell responses in two patients. By characterizing a large panel of NZM-specific monoclonal antibodies, we found that, in both patients, the response was polyclonal and targeted different epitopes of the NZM idiotype. The neutralizing activity was acquired through somatic mutations and correlated with a slow dissociation rate, a finding that was supported by structural data. Interestingly, in both patients, the analysis of the CD4+ T cell response, combined with mass spectrometry-based peptidomics, revealed a single immunodominant T cell epitope spanning the FR2-CDR2 region of the NZM light chain. Moreover, a CDR2-modified version of NZM was not recognized by T cells, while retaining binding to α4 integrins. Collectively, our integrated analysis identifies the basis of T-B collaboration that leads to ADA-mediated therapeutic resistance and delineates an approach to design novel deimmunized antibodies for autoimmune disease and cancer treatment. An analysis of T cell specificities sufficient to sustain a neutralizing anti-drug antibody response offers a potential approach for enhancing the clinical efficacy of a therapeutic humanized antibody.

Multiple sclerosis (MS) is an acquired demyelinating disease of the central nervous system (CNS) that traditionally has been considered to be mediated primarily by T cells. Increasing evidence, however, suggests the fundamental role of B cells in the pathogenesis and development of the disease. Recently, anti-CD20 B cell-based therapies have demonstrated impressive and somewhat surprising results in MS, showing profound anti-inflammatory effects with a favorable risk-benefit ratio. Moreover, for the first time in the MS therapeutic scenario, the anti-CD20 monoclonal antibody ocrelizumab has been granted for the treatment of the primary progressive form of the disease. In this review, we provide a brief overview about anti-CD20 B cell-based therapies in MS, in the perspective of their influence on the future management of the disease, and of their possible positioning in a new wider therapeutic scenario.