Immunotherapy-based regimen in anti-MAG neuropathy: results in 45 patients

Pathophysiology and Treatments of Complications of Waldenström's Macroglobulinemia

Waldenstrom's macroglobulinemia (WM) or lymphoplasmacytic lymphoma is a B-cell malignancy characterized by lymphoplasmacytic cells in the bone marrow that secrete high amounts of immunoglobulin (Ig) M. The large pentameric structure of IgM leads to a variety of unique complications in WM, such as hyperviscosity syndrome, cryoglobulinemia and sensory neuropathy. Furthermore, malignant cells can infiltrate the central nervous system and lead to a variety of neurological complications, also known as Bing Neel Syndrome. Because of the unique pathophysiology of WM and these complications, their diagnostic work up and treatment regimens vary greatly. Given the rarity of the disease and their complications, there are little to no randomized controlled trials regarding treatments of these complications and, therefore, suggested treatment regimens are usually based on observational studies. In this case series, we will present three cases of WM, each with their own unique complication, and discuss the pathophysiology along with current and future treatment options for each of the complications presented.

Uncommon Presentation of IgM Monoclonal Gammopathy of Undetermined Significance (MGUS) and Anti-Myelin-Associated Glycoprotein (MAG)-Associated Demyelinating Peripheral Neuropathy as Respiratory Failure: A Case Report

Monoclonal gammopathy of undetermined significance (MGUS) is a premalignant clonal plasma cell disorder characterized by monoclonal immunoglobulins and/or an abnormal free immunoglobulin light chain ratio. MGUS can be associated with immune-mediated neuropathies, including chronic inflammatory demyelinating neuropathy and its variants. Here, we report the case of a 76-year-old male who presented with progressive weakness, initially in the lower extremities and later including the upper extremities. Serum protein electrophoresis and immunofixation identified an IgM kappa monoclonal protein and further testing confirmed high titers of anti-myelin-associated glycoprotein (MAG) antibodies, leading to a diagnosis of anti-MAG-associated demyelinating peripheral neuropathy. The coexistence of MGUS and anti-MAG antibodies requires meticulous diagnosis and management, especially in patients who present with atypical symptoms of the disease.

When Waldenström macroglobulinemia hits the kidney: Description of a case series and management of a "rare in rare" scenario

BACKGROUND

Renal injury related to Waldenström macroglobulinemia (WM) occurs in approximately 3% of patients. Kidney biopsy is crucial to discriminate between distinct histopathological entities such as glomerular (amyloidotic and non-amyloidotic), tubulo-interstitial and non-paraprotein mediated renal damage. In this context, disease characterization, management, relationship between renal, and hematological response have been poorly explored. We collected clinical, genetic and laboratory data of seven cases of biopsy-proven renal involvement by WM managed at our academic center and focused on three cases we judged paradigmatic discussing their histopathological patterns, clinical features, and therapeutic options.

CASE

In this illustrative case series, we confirm that serum creatinine levels and 24 h proteinuria are parameters that when altered should prompt the clinical suspicion of WM-related renal involvement, even if at present there are not precise cut-off levels recommending the execution of a renal biopsy. In our series AL Amyloidosis (n = 3/7) and tubulo-interstitial infiltration by lymphoma cells (n = 3/7) were the two more represented entities. BTKi did not seem to improve renal function (Case 1), while bortezomib-based regimens demonstrated a beneficial activity on the hematological and organ response, even when used as second-line therapy after chemoimmunotherapy (Case 3) and also with coexistence of anti-MAG neuropathy (Case 2). In case of poor response to bortezomib, standard chemoimmunotherapy (CIT), such as rituximab-bendamustine, represents an effective option (Case 1, 6, and 7). In our series, CIT generates durable responses more frequently in cases with amyloidogenic renal damage (Case 1, 5, and 7).

CONCLUSION

In this illustrative case series, we confirm that serum creatinine levels and 24 h proteinuria are parameters that when altered should prompt the clinical suspicion of WM-related renal involvement, even if at present there are not precise cut-off levels recommending the execution of a renal biopsy. Studies with higher numerosity are needed to better clarify the pathological and clinical features of renal involvement during WM and to determine the potential benefit of different therapeutic regimens according to the histopathological subtypes.

