Publications by authors named "Emanuela Bartoccioni"

29 Publications

  • Page 1 of 1

Long-Lasting Rituximab-Induced Reduction of Specific-But Not Total-IgG4 in MuSK-Positive Myasthenia Gravis.

Front Immunol 2020 5;11:613. Epub 2020 May 5.

Istituto di Neurologia, Università Cattolica del Sacro Cuore, Rome, Italy.

The use of rituximab (RTX), an anti-CD20 monoclonal antibody (Ab), in refractory myasthenia gravis (MG) is associated with a better response in patients with Abs to the muscle-specific tyrosine kinase (MuSK) than in other MG subgroups. Anti-MuSK Abs are mostly IgG4 with proven pathogenicity and positive correlation with clinical severity. The rapid and sustained response to RTX may be related to MuSK Ab production by short-lived Ab-secreting cells derived from specific CD20 B cells. Here, we investigated the long-term effects of RTX in nine refractory MuSK-MG patients with a follow-up ranging from 17 months to 13 years. In patients' sera, we titrated MuSK-specific IgG (MuSK-IgG) and MuSK-IgG4, along with total IgG and IgG4 levels. Optimal response to RTX was defined as the achievement and maintenance of the status of minimal manifestations (MM)-or-better together with ≥ 50% steroid reduction, withdrawal of immunosuppressants, and no need for plasma-exchange or intravenous immunoglobulin. After a course of RTX, eight patients improved, with optimal response in six, while only one patient did not respond. At baseline, MuSK-IgG and MuSK-IgG4 serum titers were positive in all patients, ranging from 2.15 to 49.5 nmol/L and from 0.33 to 46.2 nmol/L, respectively. MuSK Abs mostly consisted of IgG4 (range 63.80-98.86%). RTX administration was followed by a marked reduction of MuSK Abs at 2-7 months and at 12-30 months ( < 0.02 for MuSK-IgG and < 0.01 for MuSK-IgG4). In patients with a longer follow-up, MuSK Ab titers remained suppressed, paralleling clinical response. In the patient who achieved long-term complete remission, MuSK-IgG4 was no longer detectable within 2 years, while MuSK-IgG remained positive at very low titers up to 10 years after RTX. In the patient who did not respond, MuSK-IgG and MuSK-IgG4 remained unchanged. In this patient series, total IgG and IgG4 transiently decreased ( < 0.05) at 2-7 months after RTX. The different trends of reduction between MuSK-IgG4 and total IgG4 after RTX support the view that short-lived Ab-secreting cells are the main producers of MuSK Abs. The ratio between short-lived Ab-secreting cells and long-lived plasma cells may influence the response to RTX, and B-cell severe depletion may reduce self-maintaining autoimmune reactivity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fimmu.2020.00613DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7214629PMC
March 2021

Serological Immunoglobulin-Free Light Chain Profile in Myasthenia Gravis Patients.

J Immunol Res 2018 25;2018:9646209. Epub 2018 Mar 25.

Dipartimento di Medicina di Laboratorio, Fondazione Policlinico Universitario Agostino Gemelli, Università Cattolica del Sacro Cuore, Rome, Italy.

Background: Serological levels of free immunoglobulin light chains (FLCs), produced in excess of heavy chains during synthesis of immunoglobulins by plasma cells, can be considered a direct marker of B cell activity in different systemic inflammatory-autoimmune conditions and may represent a useful predictor of rituximab (RTX) therapeutic efficacy, as reported for rheumatoid arthritis and systemic lupus erythematosus. Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction with antibodies (abs) targeting the acetylcholine receptor (AChR) or the muscle-specific tyrosine kinase (MuSK), inducing muscle weakness and excessive fatigability. As MG course may be remarkably variable, we evaluated the possible use of FLCs as biomarkers of disease activity.

Subjects And Methods: We assessed FLC levels in 34 sera from 17 AChR-MG and from 13 MuSK-MG patients, in comparison with 20 sera from patients with systemic autoimmune rheumatic diseases and 18 from healthy blood donors, along with titers of specific auto-abs and IgG subclass distribution.

Results: We found a statistically significant increase in free chains in both AChR- and MuSK-MG patients, while free chain levels were increased only in AChR-MG. We also observed a significant reduction of both free and chains in 1/4 MuSK-MG patients along with specific abs titer, two months after RTX treatment.

Conclusions: From our data, FLCs appear to be a sensitive marker of B cell activation in MG. Further investigations are necessary to exploit their potential as reliable biomarkers of disease activity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2018/9646209DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5889870PMC
September 2018

Rituximab in myasthenia gravis: a "to be or not to be" inhibitor of T cell function.

Ann N Y Acad Sci 2018 02 25;1413(1):41-48. Epub 2018 Jan 25.

Istituto di Neurologia, Università Cattolica del Sacro Cuore, Rome, Italy.

