Peripheral neuropathy in IgM monoclonal gammopathy and Wäldenstrom's macroglobulinemia: a frequent complication in elderly males with low MAG-reactive serum monoclonal component

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.

Demyelinating polyneuropathy and lymphoplasmacytic lymphoma coexisting in 36-year-old man: A case report

BACKGROUND

Lymphoplasmacytic lymphoma is a rare non-Hodgkin’s lymphoma, occurring mostly in the elderly. It develops slowly and leads to malignant proliferation of lymphoid line cells in the bone marrow, lymph nodes and spleen. It may also affect nerve roots and meninges; some patients develop sensorimotor polyneuropathy which may precede general symptoms of lymphoma.

CASE SUMMARY

We present a case of a 36-year-old man diagnosed in 2012 with chronic inflammatory demyelinating polyneuropathy (CIDP), then he was hospitalized in 2019 due to progressive symptoms of heart failure and significant weight loss over the previous four months. Based on clinical and laboratory findings a diagnosis of lymphoplasmacytic lymphoma was suspected and confirmed by bone marrow flow cytometry. There was no improvement in the results of laboratory tests and the patient's condition after immediate implementation of chemotherapy. Patient died on the fifth day of treatment.

CONCLUSION

While CIDP and malignant disease co-occurrence is rare, it should be suspected and investigated in patients with atypical neuropathy symptoms.

Waldenstrom's macroglobulinemia in the era of immunotherapy

Waldenstrom macroglobulinemia (WM) is a lymphoplasmacytic lymphoma that presents with symptomatic anemia, thrombocytopenia, constitutional symptoms, extramedullary disease and rarely hyperviscosity syndrome. The presence of both IgM monoclonal protein and ≥10% monoclonal lymphoplasmacytic cells is required for the diagnosis. MyD88 is present in 67-90% of patients but is not pathognomonic for WM. Many patients who fulfill the criteria of WM are asymptomatic and do not require treatment. Recent advances in the understanding of the biology of WM have paved the way for new treatment options. The use of novel agents with or without rituximab enables the use of effective chemotherapy-free regiments upfront and in the relapsed setting. New targeted treatments such as venetoclax and CXCR4 antagonists are being investigated.

Waldenstrom-associated anti-MAG paraprotein polyneuropathy with neurogenic tremor

A 71-year-old female patient presented with a 14-year history of slowly progressive distal limb numbness, paraesthesia and reduced vibration perception, ataxic gait and intentional tremor. Examination revealed with a length-dependent sensory neuropathy. Nerve conduction studies showed a chronic sensorimotor inflammatory demyelinating polyneuropathy. Intravenous immunoglobulin treatment (on two occasions) proved ineffective. Serum electrophoresis showed increased monoclonal IgM with kappa light chains. Anti-myelin-associated glycoprotein (MAG) levels were extremely elevated, >70 000 BTU. Bone marrow biopsy revealed 15%-20% small B cells and positive MYD88 mutation, indicative of Waldenstrom macroglobulinaemia. A diagnosis of Waldenstrom-associated anti-MAG paraprotein neuropathy with intentional (neurogenic) tremor was made. Repeat nerve conduction study showed a severe sensory demyelinating neuropathy with no axonal lesion. Treatment with rituximab was given for 1 month with minimal improvement. Repeat anti-MAG levels dropped to 53 670 BTU, with minimal clinical improvement.

