Claudia Giannotta

How useful are anti-neural IgM antibodies in the diagnosis of chronic immune-mediated neuropathies?

Antibodies against several neural antigens have been associated with different chronic immune-mediated neuropathies but their practical clinical relevance remains unclear. To determine the possible diagnostic usefulness of these antibodies we reviewed the clinical correlate of IgM antibodies to the myelin-associated glycoprotein (MAG), sulfatide, the gangliosides GM1, GM2, GD1a and GD1b in 539 consecutive patients examined for neuropathy or related diseases in our Neuropathy Clinics and tested for these antibodies in our laboratory since 1985. 302 patients (56%) had an established diagnosis of definite or possible chronic immune-mediated neuropathy while 237 had a neuropathy of non-immune-mediated origin or of unknown aetiology or a closely related disease. Antibodies to one or more antigen were more frequent (chi(2)=63.32; p<0.00001) in patients with chronic immune-mediated neuropathy (37.7%) than with other neuropathy or related diseases (7.2%) and their presence was associated in 87% of the patients with an immune-mediated neuropathy, incrementing by 31% the probability of having this form. Testing for MAG permitted to identify 24.8% of patients with an immune-mediated neuropathy, GM1 an additional 9.9%, while GM2, GD1b, GD1a and sulfatide altogether an additional 3% of the patients. Concerning clinical correlations, all 75 patients with anti-MAG IgM had neuropathy and IgM monoclonal gammopathy (PN+IgM) with a positive predictive value for this neuropathy of 100%. A similarly high predictive value for neuropathy (91.4%) was observed among 269 patients with IgM monoclonal gammopathy including 103 patients without neuropathy. Anti-sulfatide IgM, though rare, were also significantly and constantly associated with PN+IgM and permitted to identify few patients not bearing anti-MAG IgM. Anti-GM1 IgM were significantly associated with multifocal motor neuropathy (MMN) (29.2%) but where also found in a few patients with other immune or non-immune neuropathies or related diseases with a positive predictive value for MMN of 25.5%. Anti-GM2 IgM were also significantly associated with MMN and increased the sensitivity (36.2%) for MMN obtained with anti-GM1 IgM only, without affecting its specificity and positive predictive value. Anti-GD1a, GD1b, though not significantly more frequent in patients with immune-mediated neuropathy, were associated in 80 to 100% of patients with these neuropathies. In conclusion anti-neural IgM antibodies may help in identifying patients with a chronic immune-mediated neuropathy, even if only anti-MAG and anti-sulfatide IgM appear to be strictly associated with a definite clinical syndrome.

SERUM VEGF LEVELS IN POEMS SYNDROME AND IN IMMUNE-MEDIATED NEUROPATHIES

POEMS syndrome is a multiorgan disorder defined by the association of polyneuropathy (P), organomegaly (O), endocrinopathy (E), M-protein (M), and skin changes (S).1 Serum levels of vascular endothelial growth factor (VEGF) are often markedly elevated in patients with POEMS,2-5 but not with other monoclonal gammopathies.2,4,5 Few patients with other neuropathies have been examined,2-5,6 so that the specificity of elevated VEGF levels for POEMS among patients with neuropathy remains unclear, especially when levels are moderately increased. ### Methods. We measured serum VEGF in 161 patients with neuropathy or related syndromes consecutively recruited and tested for antinerve antibodies at our neuropathy clinic. Six patients had POEMS diagnosed in the presence of at least four of the five features of POEMS, 13 had Guillain-Barre syndrome (GBS), 33 had chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) with no other feature of POEMS, 13 had multifocal motor neuropathy (MMN), 19 had neuropathy associated with IgM monoclonal gammopathy of undetermined significance (MGUS) (PN+IgM) with anti-MAG or anti-sulfatide IgM, 49 had neuropathies of other (diabetes in 8, multiple myeloma or lymphoma in 8, systemic vasculitis or other rheumatic diseases in 5, amyloidosis in 3, toxic in 2, inherited in 2, paraneoplastic and small fiber neuropathy in 1 each) or of undetermined causes (19) (other PN), and 28 had amyotrophic lateral sclerosis (ALS). We also tested 21 patients with MGUS or multiple myeloma (MM) without neuropathy (MGUS/MM), and 22 …

Sensitivity and predictive value of anti-GM1/galactocerebroside IgM antibodies in multifocal motor neuropathy

Background Increased titres of serum IgM antibodies to GM1 ganglioside are often associated with multifocal motor neuropathy (MMN). Testing for IgM antibodies to other antigens including GM2, the mixture of GM1 and galactocerebroside (GM1/GalC) and the disulfated heparin disaccharide NS6S were reported to increase the sensitivity of antibody testing in MMN even if it is unclear whether the specificity and positive (PPV) or negative predictive value (NPV) for MMN were also affected. Methods We measured IgM antibodies to GM1, GM2, galactocerebroside, GM1/GalC and NS6S in 40 consecutive patients with MMN and 142 controls with other neuropathies or related diseases and compared their sensitivity, specificity and PPV for MMN. Results With the only exception of anti-GM2 and, partially, anti-NS6S antibodies, IgM antibodies to the antigens tested were more frequent in MMN than in controls. Increased titres of anti-GM1 IgM were found in 48% of MMN patients with a specificity of 93% and PPV for MMN of 66%. Anti-GM1/GalC antibodies were present in all anti-GM1 positive MMN patients and in 11 additional patients (28%) with MMN raising the sensitivity of antibody testing to 75%. The specificity (85%) and PPV (59%) for MMN was, however, moderately reduced compared to anti-GM1 IgM, even if they rose with increasing anti-GM1/GalC titres. IgM antibodies to GM2, NS6S and galactocerebroside were found in 8%, 23% and 60% of MMN patients but had a low specificity and PPV for MMN. Conclusions Testing for anti-GM1/GalC IgM significantly increased the sensitivity of antibody testing in MMN compared to anti-GM1 alone (p=0.021) and may represent a preferred option for GM1 reactivity testing in MMN.