In recent years, rituximab (RTX), a monoclonal antibody that binds the B lymphocyte membrane protein CD20, has been increasingly used for the treatment of autoimmune diseases, with the rationale of destroying pathogenic B lymphocytes and decreasing autoantibody formation. Surprisingly, RTX has also proven effective in predominantly T cell-mediated diseases, raising the question whether additional mechanisms may play roles in determining the therapeutic response. Here, we review the current literature on the effects of RTX in autoimmune diseases, with special emphasis on myasthenia gravis (MG). To elicit a complete and effective immune response, B and T lymphocytes cooperate in a loop in which they affect each other. Disruption of this cross talk has profound effects on the immune system. RTX is likely to affect the whole spectrum of B cell function, including antigen presentation, cytokine production, and T cell stimulation. In addition, as a small subset of T lymphocytes expresses CD20, its direct targeting by RTX may contribute to the therapeutic effect. Owing to its distinctive immune characteristics, MG proved to be a useful model to investigate the multifaceted implications of B cell depletion.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/nyas.13562DOI Listing
February 2018

Myasthenia gravis with antibodies to MuSK: an update.

Ann N Y Acad Sci 2018 01 21;1412(1):82-89. Epub 2017 Dec 21.

Institute of General Pathology, Catholic University, Fondazione Policlinico Gemelli, Rome, Italy.

Myasthenia gravis with antibodies to the muscle-specific tyrosine kinase (MuSK MG) is a rare disease with distinctive pathogenic mechanisms and clinical features. An acute onset and predominant bulbar muscle weakness are very common and highly suggestive of the disease. On the other hand, a more indolent course, atypical ocular presentation, and signs of cholinergic hyperactivity may complicate the diagnosis. Though MuSK MG is still a severe disease, over the years we have observed a steady reduction in the rate of respiratory crisis and a significant improvement in the clinical outcome, both likely related to earlier diagnosis and timely treatment. Despite the improved management, MuSK MG patients tend to remain dependent on long-term immunosuppressive treatment and may develop permanent disabling weakness. In uncontrolled studies, B cell depletion with rituximab proved effective in most patients with refractory disease, inducing prolonged clinical responses associated with a sustained reduction of serum antibody levels. Promising results from experimental studies and case reports suggest that both 3,4-diaminopyridine and albuterol may be effective as symptomatic agents.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/nyas.13518DOI Listing
January 2018

Diagnostics of myasthenic syndromes: detection of anti-AChR and anti-MuSK antibodies.

Neurol Sci 2017 Oct;38(Suppl 2):253-257

UO Neurologia IV, Istituto Neurologico Carlo Besta, Milan, Italy.

This paper presents the Italian guidelines for autoantibody testing in myasthenia gravis that have been developed following a consensus process built on questionnaire-based surveys, internet contacts and discussions during dedicated workshops of the sponsoring Italian Association of Neuroimmunology (AINI). Essential clinical information on myasthenic syndromes, indications and limits of antibody testing, instructions for result interpretation and an agreed laboratory protocol (Appendix) are reported for the communicative community of neurologists and clinical pathologists.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10072-017-3026-2DOI Listing
October 2017

Pattern of ocular involvement in myasthenia gravis with MuSK antibodies.

J Neurol Neurosurg Psychiatry 2017 09 10;88(9):761-763. Epub 2017 Jun 10.

Institute of General Pathology, Catholic University, Fondazione Policlinico A. Gemelli, Rome, Italy.

Background: Myasthenia gravis (MG) with antibodies to the muscle-specific kinase (MuSK) has a characteristic phenotype. Ocular manifestations have not been systematically evaluated.

Objective: To investigate the features of extrinsic ocular muscle involvement in patients with MuSK-MG.

Methods: We retrospectively evaluated the prevalence, time of onset, clinical pattern and outcome of ocular symptoms in 82 patients with a clinical follow-up ≥2 years.

Results: Ocular manifestations were observed in 79 patients (96.4%) and were the presenting symptoms in 48 (58.5%). Intermittent diplopia with subtle ophthalmoparesis was the most common complaint, ptosis was generally symmetrical and conjugated gaze paresis occurred in 35% of the patients. Ocular manifestations responded well to prednisone and partially to symptomatic treatment. A few patients developed chronic symmetrical ophthalmoparesis, associated with persistent weakness in other muscle groups. All patients with ocular presentation progressed to generalised disease, though weakness spread to other muscle groups was considerably delayed in a few cases.

Conclusions: In MG with antibodies to MuSK, ocular manifestations were as frequent as in other disease subtypes. Symmetrical ophthalmoparesis with conjugated gaze limitation was rather common and associated with low functional disability. A proportion of these patients developed chronic eye muscle paresis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1136/jnnp-2017-315782DOI Listing
September 2017

Low reliability of anti-KIR4.1 peptide auto-antibodies in multiple sclerosis patients.

Mult Scler 2018 06 26;24(7):910-918. Epub 2017 May 26.

Institute of General Pathology, School of Medicine, Università Cattolica del Sacro Cuore, Rome, Italy/Department of Laboratory Medicine, School of Medicine, Fondazione Policlinico Universitario A. Gemelli, Rome, Italy.