Patient With 2 Hematologic Malignancies Presenting as Neurolymphomatosis

Peripheral nervous system damage from hematologic malignancies is related to neoplastic cells infiltration of peripheral nerves or to monoclonal antibody production cross-reacting with peripheral nerves' antigens. Neurolymphomatosis (NL), a rare manifestation of hematologic malignancies, occurs when malignant cells invade the peripheral nerves leading to various manifestations. Here, we report a case of NL with 2 hematologic malignancies in a 79-year-old woman presenting with lower extremity pain/weakness. Investigation revealed anemia, IgM kappa monoclonal gammopathy, and elevated anti-MAG titer. Electrodiagnostic studies were consistent with mononeuropathy multiplex while imaging suggested malignancy in her ovaries and right S1 nerve root. Bone marrow and ovarian biopsies revealed chronic myelomonocytic leukemia, Waldenstrom macroglobulinemia, and diffuse large B-cell lymphoma. She received standard chemotherapy resulting in radiographic resolution of disease and symptomatic relief. NL can precede the diagnosis of hematologic malignancy but its symptoms are not easily identifiable, whereas management depends on the treatment of the underlying tumor.

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.

The Neuropathies of Waldenström's Macroglobulinemia (WM) and IgM-MGUS

Background:

Neuropathy is common in Waldenström's macroglobulinemia (WM, an IgM-associated lymphoplasmacytic lymphoma) and in IgM-monoclonal gammopathy of undetermined significance (IgM-MGUS). Paraneoplastic or paraimmune mechanisms are thought to be involved in the pathogenesis of these neuropathies. Attempts at distinguishing WM and IgM-MGUS neuropathies are lacking especially among bone marrow (BM) confirmed patients.

Methods:

Retrospective analyses were performed on BM confirmed WM (N=30) and IgM-MGUS (N=73) neuropathy patients with neurologic assessments and hematologic features.

Results:

The presence of anemia and quantity of IgM monoclonal protein were significantly greater in WM. Based on multiple neurologic assessments differences were not found for: 1) length of time from neurologic symptom onset to evaluation; 2) chief complaint of painless loss of feeling in the feet, Romberg's sign and tremor; and 3) clinical motor, sensory and reflex abnormalities. Autonomic testing was normal in both diseases. Using nerve conduction (NCS) criteria for demyelination, 62% of IgM-MGUS and 27% of WM met this criteria (p=0.013). IgM MGUS patients had greater terminal conduction slowing by ulnar residual latency calculation (<0.01). The degree of axonal loss as measured by summated compound muscle action potentials and available nerve biopsy was not significantly different between diseases.

Conclusion:

Although WM and IgM-MGUS must be distinguished for hematologic prognosis and treatment, clinical neuropathy presentations of WM and IgM-MGUS are similar and likely related to comparable axonal loss in both conditions. Despite these similarities, evidence of demyelination was found by electrophysiologic studies much more commonly in IgM-MGUS. This difference may reflect varied immune mechanism(s) in the two disorders.

Clinical assessment of the sensory ataxias; diagnostic algorithm with illustrative cases

Ataxia is a common neurological syndrome resulting from cerebellar, vestibular or sensory disorders. The recognition and characterisation of sensory ataxia remains a challenge. Cerebellar ataxia is the more common and easier to identify; sensory ataxia is often mistaken for cerebellar ataxia, leading to diagnostic errors and delays. A coherent aetiological work-up is only possible if clinicians initially recognise sensory ataxia. We discuss ways to separate sensory from cerebellar ataxia, the causes of sensory ataxia and the clinico-neurophysiological syndromes causing the sensory ataxia syndromes. We summarise a logical tiered approach as a diagnostic algorithm.

Unique association of Waldenström macroglobulinemia with optic neuritis and monoclonal T cell expansion

Waldenström macroglobulinemia is a lymphoplasmacytic lymphoma characterized by production of the immunoglobulin M (IgM) monoclonal protein. Commonly involved sites are the bone marrow, lymph nodes, and spleen. Lymphoplasmacytic infiltration of the central nervous system (CNS), in contrast, is referred to as Bing-Neel syndrome, and is an extremely rare phenomenon. Here, we present a unique case of Waldenström macroglobulinemia with optic neuritis accompanied by monoclonal expansion of T cells, which recovered after administration of CNS-targeting chemotherapy. Although the underlying causal relationships in this case remain obscure, aberrantly expanded T cells may have contributed to the development of optic neuritis, and we should be reminded that some types of cranial neuropathy in Waldenström macroglobulinemia may be reversible.