Polyneuropathy Associated with IgM Monoclonal Gammopathy; Advances in Genetics and Treatment, Focusing on Anti-MAG Antibodies

With increasing age, the chances of developing either MGUS or polyneuropathy increase as well. In some cases, there is a causative relationship between the IgM M-protein and polyneuropathy. In approximately half of these cases, IgM targets the myelin-associated glycoprotein (MAG). This results in chronic polyneuropathy with slowly progressive, predominantly sensory neurological deficits and distally demyelinating features in nerve conduction studies. Despite the disease being chronic and developing slowly, it can cause considerable impairment. We reviewed English medical publications between 1980 and May 2022 on IgM gammopathy-associated polyneuropathy, with special attention to studies addressing the pathophysiology or treatment of anti-MAG polyneuropathy. Treatment options have been limited to a temporizing effect of intravenous immunoglobulins in some patients and a more sustained effect of rituximab but in only 30 to 55 percent of patients. An increase in our knowledge concerning genetic mutations, particularly the MYD88L265P mutation, led to the development of novel targeted treatment options such as BTK inhibitors. Similarly, due to the increasing knowledge of the pathophysiology of anti-MAG polyneuropathy, new treatment options are emerging. Since anti-MAG polyneuropathy is a rare disease with diverse symptomatology, large trials with good outcome measures are a challenge.

Immunochemotherapy versus rituximab in anti-myelin-associated glycoprotein neuropathy: A report of 64 patients

Monoclonal immunoglobulin M (IgM) anti-myelin-associated glycoprotein (MAG) neuropathy is a rare disabling condition, most commonly treated with rituximab monotherapy (R), which leads to neurological improvement in only 30%-50% of patients. The combination of rituximab plus chemotherapy has been proven to improve the level of responses. We studied the outcomes of anti-MAG neuropathy patients treated either by R, or by immunochemotherapy (ICT) in our centre, focusing on the incidence of the first neurological response evaluated by the modified Rankin scale (mRS). From 2011 to 2018, 64 patients were studied: 34 were treated with R and 30 with ICT. According to our treatment decision-making process, the median mRS was higher in the ICT group (mRS 2) than in the R group (mRS 1). At one year, improvements of the mRS rates were 46% and 18% in the ICT and R groups of patients respectively, with median times to response of eight and 13 months (p = 0.023). Adverse effects were higher in the ICT group: 62% vs 15% (p ˂ 0.01), all grades included. One secondary acute leukaemia occurred five years after treatment with ICT. In conclusion, ICT may be used as a valid option for patients with rapidly progressive and/or severe anti-MAG neuropathy symptoms.

From Biology to Treatment of Monoclonal Gammopathies of Neurological Significance

Monoclonal gammopathy and peripheral neuropathy are common diseases of elderly patients, and almost 10% of patients with neuropathy of unknown cause have paraprotein. However, growing evidence suggests that several hematological malignancies synthesize and release monoclonal proteins that damage the peripheral nervous system through different mechanisms. The spectrum of the disease varies from mild to rapidly progressive symptoms, sometimes affecting not only sensory nerve fibers, but also motor and autonomic fibers. Therefore, a multidisciplinary approach, mainly between hematologists and neurologists, is recommended in order to establish the correct diagnosis of monoclonal gammopathy of neurological significance and to tailor therapy based on specific genetic mutations. In this review, we summarize the spectrum of monoclonal gammopathies of neurological significance, their distinctive clinical and neurophysiological phenotypes, the most relevant pathophysiological events and new therapeutic approaches.

Decrease in Serum Anti-MAG Autoantibodies Is Associated With Therapy Response in Patients With Anti-MAG Neuropathy: Retrospective Study

Background and Objectives

The objective of the retrospective analysis was to test the hypothesis that changes in serum anti-myelin-associated glycoprotein (MAG) autoantibodies are associated with clinical response to immunotherapy in patients with anti-MAG neuropathy.