Background: Multiple sclerosis (MS) is an autoimmune disease for which auto-antibodies fully validated as diagnostic and prognostic biomarkers are widely desired. Recently, an immunoreactivity against the inward rectifying potassium channel 4.1 (KIR4.1) has been reported in a large proportion of a group of MS patients, with amino acids 83-120 being the major epitope. Moreover, a strong correlation between anti-KIR4.1 and anti-full-length-protein auto-antibodies titer was reported. However, this finding received limited confirmation.

Objective: Validation of the diagnostic potential of anti-KIR4.1 antibodies in 78 MS patients, 64 healthy blood donors, and 42 individuals with other neurological diseases.

Methods: Analysis of anti-KIR4.1 antibodies by enzyme-linked immunosorbent assay (ELISA) using a mouse antiserum we produced as a new ELISA reliability control. Additionally, evaluation of reactivity against 293-T cells transiently transfected with full-length KIR4.1 by flow cytometry.

Results: We found antibodies to KIR4.1 only in 13 out of 78 (16.6%) MS patients; among these, only 2 were positive for anti-full-length KIR4.1 antibodies.

Conclusion: Employing a new reliability control and a new cytofluorometric assay, we cannot support anti-KIR4.1 auto-antibodies as a reliable biomarker in MS.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/1352458517711275DOI Listing
June 2018

Remission of myasthenia gravis with MuSK antibodies during ruxolitinib treatment.

Muscle Nerve 2017 Mar 25;55(3):E12-E13. Epub 2016 Nov 25.

General Pathology, Catholic University, Rome, Italy.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/mus.25458DOI Listing
March 2017

Disease specific enrichment of circulating let-7 family microRNA in MuSK+ myasthenia gravis.

J Neuroimmunol 2016 Mar 7;292:21-6. Epub 2016 Jan 7.

Department of Neuroscience, Clinical Neurophysiology, Uppsala University, Uppsala, Sweden. Electronic address:

Myasthenia gravis (MG) patients with antibodies against the muscle specific tyrosine kinase (MuSK+) have predominantly involvement of cranio-bulbar muscles and do not display thymus pathology, as do acetylcholine receptor antibody seropositive (AChR+) MG patients. In search of novel biomarkers for MuSK+ MG, we evaluated circulating serum microRNAs. Four analyzed microRNAs were specifically elevated in MuSK+ MG patient serum samples: let-7a-5p, let-7f-5p, miR-151a-3p and miR-423-5p. The circulating microRNA profile in MuSK+ MG differs from the profile previously observed in the serum of AChR+ MG, thus indicating the etiological difference between these two entities. We propose that the identified microRNAs could serve as potential serum biomarkers for MuSK+ MG.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jneuroim.2016.01.003DOI Listing
March 2016

Overcoming challenges in the diagnosis and treatment of myasthenia gravis.

Expert Rev Clin Immunol 2016 16;12(2):157-68. Epub 2015 Dec 16.

c Institute of General Pathology , Catholic University , Roma , Italy.

In recent years, the discovery of new autoantigens and the use of sensitive assays have expanded the clinical spectrum of myasthenia gravis (MG). In particular, antibodies binding to clustered acetylcholine receptors and to the low-density lipoprotein receptor-related protein 4 have not only bridged a significant gap in diagnosis but also have relevant clinical implications. MG management includes different therapeutic options, from symptomatic agents as the only therapy in mildly affected cases to combined long-term immunosuppression and thymectomy in patients with severe disabling disease. MG biological diversity can influence the response to therapies and should be taken into account when planning treatment. Biologic agents are promising, though their use is currently limited to patients with refractory disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1586/1744666X.2016.1110487DOI Listing
November 2016

Flow Cytofluorimetric Analysis of Anti-LRP4 (LDL Receptor-Related Protein 4) Autoantibodies in Italian Patients with Myasthenia Gravis.

PLoS One 2015 18;10(8):e0135378. Epub 2015 Aug 18.

Institute of General Pathology, School of Medicine, Università Cattolica S. Cuore, Rome, Italy.

Background: Myasthenia gravis (MG) is an autoimmune disease in which 90% of patients have autoantibodies against the muscle nicotinic acetylcholine receptor (AChR), while autoantibodies to muscle-specific tyrosine kinase (MuSK) have been detected in half (5%) of the remaining 10%. Recently, the low-density lipoprotein receptor-related protein 4 (LRP4), identified as the agrin receptor, has been recognized as a third autoimmune target in a significant portion of the double sero-negative (dSN) myasthenic individuals, with variable frequency depending on different methods and origin countries of the tested population. There is also convincing experimental evidence that anti-LRP4 autoantibodies may cause MG.

Methods: The aim of this study was to test the presence and diagnostic significance of anti-LRP4 autoantibodies in an Italian population of 101 myasthenic patients (55 dSN, 23 AChR positive and 23 MuSK positive), 45 healthy blood donors and 40 patients with other neurological diseases as controls. All sera were analyzed by a cell-based antigen assay employing LRP4-transfected HEK293T cells, along with a flow cytofluorimetric detection system.

Results: We found a 14.5% (8/55) frequency of positivity in the dSN-MG group and a 13% frequency of co-occurrence (3/23) in both AChR and MuSK positive patients; moreover, we report a younger female prevalence with a mild form of disease in LRP4-positive dSN-MG individuals.