Efficacy of lenalidomide plus dexamethasone for POEMS syndrome relapsed after autologous peripheral stem-cell transplantation†

POEMS syndrome is a rare paraneoplastic condition associated to an underlying plasmacellular dyscrasia. The pathogenesis of POEMS is poorly understood, but overproduction of VEGF, probably secreted by clonal plasma cells, is thought to be responsible for the signs and symptoms of the syndrome, and it seems to be useful for the monitoring of the response to therapy. At present, an effective therapeutic option for the patients is represented by autologous peripheral blood stem-cell transplantation (aPBSCT), although relapses have been described, and there is an important morbidity associated with this procedure. Before the implementation of aPBSCT, the clinical course of POEMS syndrome was characterized by progressive polyneuropathy potentially leading to death for respiratory failure. Given the high serum and plasma levels of VEGF observed in POEMS patients, the use of anti-angiogenetic drugs such as thalidomide and lenalidomide and other drugs with anti-VEGF and anti-TNF effect such as bortezomib have been considered to treat this syndrome. There are evidences of lenalidomide benefit in both front-line and previously treated patients, but scanty data are available about its use for relapse after aPBSCT. Here, we report the successful use of lenalidomide in a patient who relapsed after aPBSCT.

Testing for anti-glycolipid IgM antibodies in chronic immune-mediated demyelinating neuropathies.

Antibodies to several nerve antigens have been reported in patients with chronic immune‐mediated demyelinating neuropathies including chronic inflammatory demyelinating polyradiculoneuropathy, multifocal motor neuropathy, and IgM paraproteinemic demyelinating polyneuropathy. The association of some reactivities with specific neuropathies, such as IgM antibodies to the myelin‐associated glycoprotein in neuropathy associated with IgM monoclonal gammopathy, permitted to cast some light in their pathogenetic mechanisms and introduced new useful tools in their diagnosis. Other antibodies have been variably associated with other forms of neuropathy or with neuropathy itself, casting some doubts on their diagnostic relevance in the workout of these neuropathies. This is particularly true for IgM antibodies to glycolipids, including ganglioside and sulfatides, whose possible role in immune‐mediated neuropathies is still debated and will be here reviewed.

Diagnostics of autoimmune encephalitis associated with antibodies against neuronal surface antigens

This document presents the guidelines for testing antibodies against neuronal surface antigens that have been developed following a consensus process built on questionnaire-based surveys, internet contacts, and discussions at workshops of the sponsoring Italian Association of Neuroimmunology (AINI) congresses. Essential clinical information on autoimmune encephalitis associated with antibodies against neuronal surface antigens, indications and limits of testing for such antibodies, instructions for result interpretation, and an agreed laboratory protocol (Appendix A) are reported for the communicative community of neurologists and clinical pathologists.

Cerebrospinal fluid analysis and the determination of oligoclonal bands

This document presents the guidelines for the cerebrospinal fluid (CSF) analysis and the determination of oligoclonal bands (OCBs) as pivotal tests in neuroinflammatory pathologies of the central nervous system. The guidelines have been developed following a consensus process built on questionnaire-based surveys, internet contacts, and discussions at workshops of the sponsoring Italian Association of Neuroimmunology (AINI) congresses. Essential clinical information on the pathologies in which the CSF analysis is indicated, and, particularly, on those characterized by the presence of OCBs in the intrathecal compartment, indications and limits of CSF analysis and OCB determination, instructions for result interpretation, and agreed laboratory protocols (Appendix) are reported for the communicative community of neurologists and clinical pathologists.

Diagnostics of anti-MAG antibody polyneuropathy

This document presents the guidelines for anti-myelin-associated glycoprotein (MAG) antibody testing that have been developed following a consensus process built on questionnaire-based surveys, internet contacts, and discussions at workshops of sponsoring Italian Association of Neuroimmunology (AINI) congresses. The main clinical information on anti-MAG antibody polyneuropathy, indications and limits of anti-MAG antibody testing, instructions for result interpretation, and an agreed laboratory protocol (Appendix) are reported for the communicative community of neurologists and clinical pathologists.

Diagnostics of dysimmune peripheral neuropathies

This document presents the guidelines for anti-ganglioside antibody testing that have been developed following a consensus process built on questionnaire-based surveys, internet contacts, and discussions at workshops of the sponsoring Italian Association of Neuroimmunology (AINI) congresses. Main clinical information on dysimmune peripheral neuropathies, indications and limits of anti-ganglioside antibody testing, instructions for result interpretation, and an agreed laboratory protocol (Appendix) are reported for the communicative community of neurologists and clinical pathologists.

Diagnostics of paraneoplastic neurological syndromes

This document presents the guidelines for onconeural antibody testing that have been developed following a consensus process built on questionnaire-based surveys, internet contacts, and discussions at workshops of the sponsoring Italian Association of Neuroimmunology (AINI) congresses. Essential clinical information on paraneoplastic neurological syndromes, indications and limits of onconeural antibody testing, instructions for result interpretation, and an agreed laboratory protocol (Appendix) are reported for the communicative community of neurologists and clinical pathologists.