Methods

As of January 29, 2020, we used anti-myelin-associated glycoprotein-related search strings in the Medline database to identify studies that provided information on anti-MAG immunoglobulin M (IgM) autoantibodies and clinical outcomes during immunotherapies. The relative change in anti-MAG IgM titers, paraprotein levels, or total IgM was determined before, during, or posttreatment, and the patients were assigned to “responder,” “nonresponder,”’ or “acute deteriorating” category depending on their clinical response to treatment. The studies were qualified as “supportive” or “not supportive” depending on the percentage of patients exhibiting an association between relative change of anti-MAG antibody titers or levels and change in clinical outcomes.

Results

Fifty studies with 410 patients with anti-MAG neuropathy were included in the analysis. Forty studies with 303 patients supported the hypothesis that a “responder” patient had a relative reduction of anti-MAG antibody titers or levels that is associated with clinical improvements and “nonresponder” patients exhibited no significant change in anti-MAG IgM antibodies. Six studies with 93 patients partly supported, and 4 studies with 26 patients did not support the hypothesis.

Discussion

The retrospective analysis confirmed the hypothesis that a relative reduction in serum anti-MAG IgM antibodies is associated with a clinical response to immunotherapies; a sustained reduction of at least 50% compared with pretreatment titers or levels could be a valuable indicator for therapeutic response.

Managing complications secondary to Waldenström's macroglobulinemia

Introduction: Waldenström's macroglobulinemia (WM) is a rare lymphoma characterized by the accumulation of IgM-secreting lymphoplasmacytic cells in the bone marrow and other organs. Clinical sequelae relate to direct tissue infiltration by malignant cells but also to the physicochemical and immunological properties of the monoclonal IgM, resulting in a variety of disease-related complications.Areas covered: This narrative review, following a thorough Pubmed search of pertinent published literature, discusses complications secondary to WM, related to direct tumor infiltration, monoclonal IgM circulation, and deposition, as well as other less common ones. The description and pathophysiology of these complications were described together with their specific management strategies and in the context of available treatment options for WM (anti-CD20 monoclonal antibody-based combinations, proteasome inhibitors, BTK inhibitors, and other emerging ones).Expert opinion: The availability of many novel, active and less toxic regimens for the treatment of WM allows the management of the disease with strategies that depend on clinical presentation and disease-related complications, age, toxicity considerations, and presence of comorbidities.

The evaluation and management of monoclonal gammopathy of renal significance and monoclonal gammopathy of neurological significance

Despite the benign nature of monoclonal gammopathy of undetermined significance (MGUS), mounting data are associating MGUS with the development of organ dysfunction, specifically monoclonal gammopathy of renal significance (MGRS) and monoclonal gammopathy of neurological significance (MGNS), which could be associated with substantial morbidity. Emerging evidence suggests that patients with MGRS and MGNS could benefit from treatments used for myeloma, Waldenström macroglobulinemia, or chronic lymphocytic leukemia, depending on the underlying pathology. However, the treatment of MGRS and MGNS is not standardized, and potentially effective therapies might not be reimbursed because these conditions do not formally meet the criteria for malignant processes. The present review aims at establishing standards for the evaluation and management of MGRS and MGNS, which can facilitate the diagnosis of and provide therapeutic options for treating practitioners and patients affected by these conditions. The careful design and execution of clinical trials for patients with MGRS and MGNS are positively encouraged.

CANOMAD: a neurological monoclonal gammopathy of clinical significance that benefits from B-cell-targeted therapies