Conclusion: Our data confirm LRP4 as a new autoimmune target, supporting the value of including anti-LRP4 antibodies in further studies on Myasthenia gravis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0135378PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4540439PMC
May 2016

A Study of Inflammatory/Necrosis Biomarkers in the Fracture of the Femur Treated with Proximal Femoral Nail Antirotation.

Mediators Inflamm 2015 14;2015:189864. Epub 2015 May 14.

Institute of General Pathology, Catholic University, 00168 Rome, Italy ; Department of Orthopaedic Sciences and Traumatology, University Hospital Agostino Gemelli, Catholic University, 00168 Rome, Italy ; Department of Laboratory Medicine, University Hospital Agostino Gemelli, Catholic University, 00168 Rome, Italy.

Pertrochanteric fractures are common injuries in adults and source of morbidity and mortality among the elderly. Different surgical techniques were recommended for their treatment but undoubtedly they add an additional inflammatory trauma along the fracture itself. Many attempts to quantify the degree of approach-related trauma are carried out through measurements of systemic inflammatory parameters. In this study we prospectively analyzed laboratory data of 20 patients over eighty with pertrochanteric fracture of the femur treated with proximal femoral nail antirotation (PFNA). This is an excellent device for osteosynthesis because it can be easily and quickly inserted by a mini-incision providing stable fixation and early full mobilization. Serum tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP), and plasma creatin kinase (CK) were evaluated 1 hour preoperatively and 24 hours postoperatively. Our results show that PFNA did not induce significant increments in serum levels of inflammatory cytokines TNF-α and IL-6; CRP was elevated preoperatively in correlation with waiting time for surgery; CRP and CK showed a significant increment in the first postoperatory day; CK increment was correlated with surgical time length. We conclude that, for the markers we analyzed, PFNA shows a low biomechanical-inflammatory profile that represents an advantage over other techniques.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2015/189864DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4446479PMC
February 2016

Poly-autoimmunity in patients with myasthenia gravis: A single-center experience.

Autoimmunity 2015 14;48(6):412-7. Epub 2015 Apr 14.

a Institute of Neurology, Catholic University , Rome , Italy .

We evaluated the co-occurrence of autoimmune diseases (ADs) in a large population of myasthenia gravis (MG) patients from a single center. Our survey included 984 patients, 904 with anti-acetylcholine receptor antibodies and 80 with anti-muscle specific kinase antibodies. The anti-acetylcholine receptor positive population included patients with early-onset (age at onset ≤ 50 years), late-onset and thymoma-associated disease. Follow-up ranged 2-40 years. Two-hundred and fourteen ADs were diagnosed in 185 patients; 26 of them had two or more ADs in association with MG. Thyroid disorders were the most common and, together with vitiligo and thrombocytopenia, occurred in all disease subsets. Otherwise, there was a broad variability with partial overlap among patient groups. The highest rate of ADs was observed in early-onset patients, while clusters, i.e. 2 or more ADs other than MG in the same individual, were more common among thymoma cases. Thirty-four diseases were diagnosed at the same time, 88 occurred before and 92 after the onset of MG. On multivariate analysis, immunosuppressive treatment was the only independent variable which negatively influenced the risk of developing other ADs in our cohort.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3109/08916934.2015.1031890DOI Listing
May 2016

Characterization of B cells in muscle-specific kinase antibody myasthenia gravis.

Neurol Neuroimmunol Neuroinflamm 2015 Apr 26;2(2):e77. Epub 2015 Feb 26.

Neuromuscular Division (J.T.G., D.B.S., A.C.G., V.C.J., J.M.M.), Department of Neurology, and Division of Surgical Sciences (J.S.Y., K.J.W.), Department of Surgery, Duke University Medical Center, Durham, NC; Neuromuscular Division (J.F.H.), Department of Neurology, University of North Carolina at Chapel Hill; and Institute of General Pathology (F.S., E.B.) and Department of Neurology (A.E.), Catholic University, Rome, Italy.

Objective: To characterize B-cell subsets in patients with muscle-specific tyrosine kinase (MuSK) myasthenia gravis (MG).

Methods: In accordance with Human Immunology Project Consortium guidelines, we performed polychromatic flow cytometry and ELISA assays in peripheral blood samples from 18 patients with MuSK MG and 9 healthy controls. To complement a B-cell phenotype assay that evaluated maturational subsets, we measured B10 cell percentages, plasma B cell-activating factor (BAFF) levels, and MuSK antibody titers. Immunologic variables were compared with healthy controls and clinical outcome measures.

Results: As expected, patients treated with rituximab had high percentages of transitional B cells and plasmablasts and thus were excluded from subsequent analysis. The remaining patients with MuSK MG and controls had similar percentages of total B cells and naïve, memory, isotype-switched, plasmablast, and transitional B-cell subsets. However, patients with MuSK MG had higher BAFF levels and lower percentages of B10 cells. In addition, we observed an increase in MuSK antibody levels with more severe disease.