Neuropathy and monoclonal gammopathy

The association of neuropathy with monoclonal gammopathy has been known for several years, even if the clinical and pathogenetic relevance of this association is not completely defined. This is not a marginal problem since monoclonal gammopathy is present in 1-3% of the population above 50 years in whom it is often asymptomatic, and in at least 8% of patients is associated with a symptomatic neuropathy, representing one of the leading causes of neuropathy in aged people. Monoclonal gammopathy may result from malignant lymphoproliferative diseases including multiple myeloma or solitary plasmocytoma, Waldenström's macroglobulinemia (WM), other IgM-secreting lymphoma or chronic lymphocytic leukemia, and primary systemic amyloidosis (AL). In most instances it is not associated with any of these disorders and is defined monoclonal gammopathy of undetermined significance (MGUS) for its possible, though infrequent, evolution into malignant forms. Several data support the pathogenetic role of the monoclonal gammopathy in the neuropathy particularly when of IgM isotype where IgM reactivity to several neural antigens has been reported. Increased levels of VEGF have been implicated in POEMS syndrome. However, there are as yet no defined therapies for these neuropathies, as their efficacy has not been confirmed in randomized trials.

Heterogeneous spectrum of neuropathies in Waldenström's macroglobulinemia: a diagnostic strategy to optimize their management

Neuropathy in Waldenström's macroglobulinemia (WM) is very heterogeneous. We retrospectively studied 40 patients with WM and neuropathy to analyze the different presentations and mechanisms encountered and to propose a diagnostic strategy. Twenty-five patients (62.5%) had axonal neuropathy, related to the following mechanisms: amyloid neuropathy (n = 5), cryoglobulinemic neuropathy (n = 5), neuropathy associated with tumoral infiltration (n = 2), vasculitic neuropathy (n = 2), a clinical motor neuropathy possibly of dysimmune origin (n = 6), or an unclassified mechanism (n = 5). A demyelinating pattern was observed in 15 patients, 10 having anti-myelin-associated glycoprotein (anti-MAG) antibodies and 5 having neuropathy related to chronic inflammatory demyelinating polyradiculoneuropathy. On the basis of these results, we propose a diagnostic strategy combining: (1) an EMG to distinguish between a demyelinating and an axonal pattern; (2) measurement of anti-MAG and anti-ganglioside antibodies; (3) screening for "red flag" features to orientate further investigations. This strategy may help clinicians to identify the mechanism of neuropathy in order to adapt the therapeutic strategy.

Disease associations with monoclonal gammopathy of undetermined significance: a population-based study of 17,398 patients

OBJECTIVE

To systematically study the association of monoclonal gammopathy of undetermined significance (MGUS) with all diseases in a population-based cohort of 17,398 patients, all of whom were uniformly tested for the presence or absence of MGUS.

PATIENTS AND METHODS

Serum samples were obtained from 77% (21,463) of the 28,038 enumerated residents in Olmsted County, Minnesota. Informed consent was obtained from patients to study 17,398 samples. Among 17,398 samples tested, 605 cases of MGUS and 16,793 negative controls were identified. The computerized Mayo Medical Index was used to obtain information on all diagnoses entered between January 1, 1975, and May 31, 2006, for a total of 422,663 person-years of observations. To identify and confirm previously reported associations, these diagnostic codes were analyzed using stratified Poisson regression, adjusting for age, sex, and total person-years of observation.

RESULTS

We confirmed a significant association in 14 (19%) of 75 previously reported disease associations with MGUS, including vertebral and hip fractures and osteoporosis. Systematic analysis of all 16,062 diagnostic disease codes found additional previously unreported associations, including mycobacterium infection and superficial thrombophlebitis.

CONCLUSION

These results have major implications both for confirmed associations and for 61 diseases in which the association with MGUS is likely coincidental.