CANOMAD (chronic ataxic neuropathy, ophthalmoplegia, immunoglobulin M [IgM] paraprotein, cold agglutinins, and disialosyl antibodies) is a rare syndrome characterized by chronic neuropathy with sensory ataxia, ocular, and/or bulbar motor weakness in the presence of a monoclonal IgM reacting against gangliosides containing disialosyl epitopes. Data regarding associated hematologic malignancies and effective therapies in CANOMAD are scarce. We conducted a French multicenter retrospective study that included 45 patients with serum IgM antibodies reacting against disialosyl epitopes in the context of evocating neurologic symptoms. The main clinical features were sensitive symptoms (ataxia, paresthesia, hypoesthesia; n = 45, 100%), motor weakness (n = 18, 40%), ophthalmoplegia (n = 20, 45%), and bulbar symptoms (n = 6, 13%). Forty-five percent of the cohort had moderate to severe disability (modified Rankin score, 3-5). Cold agglutinins were identified in 15 (34%) patients. Electrophysiologic studies showed a demyelinating or axonal pattern in, respectively, 60% and 27% of cases. All patients had serum monoclonal IgM gammopathy (median, 2.6 g/L; range, 0.1-40 g/L). Overt hematologic malignancies were diagnosed in 16 patients (36%), with the most frequent being Waldenström macroglobulinemia (n = 9, 20%). Forty-one patients (91%) required treatment of CANOMAD. Intravenous immunoglobulins (IVIg) and rituximab-based regimens were the most effective therapies with, respectively, 53% and 52% of partial or better clinical responses. Corticosteroids and immunosuppressive drugs were largely ineffective. Although more studies are warranted to better define the optimal therapeutic sequence, IVIg should be proposed as the standard of care for first-line treatment and rituximab-based regimens for second-line treatment. These compiled data argue for CANOMAD to be included in neurologic monoclonal gammopathy of clinical significance.

From pathogenesis to personalized treatments of neuropathies in hematological malignancies

The peripheral nervous system may be involved at any stage in the course of several hematological diseases, the most common being monoclonal gammopathies (of undetermined significance or malignant) or lymphomas. The underlying pathogenic mechanisms are different and therapies aim at targeting the dangerous either B-cell or plasma cell clones. Recently, high-throughput technologies, and next-generation sequencing have increased our knowledge of hematological diseases pathogenesis by the identification of somatic mutation affecting pivotal signaling pathways. Accordingly, new target therapies are used that may also be borrowed for treatment of neuropathies in hematological diseases.

How I treat Waldenström macroglobulinemia

Waldenström macroglobulinemia (WM) is an uncommon lymphoma characterized by the infiltration of the bone marrow by clonal lymphoplasmacytic cells that produce monoclonal immunoglobulin M (IgM). The disease may have an asymptomatic phase, or patients may present with symptoms and complications resulting from marrow or other tissue infiltration, or from physicochemical or immunological properties of the monoclonal IgM. Diagnosis of WM has been clearly defined, and genetic testing for somatic mutation of MYD88L265P is a useful tool for differential diagnosis from other conditions. Specific criteria that define symptomatic disease that needs treatment offer clinical guidance. The treatment of WM has evolved rapidly, with treatment options that include anti-CD20 monoclonal antibody-based combinations and BTK inhibitors. The choice of therapy is based on the need for rapid disease control, presence of specific disease complications, and patient's age. With the use of BTK inhibitors, the use of continuous therapy has been introduced as another option over fixed-duration chemoimmunotherapy. In this review, we focus on different clinical scenarios and discuss treatment options, based on the available data.

Native versus deglycosylated IgM in anti-MAG neuropathy: Correlation with clinical status - Study of 10 cases

BACKGROUND/PURPOSE

In anti-myelin associated glycoprotein (anti-MAG) neuropathies, there is evidence that anti-MAG antibodies are pathogenic but numerous studies report the absence or a weak correlation between the titers of these antibodies and disease course. In this study we assessed the relationships between MAG and glycosylated moieties located on Fc fragment of IgM anti-MAG.

MATERIAL AND METHODS

IgM were extracted from the serum of 8 patients with anti-MAG neuropathy and in 2 patients with anti-MAG antibodies without anti-MAG neuropathy. Anti-MAG activity was performed with pre- and post-deglycosylated IgM extracts using indirect immunofluorescence (IIF) and ELISA. Sera from 49 patients with IgM monoclonal gammopathy without neurological disease were tested as control group (CG). Results were compared to clinical scores. For 4 patients the affinity constant of IgM with MAG was analyzed pre- and post-deglycosylated, using surface plasmon resonance technology (SPR).