Conclusions: We found prominent B-cell pathology in the distinct form of MG with MuSK autoantibodies. Increased BAFF levels have been described in other autoimmune diseases, including acetylcholine receptor antibody-positive MG. This finding suggests a role for BAFF in the survival of B cells in MuSK MG, which has important therapeutic implications. B10 cells, a recently described rare regulatory B-cell subset that potently blocks Th1 and Th17 responses, were reduced, which suggests a potential mechanism for the breakdown in immune tolerance in patients with MuSK MG.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1212/NXI.0000000000000077DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4345633PMC
April 2015

A genome-wide association study of myasthenia gravis.

JAMA Neurol 2015 Apr;72(4):396-404

Department of Neurology, University of Illinois College of Medicine, Chicago.

Importance: Myasthenia gravis is a chronic, autoimmune, neuromuscular disease characterized by fluctuating weakness of voluntary muscle groups. Although genetic factors are known to play a role in this neuroimmunological condition, the genetic etiology underlying myasthenia gravis is not well understood.

Objective: To identify genetic variants that alter susceptibility to myasthenia gravis, we performed a genome-wide association study.

Design, Setting, And Participants: DNA was obtained from 1032 white individuals from North America diagnosed as having acetylcholine receptor antibody-positive myasthenia gravis and 1998 race/ethnicity-matched control individuals from January 2010 to January 2011. These samples were genotyped on Illumina OmniExpress single-nucleotide polymorphism arrays. An independent cohort of 423 Italian cases and 467 Italian control individuals were used for replication.

Main Outcomes And Measures: We calculated P values for association between 8,114,394 genotyped and imputed variants across the genome and risk for developing myasthenia gravis using logistic regression modeling. A threshold P value of 5.0×10(-8) was set for genome-wide significance after Bonferroni correction for multiple testing.

Results: In the overall case-control cohort, we identified association signals at CTLA4 (rs231770; P=3.98×10(-8); odds ratio, 1.37; 95% CI, 1.25-1.49), HLA-DQA1 (rs9271871; P=1.08×10(-8); odds ratio, 2.31; 95% CI, 2.02-2.60), and TNFRSF11A (rs4263037; P=1.60×10(-9); odds ratio, 1.41; 95% CI, 1.29-1.53). These findings replicated for CTLA4 and HLA-DQA1 in an independent cohort of Italian cases and control individuals. Further analysis revealed distinct, but overlapping, disease-associated loci for early- and late-onset forms of myasthenia gravis. In the late-onset cases, we identified 2 association peaks: one was located in TNFRSF11A (rs4263037; P=1.32×10(-12); odds ratio, 1.56; 95% CI, 1.44-1.68) and the other was detected in the major histocompatibility complex on chromosome 6p21 (HLA-DQA1; rs9271871; P=7.02×10(-18); odds ratio, 4.27; 95% CI, 3.92-4.62). Association within the major histocompatibility complex region was also observed in early-onset cases (HLA-DQA1; rs601006; P=2.52×10(-11); odds ratio, 4.0; 95% CI, 3.57-4.43), although the set of single-nucleotide polymorphisms was different from that implicated among late-onset cases.

Conclusions And Relevance: Our genetic data provide insights into aberrant cellular mechanisms responsible for this prototypical autoimmune disorder. They also suggest that clinical trials of immunomodulatory drugs related to CTLA4 and that are already Food and Drug Administration approved as therapies for other autoimmune diseases could be considered for patients with refractory disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1001/jamaneurol.2014.4103DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4856525PMC
April 2015

T cell repertoire in DQ5-positive MuSK-positive myasthenia gravis patients.

J Autoimmun 2014 Aug 4;52:113-21. Epub 2014 Jan 4.

General Pathology Institute, Università Cattolica del Sacro Cuore, Largo F. Vito, 1, 00168 Rome, Italy. Electronic address:

Myasthenia gravis (MG) is a prototypical antibody-mediated disease characterized by muscle weakness and fatigability. Serum antibodies to the acetylcholine receptor and muscle-specific tyrosine kinase receptor (MuSK) are found in about 85% and 8% of patients respectively. We have previously shown that more than 70% of MG patients with MuSK antibodies share the HLA DQ5 allele. The aim of the present study was to analyze the T cell receptor (TCR) repertoire specific for recombinant human MuSK protein. We used the CDR3 TRBV-TRBJ spectratyping (immunoscope) to analyze the T cell response to MuSK from 13 DQ5+ MuSK-MG patients and from 7 controls (six DQ5+ MuSK negative subjects and one DQ5- DQ3+ MuSK positive patient). DQ5+ MuSK-MG patients but not controls used a restricted set of TCR VJ rearrangements in response to MuSK stimulation. One semiprivate (TRBV29-TRBJ2.5) rearrangement was found in 5/13 patients, while 4 other semiprivate (one in TRBV28-TRBJ2.1 and in TRBV3-TRBJ1.2, and two in TRBV28-TRBJ1.2) rearrangements were differently shared by 4/13 patients each and were absent in controls. When we sequenced the TRBV29-TRBJ2.5 rearrangement, we obtained 26 different sequences of the expected 130 bp length from 117 samples of the 5 positive patients: two common motifs GXGQET/TEHQET were shared in 4 patients as semiprivate motifs. Thus, the MuSK-specific T-cell response appears to be restricted in DQ5+ MuSK-MG patients, with a semiprivate repertoire including a common motif of TRBV29. This oligoclonal restriction of T cells will allow the identification of immunodominant epitopes in the antigen, providing therefore new tools for diagnosis and targeted therapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jaut.2013.12.007DOI Listing
August 2014

Association of the DNMT3B -579G>T polymorphism with risk of thymomas in patients with myasthenia gravis.