Disease associations with monoclonal gammopathy of undetermined significance: a population-based study of 17,398 patients

OBJECTIVE

To systematically study the association of monoclonal gammopathy of undetermined significance (MGUS) with all diseases in a population-based cohort of 17,398 patients, all of whom were uniformly tested for the presence or absence of MGUS.

PATIENTS AND METHODS

Serum samples were obtained from 77% (21,463) of the 28,038 enumerated residents in Olmsted County, Minnesota. Informed consent was obtained from patients to study 17,398 samples. Among 17,398 samples tested, 605 cases of MGUS and 16,793 negative controls were identified. The computerized Mayo Medical Index was used to obtain information on all diagnoses entered between January 1, 1975, and May 31, 2006, for a total of 422,663 person-years of observations. To identify and confirm previously reported associations, these diagnostic codes were analyzed using stratified Poisson regression, adjusting for age, sex, and total person-years of observation.

RESULTS

We confirmed a significant association in 14 (19%) of 75 previously reported disease associations with MGUS, including vertebral and hip fractures and osteoporosis. Systematic analysis of all 16,062 diagnostic disease codes found additional previously unreported associations, including mycobacterium infection and superficial thrombophlebitis.

CONCLUSION

These results have major implications both for confirmed associations and for 61 diseases in which the association with MGUS is likely coincidental.

Waldenström macroglobulinemia

In the past 36 months, new developments have occurred both in the understanding of the biology of Waldenström macroglobulinemia (WM) and in therapeutic options for WM. Here, we review the classification, clinical features, and diagnostic criteria of the disease. WM is a B-cell neoplasm characterized by lymphoplasmacytic infiltration of the bone marrow and a monoclonal immunoglobulin M (IgM) protein. The symptoms of WM are attributable to the extent of tumor infiltration and to elevated IgM levels. The most common symptom is fatigue attributable to anemia. The prognostic factors predictive of survival include the patient's age, β2-microglobulin level, monoclonal protein level, hemoglobin concentration, and platelet count. Therapy is postponed for asymptomatic patients, and progressive anemia is the most common indication for initiation of treatment. The main therapeutic options include alkylating agents, nucleoside analogues, and rituximab. Studies involving combination chemotherapy are ongoing, and preliminary results are encouraging. No specific agent or regimen has been shown to be superior to another for treatment of WM. Novel agents such as bortezomib, perifosine, atacicept, oblimersen sodium, and tositumomab show promise as rational targeted therapy for WM.

Hairy cell leukaemia complicated by anti-MAG paraproteinemic demyelinating neuropathy: resolution of neurological syndrome after cladribrine treatment

Hairy cell leukaemia (HCL) occasionally displays a monoclonal gammopathy, yet the association of HCL with paraproteinemic demyelinating neuropathy (PDN) has not been reported. We describe a HCL case complicated by PDN and high titers of monoclonal IgM against myelin associated glycoprotein (MAG). Heavy and light chains of the patient's anti-MAG monoclonal protein were consistent with those expressed by HCL cells. After treatment with cladribrine, remission of HCL strictly paralleled disappearance of the IgM monoclonal protein and of the serum anti-MAG activity, and led to PDN clinical and electrophysiological improvement. Purine analogs may represent a choice in IgM PDN associated with lymphoproliferative disorders.

Peripheral nervous system involvement in patients with cancer

Involvement of the peripheral nervous system (PNS) is common in patients with cancer and any part, including motor neurons, sensory ganglia, nerve roots, plexuses, cranial and peripheral nerves, and neuromuscular junctions, can be affected. Different mechanisms can initiate damage associated with cancer-related PNS disorders. These include tumour infiltration, toxicity of treatments, metabolic and nutritional perturbations, cachexia, virus infections, and paraneoplastic neurological syndromes. The type of cancer, lymphoma, or solid tumour is a further determinant of a PNS disorder. In this Review we discuss the different causes and mechanisms of disorders of the PNS in patients with cancer and we will focus on their assessment and diagnosis.