RESULTS

The relationships between MAG and glycosylated moieties of IgM anti-MAG were confirmed by kinetic and immunological assays. Deglycosylation resulted in a decrease in anti-MAG titers. Post-deglycosylation anti-MAG titers trended with changes in IgM titers and allowed quantifying anti-MAG antibodies without a saturation of the testing method. After deglycosylation, the titers better represented pathogenic activity and help to follow a given patient's clinical status prospectively. Six patients from CG (12.2%) had anti-MAG antibody titers over positive threshold: 1000 Bühlmann-Titer-Units (BTU) supporting the hypothesis of neutral intermolecular interactions between IgM and MAG. Deglycosylation allowed distinguishing infra clinical forms from neutral relationships forms, when the titers are weak but this assay remains essentially a diagnostic tool.

Anti-MAG antibodies in 202 patients: clinicopathological and therapeutic features

OBJECTIVE

To assess the clinicopathological and therapeutic features of patients with low (≥1000 to <10 000 Bühlmann Titre Units) (BTU), medium (10 000-70 000) or high (≥70 000) anti-myelin-associated glycoprotein (anti-MAG) antibody titres.

METHODS

We retrospectively and prospectively analysed standardised report forms and medical records of 202 patients from 14 neuromuscular centres.

RESULTS

Mean age at onset and mean time between symptom onset to last follow-up were respectively 62.6 years (25-91.4) and 8.4 years (0.3-33.3). Anti-MAG antibody titres at diagnosis were low, medium or high in 11%, 51% and 38% of patients. Patients presented with monoclonal gammopathy of undetermined significance in 68% of cases. About 17% of patients presented with 'atypical' clinical phenotype independently of anti-MAG titres, including acute or chronic sensorimotor polyradiculoneuropathies (12.4%), and asymmetric or multifocal neuropathy (3%). At the most severe disease stage, 22.4% of patients were significantly disabled. Seventy-eight per cent of patients received immunotherapies. Transient clinical worsening was observed in 12% of patients treated with rituximab (11/92). Stabilisation after rituximab treatment during the 7-12-month follow-up period was observed in 29% of patients. Clinical response to rituximab during the 6-month and/or 7-12-month follow-up period was observed in 31.5% of patients and correlated with anti-MAG titre ≥10 000 BTU.

CONCLUSION

Our study highlights the extended clinical spectrum of patients with anti-MAG neuropathy, which appears unrelated to antibody titre. Besides, it may also suggest beneficial use of rituximab in the early phase of anti-MAG neuropathy.

How we manage patients with Waldenström macroglobulinaemia

Waldenström macroglobulinaemia (WM) is a rare, indolent B-cell lymphoproliferative disorder characterized by cellular involvement in bone marrow and monoclonal IgM production. Symptoms can be related to cytopenias, tumoural involvement, or IgM-related disorders. Somatic mutations in the MYD88 gene have been described in the majority of WM cases. The mutation is responsible for a gain-of-function and induces activation of nuclear factor-κB, for DNA transcription and cell survival. It seems that MYD88 mutation is associated with better prognosis and better response to some treatment. Treatments are started when WM is symptomatic, following systematic biological and morphological assessments. Therapeutic choice depends on age, frailty and urgent efficacy need. In first line, the majority of patients are treated with monoclonal anti-CD20 antibody-based regimens combined with cytotoxic chemotherapy. Rituximab, cyclophosphamide and dexamethasone remain the most commonly used regimen with good safety. Nevertheless, increasing numbers of new drugs are becoming available or are in development. Proteasome inhibitors, such as bortezomib or carfilzmib, showed good and rapid responses. Bruton tyrosine kinase (BTK) inhibitor demonstrated excellent results and is now available for relapse/refractory disease or as first line for some patients. This review highlights the diagnostic procedures and therapeutic approaches in WM.