PLoS One 2013 19;8(11):e80846. Epub 2013 Nov 19.

Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy.

Increasing evidence suggests a contribution of epigenetic processes in promoting cancer and autoimmunity. Myasthenia gravis (MG) is an autoimmune disease mediated, in approximately 80% of the patients, by antibodies against the nicotinic acetylcholine receptor (AChR+). Moreover, epithelial tumours (thymomas) are present in about 10-20% of the patients, and there is indication that changes in DNA methylation might contribute to the risk and progression of thymomas. However, the role of epigenetics in MG is still not completely clarified. In the present study we investigated if a common polymorphism (-579G>T: rs1569686) in the promoter of the DNMT3B gene coding for the DNA methyltransferase 3B, an enzyme that mediates DNA methylation, increases the risk to develop MG or MG-associated thymomas. The study polymorphism was selected based on recent reports and a literature meta-analysis suggesting association with increased risk of various types of cancer. We screened 324 AChR+ MG patients (140 males and 184 females, mean age 56.0 ± 16.5 years) and 735 healthy matched controls (294 males and 441 females, mean age 57.3 ± 15.6 years). 94 of the total MG patients had a thymoma. While there was no association with the whole cohort of MG patients, we found a statistically significant association of the DNMT3B-579T allele (OR = 1.51; 95% CI=1.1-2.1, P = 0.01) and the TT homozygous genotype (OR = 2.59; 95% CI=1.4-4.9, P = 0.006) with the risk of thymoma. No association was observed in MG patients without thymoma, even after stratification into clinical subtypes. Present results suggest that the DNMT3B-579T allele might contribute to the risk of developing thymoma in MG patients, particularly in homozygous TT subjects.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0080846PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3834310PMC
August 2014

Management challenges in muscle-specific tyrosine kinase myasthenia gravis.

Ann N Y Acad Sci 2012 Dec;1274:86-91

Institute of Neurology, Catholic University, Rome, Italy.

Myasthenia gravis with antibodies to muscle-specific tyrosine kinase (MuSK-MG) is generally considered a severe disease because of the associated weakness distribution with prevalent involvement of bulbar muscles and a rapidly progressive course and early respiratory crises. Its treatment can be unrewarding, owing to poor response to acetylcholinesterase inhibitors in most patients, disease relapses in spite of high-dose immunosuppression, and development of permanent bulbar weakness. High-dose prednisone plus plasma exchange is the recommended approach for treating rapidly progressive bulbar weakness. In the disease management, oral steroids proved effective, plasma exchange produced marked, albeit short-term, improvement, while conventional immunosuppressants were comparatively less effective. Rituximab is a promising treatment for refractory MuSK-MG; in uncontrolled studies, nearly all treated patients achieved significant improvement with substantial decrease of medication. It is yet to be clarified whether the early use of rituximab could prevent the permanent bulbar weakness, which constitutes a relevant disability in these patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1749-6632.2012.06781.xDOI Listing
December 2012

PTPN22 and myasthenia gravis: replication in an Italian population and meta-analysis of literature data.

Neuromuscul Disord 2012 Feb 24;22(2):131-8. Epub 2011 Dec 24.

Institute of General Pathology, Catholic University, Largo Francesco Vito 1, 00168 Rome, Italy.

Polymorphisms in PTPN22 are associated with many autoimmune diseases; while rs2476601 is supposed to play a major role, other experimental data suggest that rs2488457 may be even more important. Results in myasthenia gravis are controversial. In 356 Italian myasthenic patients and 439 controls genotyped for both polymorphisms, we found that rs2476601 was not associated with myasthenia, presence of autoantibodies, thymus pathology, sex or onset age unlike previous studies on other European populations (confirmed by the present meta-analysis). On the other hand, while rs2488457 was not associated with myasthenia or thymus pathology, we found a correlation of rs2488457 with low autoantibody titers and a trend of association with a less severe disease. Both polymorphisms were in tight linkage disequilibrium in controls, not in patients. Our results suggest that SNPs in this gene different from rs2476601, and/or epigenetic interactions, could play a greater role.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.nmd.2011.09.003DOI Listing
February 2012

Anti-acetylcholinesterase antibodies associate with ocular myasthenia gravis.

J Neuroimmunol 2010 Jan 26;218(1-2):102-6. Epub 2009 Nov 26.

Institute of General Pathology, Catholic University, 00168 Rome, Italy.