Dixièmes Journées des Maladies du Système Nerveux Périphérique Neuropathies associées aux lymphomas

Peripheral neurological complications of lymphomas are rare, but all types of neuropathy can be observed in the context of lymphoma. This great clinical heterogeneity can be related to the variety of pathological processes that can affect the peripheral nerve or be linked to the different subtypes of lymphoma. In addition to the common causes of peripheral nerve involvement, such as iatrogenic toxicity, there are mechanisms that are more specifically related to lymphomas, such as nerve tumor infiltration, or dysimmune perturbations induced by the hemopathy. These dysimmune processes can result in various neuropathies, such as inflammatory demyelinating polyradiculoneuropathy, or neuropathies secondary to the secretion of a monoclonal immunoglobulin. Identifying the mechanism of the neuropathy is necessary in order to determine the therapeutic options and to improve the prognosis.

European Federation of Neurological Societies/Peripheral Nerve Society guideline on management of paraproteinaemic demyelinating neuropathies: report of a joint task force of the European Federation of Neurological Societies and the Peripheral Nerve Society*

BACKGROUND

Paraprotein-associated neuropathies have heterogeneous clinical, neurophysiological, neuropathological and haematological features. Objectives. To prepare evidence-based and consensus guidelines on the clinical management of patients with both a demyelinating neuropathy and a paraprotein (paraproteinaemic demyelinating neuropathy, PDN).

METHODS

Search of MEDLINE and the Cochrane library, review of evidence and consensus agreement of an expert panel.

RECOMMENDATIONS

In the absence of adequate data, evidence based recommendations were not possible but the panel agreed the following good practice points: (1) Patients with PDN should be investigated for a malignant plasma cell dyscrasia. (2) The paraprotein is more likely to be causing the neuropathy if the paraprotein is immunoglobulin (Ig)M, antibodies are present in serum or on biopsy, or the clinical phenotype is chronic distal sensory neuropathy. (3) Patients with IgM PDN usually have predominantly distal and sensory impairment, with prolonged distal motor latencies, and often anti-myelin associated glycoprotein antibodies. (4) IgM PDN sometimes responds to immune therapies. Their potential benefit should be balanced against their possible side-effects and the usually slow disease progression. (5) IgG and IgA PDN may be indistinguishable from chronic inflammatory demyelinating polyradiculoneuropathy, clinically, electrophysiologically, and in response to treatment. (6) For POEMS syndrome, local irradiation or resection of an isolated plasmacytoma, or melphalan with or without corticosteroids, should be considered, with haemato-oncology advice.

European Federation of Neurological Societies/Peripheral Nerve Society Guideline* on management of paraproteinemic demyelinating neuropathies. Report of a joint task force of the European Federation of Neurological Societies and the Peripheral Nerve Society

BACKGROUND

Paraprotein-associated neuropathies have heterogeneous clinical, neurophysiological, neuropathological, and hematological features.

OBJECTIVES

The aim of this guideline was to prepare evidence-based and consensus guidelines on the clinical management of patients with both a demyelinating neuropathy and a paraprotein [paraproteinemic demyelinating neuropathy (PDN)].

METHODS

Disease experts and a representative of patients considered references retrieved from MEDLINE and the Cochrane Library and prepared statements that were agreed in an iterative fashion.

RECOMMENDATIONS

In the absence of adequate data, evidence-based recommendations were not possible, but the Task Force agreed on the following good practice points: (1) patients with PDN should be investigated for a malignant plasma cell dyscrasia; (2) the paraprotein is more likely to be causing the neuropathy if the paraprotein is immunoglobulin M (IgM), antibodies are present in serum or on biopsy, or the clinical phenotype is chronic distal sensory neuropathy; (3) patients with IgM PDN usually have predominantly distal and sensory impairment, with prolonged distal motor latencies, and often anti-myelin-associated glycoprotein antibodies; (4) IgM PDN sometimes responds to immunotherapies. Their potential benefit should be balanced against their possible side effects and the usually slow disease progression; (5) IgG and IgA PDN may be indistinguishable from chronic inflammatory demyelinating polyradiculoneuropathy clinically, electrophysiologically, and in response to treatment; and (6) for POEMS syndrome, local irradiation or resection of an isolated plasmacytoma, or melphalan with or without corticosteroids, should be considered, with hemato-oncology advice.