Investigation and management of IgM and Waldenström-associated peripheral neuropathies: recommendations from the IWWM-8 consensus panel

Paraproteinaemic neuropathies are a heterogeneous group of disorders most frequently associated with IgM monoclonal gammopathies including Waldenström macroglobulinaemia (WM). Their consequences are significant for affected patients, and their management challenging for their physicians. The variability in clinical presentation and time course hamper classification and management. The indications for invasive investigations such as cerebrospinal fluid analysis, nerve conduction tests and sensory nerve biopsies are unclear, and the optimum way to measure clinical response to treatment unknown. When to intervene and and how to treat, also present challenges to physicians. As part of its latest deliberations at the International Workshops on WM (IWWM) in London, UK (August 2014), the IWWM8 panel have proposed a consensus approach to the diagnosis and management of peripheral neuropathies associated with IgM monoclonal gammopathies, including WM. Importantly, a consensus regarding the use of clinical outcome measures and recommended models of care for this group of patients is discussed, as well as appropriate treatment interventions.

Immunotherapy in Peripheral Neuropathies

Immunotherapy has been investigated in a small subset of peripheral neuropathies, including an acute one, Guillain-Barré syndrome, and 3 chronic forms: chronic inflammatory demyelinating polyradiculoneuropathy, multifocal motor neuropathy, and neuropathy associated with IgM anti-myelin-associated glycoprotein. Several experimental studies and clinical data are strongly suggestive of an immune-mediated pathogenesis. Either cell-mediated mechanisms or antibody responses to Schwann cell, compact myelin, or nodal antigens are considered to act together in an aberrant immune response to cause damage to peripheral nerves. Immunomodulatory treatments used in these neuropathies aim to act at various steps of this pathogenic process. However, there are many phenotypic variants and, consequently, there is a significant difference in the response to immunotherapy between these neuropathies, as well as a need to improve our knowledge and long-term management of chronic forms.

How I treat Waldenström macroglobulinemia

Waldenström macroglobulinemia (WM) is a B-cell neoplasm manifested by the accumulation of clonal immunoglobulin (Ig)M-secreting lymphoplasmacytic cells. MYD88 and CXCR4 warts, hypogammaglobulinemia, infections, myelokathexis syndrome-like somatic mutations are present in >90% and 30% to 35% of WM patients, respectively, and impact disease presentation, treatment outcome, and overall survival. Familial predisposition is common in WM. Asymptomatic patients should be observed. Patients with disease-related hemoglobin <10 g/L, platelets <100 × 10(9)/L, bulky adenopathy and/or organomegaly, symptomatic hyperviscosity, peripheral neuropathy, amyloidosis, cryoglobulinemia, cold-agglutinin disease, or transformed disease should be considered for therapy. Plasmapheresis should be used for patients with symptomatic hyperviscosity and before rituximab for those with high serum IgM levels to preempt a symptomatic IgM flare. Treatment choice should take into account specific goals of therapy, necessity for rapid disease control, risk of treatment-related neuropathy, immunosuppression and secondary malignancies, and planning for future autologous stem cell transplantation. Frontline treatments include rituximab alone or rituximab combined with alkylators (bendamustine and cyclophosphamide), proteasome inhibitors (bortezomib and carfilzomib), nucleoside analogs (fludarabine and cladribine), and ibrutinib. In the salvage setting, an alternative frontline regimen, ibrutinib, everolimus, or stem cell transplantation can be considered. Investigational therapies under development for WM include agents that target MYD88, CXCR4, BCL2, and CD27/CD70 signaling, novel proteasome inhibitors, and chimeric antigen receptor-modified T-cell therapy.

[2013: what's new in inflammatory neuropathies]

Several high-quality publications were published in 2013 and some major trials studies were started. In Guillain-Barré syndrome, events included the launch of IGOS and a better understanding of diagnostic limits, the effect of influenza vaccination, and better care, but uncertainty remains about analgesics. A new mouse model was also described. In chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), diagnostic pitfalls can be recalled. Our knowledge of underlying pathophysiological processes has improved, and the value of monitoring with function and deficit scores has been demonstrated. IVIG can sometimes be effective longer than expected, but CIDP remains sensitive to corticosteroids, particularly with the long-term beneficial effects of megadose dexamethasone. The impact of fingolimod remains to be demonstrated in an ongoing trial. Advances concerning multifocal motor neuropathy, inflammatory plexopathy, and neuropathy with anti -MAG activity are discussed but treatments already recognized as effective should not be changed. Imaging of peripheral nerve progresses.