In MG, anti-AChR or anti-MuSK abs impair neuromuscular transmission. Partial inhibition of AChE can ameliorate symptoms, while a complete block causes a cholinergic blockade. We found anti-AChE abs in 115/240 MG patients, with no correlation with sex, age at onset, thymus pathology, presence of anti-AChR or anti-MuSK antibodies. We found a correlation with the ocular form of the disease, and with milder forms of MG not requiring immunosuppressants; moreover, when we considered only those patients who were off AChEI therapy, we found that ocular patients were positive for anti-AChE abs, while generalized patients were negative. According to an experimental model, we hypothesize that anti-AChE abs could contribute to ptosis through an inhibition of the sympathetic innervation of the tarsal muscle.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jneuroim.2009.11.004DOI Listing
January 2010

Response to therapy in myasthenia gravis with anti-MuSK antibodies.

Ann N Y Acad Sci 2008 ;1132:76-83

Department of Neurosciences, Catholic University, Largo F. Vito 1, 00168 Rome, Italy.

Myasthenia gravis (MG) with antibodies against the muscle-specific tyrosine kinase (MuSK abs) is often a severe disease requiring aggressive treatment. Various immunosuppressive (IS) regimens have been employed; the efficacy of plasma exchange is unanimously recognized, while the indication for thymectomy is controversial. We evaluated the response to therapy in 57 MuSK-positive patients (12 M/45 F) comparing our experience with other authors' results. Disease severity and response to treatment were graded according to MG Foundation of America; follow-up ranged from 0.5-29 years. Owing to both MG severity and the unsatisfactory response to cholinesterase inhibitors, most patients (54/57) needed IS treatment, and 35 received one or more courses of plasma exchange and intravenous immunoglobulin. At the end of follow-up, the rate of complete remission was 8.8%, and IS treatment had been withdrawn in only 10/54 patients. The extent of therapeutic response varied considerably. With conventional IS therapy (prednisone alone or in combination with azathioprine or cyclosporine), most patients achieved good control of their disease, but 30% of them were left with permanent facial and bulbar weakness. In patients with refractory disease, the use of mycophenolate mofetil and rituximab proved very effective, as also reported by other authors. In our and others' experience, MuSK-positive MG markedly improves with IS therapy, although, in comparison with the AChR-positive disease, it is characterized by a lower remission rate, as a higher proportion of patients remain dependent on treatment. Thymectomy is mostly considered scarcely effective; however, at present, no firm conclusions can be drawn on its role in the treatment of this form of MG.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1196/annals.1405.012DOI Listing
September 2008

IL-6 regulates MCP-1, ICAM-1 and IL-6 expression in human myoblasts.

J Neuroimmunol 2008 May 8;196(1-2):41-8. Epub 2008 Apr 8.

Institute of General Pathology, Università Cattolica, L.go F. Vito 1, 00168 Roma, Italy.

The inflammatory reaction in autoimmune polymyositis and rejection of transplanted myoblasts is characterized by mononuclear cell infiltration. In other settings monocytes are locally recruited by an IL-6-induced IL-8-to-MCP-1 switch. IL-6, upon binding to soluble gp80 (sIL-6R), can interact with membrane-bound ubiquitously expressed gp130 and activate virtually all cells (transsignaling). We found that human myoblasts could use transsignaling to produce IL-6, MCP-1 and ICAM-1; the addition of sIL-6R, binding to IL-1beta-induced IL-6, greatly increases IL-6 production. These in vitro data support the hypothesis that locally secreted IL-6 can target monocyte chemotaxis and leukocytes trafficking through an IL-6, MCP-1 and ICAM-1 modulation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jneuroim.2008.02.005DOI Listing
May 2008

IL-6-deficient mice show impaired inflammatory response in a model of myosin-induced experimental myositis.

J Neuroimmunol 2006 Jul 24;176(1-2):9-15. Epub 2006 May 24.

Institute of General Pathology, Catholic University, Largo F. Vito 1, 00168 Rome, Italy.

Inflammatory/immune reactions against muscle cells are responsible for the damage in idiopathic inflammatory myopathies. We investigated the role of IL-6, a cytokine known to contribute to local leukocyte accumulation, in a model of myosin-induced experimental myositis. After injection of rabbit myosin in CFA/pertussis toxin, normal mice develop clinically evident muscle deficit and damage, as demonstrated by myofiber necrosis and leukocyte infiltration, while IL-6-deficient mice have no clinical or histological signs of muscle damage. This study evidences that selective deficiency of IL-6 directly or indirectly hinders the local inflammatory response and its harmful effects in this model of muscle damage.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jneuroim.2006.03.026DOI Listing
July 2006

Identification of disease-specific autoantibodies in seronegative myasthenia gravis.

Ann N Y Acad Sci 2003 Sep;998:356-8

Institute of General Pathology, Catholic University, 00168 Rome, Italy.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1196/annals.1254.041DOI Listing
September 2003

Clinical correlates with anti-MuSK antibodies in generalized seronegative myasthenia gravis.

Brain 2003 Oct 23;126(Pt 10):2304-11. Epub 2003 Jun 23.

Department of Neuroscience, Catholic University, Roma, Italy.

The term seronegative myasthenia gravis (SNMG) refers to the generalized disease without detectable anti-acetylcholine receptor (anti-AChR) antibodies. In these patients, IgG antibodies against the muscle-specific kinase (MuSK) have been described, which reduced agrin-induced AChR clustering in vitro. We have assayed anti-MuSK antibodies in 78 patients with SNMG, who have been followed for many years in our Institution. Here we describe the clinical phenotype of the 37 patients whose results were positive on this assay. MG with anti-MuSK antibodies was characterized by a striking prevalence of female patients (eight men and 29 women). Age of onset ranged from 6 to 68 years, with 56.8% of patients presenting under 40 years of age. All these patients shared a similar pattern of muscle weakness, with prevalent involvement of cranial and bulbar muscles and a high frequency of respiratory crises; the involvement of limb muscles was comparatively less severe and inconsistent. Single-fibre-EMG confirmed the most sensitive examination in the EMG diagnosis of MuSK-positive disease, while, owing to weakness topography, repetitive nerve stimulation in limb muscles was diagnostic in 56.8% of cases. The effect of edrophonium (or neostigmine) injection was equivocal or negative in 11 of 37 patients (29.7%), and the response to oral pyridostigmine was even more unsatisfactory, ranging from mild benefit to overt intolerance. In thymectomized patients, thymus was normal for age or atrophied, and no benefit from surgery was noticed. Thirty-five of 37 patients were given immunosuppressive therapy and 22 received plasma-exchange. The course of the disease was often characterized by periodic exacerbation phases requiring hospitalization and even assisted ventilation; plasma-exchange produced marked improvement in these cases. At the end of the observation period, most patients, although improved, were still symptomatic, having developed permanent facial and pharyngeal weakness together with some atrophy of facial muscles. MuSK-negative disease was comparatively more heterogeneous. Most patients were affected with mild to moderate symptoms and responded well to pharmacological treatment; however, a few subjects in this group had severe refractory disease, poorly responsive to both acetylcholinesterase inhibitors and immunosuppressants.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/brain/awg223DOI Listing
October 2003

TGF-beta 1 and IL-10 modulate IL-1 beta-induced membrane and soluble ICAM-1 in human myoblasts.

J Neuroimmunol 2003 Jan;134(1-2):151-7

Institute of General Pathology, Catholic University, Largo Francesco Vito 1, 00168 Rome, Italy.

We have previously shown that interleukin (IL)-1 beta and other inflammatory cytokines are able to induce the expression of membrane and soluble intercellular adhesion molecule (ICAM)-1 on human myoblasts. In this paper we found that IL-10 and transforming growth factor (TGF)-beta 1 are able to prevent IL-1 beta-induced membrane and soluble ICAM-1 protein expression on human myoblasts, with different time courses. The effect of both cytokines is associated to a reduction in ICAM-1 mRNA. Our findings suggest that IL-10 and TGF-beta 1 are able to influence the inflammatory process in muscle tissue at least in part by means of control of membrane and soluble ICAM-1.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/s0165-5728(02)00399-5DOI Listing
January 2003

Anti-p110 autoantibodies identify a subtype of "seronegative" myasthenia gravis with prominent oculobulbar involvement.

Lab Invest 2002 Sep;82(9):1139-46

Institute of General Pathology, Catholic University, Rome, Italy.

Myasthenia gravis (MG) is an autoimmune disease characterized by muscle weakness and pathogenetic autoantibodies directed against the nicotinic acetylcholine receptor (seropositive myasthenia gravis; SPMG). Nearly 15% to 20% of MG patients do not have these antibodies (seronegative myasthenia gravis; SNMG), but several evidence indicate that these patients have circulating pathogenic autoantibodies directed against other muscle antigens. Using the TE671 rhabdomyosarcoma cell line as an antigen source, we analyzed sera from 63 SNMG and 26 SPMG patients and 26 healthy blood donors by FACS analysis. We found that 40 of 63 SNMG patients and only 1 of 26 SPMG patients had IgG binding to the TE671 cell line. None of the sera bound to the unrelated MRC5 cell line. To identify the antigen, we analyzed sera immunoreactivity in more detail by immunoprecipitation of biotinylated membrane proteins from TE671 cells. When the immunoprecipitated proteins were separated by SDS-PAGE electrophoresis and then transferred to nitrocellulose membranes, we found that SNMG IgG identify a band corresponding to a protein with a molecular weight of 110 kDa (P110), which is not recognized by seropositive MG sera. This anti-P110 immunoreactivity is significantly associated with a distinct clinical picture characterized by a prominent involvement of ocular and bulbar muscles, with frequent respiratory problems (p < 0.005), and is recognized by a specific antimuscle specific kinase (MuSK) antiserum. In a recent article, the presence of anti-MuSK antibodies was described in SNMG. Our results confirm the presence of these antibodies in SNMG and suggest that anti-P110/MuSK autoantibodies identify a subtype of SNMG in which the different pathogenesis induces the distinct clinical picture.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/01.lab.0000028144.48023.9bDOI Listing
September 2002