Treatment recommendations for patients with Waldenström macroglobulinemia (WM) and related disorders: IWWM-7 consensus

Waldenström macroglobulinemia (WM) is a distinct B-cell lymphoproliferative disorder for which clearly defined criteria for the diagnosis, initiation of therapy, and treatment strategy have been proposed as part of the consensus panels of International Workshops on WM (IWWM). As part of the IWWM-7 and based on recently published and ongoing clinical trials, the panels updated treatment recommendations. Therapeutic strategy in WM should be based on individual patient and disease characteristics (age, comorbidities, need for rapid disease control, candidacy for autologous transplantation, cytopenias, IgM-related complications, hyperviscosity, and neuropathy). Mature data show that rituximab combinations with cyclophosphamide/dexamethasone, bendamustine, or bortezomib/dexamethasone provided durable responses and are indicated for most patients. New monoclonal antibodies (ofatumumab), second-generation proteasome inhibitors (carfilzomib), mammalian target of rapamycin inhibitors, and Bruton's tyrosine kinase inhibitors are promising and may expand future treatment options. A different regimen is typically recommended for relapsed or refractory disease. In selected patients with relapsed disease after long-lasting remission, reuse of a prior effective regimen may be appropriate. Autologous stem cell transplantation may be considered in young patients with chemosensitive disease and in newly diagnosed patients with very-high-risk features. Active enrollment of patients with WM in clinical trials is encouraged.

Diagnosis and treatment of chronic acquired demyelinating polyneuropathies

Chronic neuropathies are operationally classified as primarily demyelinating or axonal, on the basis of electrodiagnostic or pathological criteria. Demyelinating neuropathies are further classified as hereditary or acquired-this distinction is important, because the acquired neuropathies are immune-mediated and, thus, amenable to treatment. The acquired chronic demyelinating neuropathies include chronic inflammatory demyelinating polyneuropathy (CIDP), neuropathy associated with monoclonal IgM antibodies to myelin-associated glycoprotein (MAG; anti-MAG neuropathy), multifocal motor neuropathy (MMN), and POEMS syndrome. They have characteristic--though overlapping--clinical presentations, are mediated by distinct immune mechanisms, and respond to different therapies. CIDP is the default diagnosis if the neuropathy is demyelinating and no other cause is found. Anti-MAG neuropathy is diagnosed on the basis of the presence of anti-MAG antibodies, MMN is characterized by multifocal weakness and motor conduction blocks, and POEMS syndrome is associated with IgG or IgA λ-type monoclonal gammopathy and osteosclerotic myeloma. The correct diagnosis, however, can be difficult to make in patients with atypical or overlapping presentations, or nondefinitive laboratory studies. First-line treatments include intravenous immunoglobulin (IVIg), corticosteroids or plasmapheresis for CIDP; IVIg for MMN; rituximab for anti-MAG neuropathy; and irradiation or chemotherapy for POEMS syndrome. A correct diagnosis is required for choosing the appropriate treatment, with the aim of preventing progressive neuropathy.

Current and future therapeutic approach for Waldenström's macroglobulinemia

Waldenström's macroglobulinemia is a rare B-cell malignancy defined by medullar infiltration by clonal lymphoplasmocytic cells and monoclonal IgM secretion. Treatment is reserved for symptomatic patients. The main first-line treatment strategies combine immunotherapy (principally the anti-CD20 monoclonal antibody rituximab) with chemotherapeutic agents, including alkylating agents, purine analogs and/or bortezomib. The overall response rate to these conventional treatments is between 70 and 90%, but a cure cannot be expected. For patients with relapsed or refractory disease, drugs that were not used for first-line treatment and other agents such as immunomodulators can be tried, but the response rate is generally lower and the responses are shorter lived. Recently, advances in our understanding of the biology of Waldenström's macroglobulinemia have led to the development of new drugs targeting hyperactive pathways. This review focuses on current treatment options and on new therapeutic developments.