Peripheral neuropathies in Waldenström's macroglobulinaemia

OBJECTIVE

We sought to determine the prevalence, clinical features, and laboratory characteristics of polyneuropathies in Waldenström's macroglobulinaemia (WM), a malignant bone marrow disorder with lymphocytes that produce monoclonal IgM.

METHODS

We prospectively studied 119 patients with WM and 58 controls. Medical history was taken, and neurological examinations, electrodiagnostic tests, and serum studies were performed by different examiners who were blinded to results except the diagnosis of WM.

RESULTS

Polyneuropathy symptoms, including discomfort and sensory loss in the legs, occurred more frequently (p<0.001) in patients with WM (47%) than in controls (9%). Patients with WM had 35% lower quantitative vibration scores, and more frequent pin loss (3.4 times) and gait disorders (5.5 times) than controls (all p<0.001). Patients with IgM binding to sulphatide (5% of WM) had sensory axon loss; those with IgM binding to myelin associated glycoprotein (MAG) (4% of WM) had sensorimotor axon loss and demyelination. Patients with WM with IgM binding to sulphatide (p<0.005) or MAG (p<0.001) had more severe sensory axon loss than other patients with WM. Demyelination occurred in 4% of patients with WM with no IgM binding to MAG. Age related reductions in vibration sense and sural SNAP amplitudes were similar ( approximately 30%) in WM and controls.

CONCLUSIONS

Peripheral nerve symptoms and signs occur more frequently in patients with WM than controls, involve sensory modalities, and are often associated with gait disorders. IgM binding to MAG or sulphatide is associated with a further increase in the frequency and severity of peripheral nerve involvement. Age related changes, similar to those in controls, add to the degree of reduced nerve function in patients with WM.

Neurological aspects of multiple myeloma and related disorders

The spectrum of neurologic complications of multiple myeloma (MM) and related conditions is as diverse as the conditions themselves. Complications range from direct compression (radiculopathy, spinal cord compression, base-of-the-skull tumor) to the infiltrative (amyloid, peripheral neuropathies, and numb chin syndrome of myeloma), the metabolic (slowed mentation from hyperviscosity, hypercalcemia, or uremia), and to autoimmune or cytokine-mediated (peripheral neuropathy). The two most common presentations are the compressive radiculopathy one sees in multiple myeloma and the peripheral neuropathies associated with many of the other disorders. The authors will review the neurologic complications of MM, monoclonal gammopathy of undetermined significance (MGUS), Waldenström macroglobulinemia (WM), POEMS syndrome, amyloidosis, and cryoglobulinemia.

Monoclonal gammopathies of undetermined significance: a review

Monoclonal gammopathy of undetermined significance (MGUS) denotes the presence of a monoclonal protein (M-protein) in patients without evidence of multiple myeloma (MM), macroglobulinemia, amyloidosis (AL), or a related plasma cell proliferative disorder. MGUS is found in approximately 3% of persons older than 70 years and in about 1% of those older than 50 years. In a series of 1384 patients from south-eastern Minnesota in whom MGUS was diagnosed at Mayo Clinic from 1960 through 1994, the risk of progression was 1% per year. Patients were at risk of progression even after 25 years or more of a stable monoclonal gammopathy. The risk of development of MM was increased by 25-fold, the risk of macroglobulinemia was 46-fold, and the risk of primary AL was 8.4-fold when compared with a similar population (Surveillance, Epidemiology and End Results). The concentration of the serum M-protein was the major independent predictor of progression. Patients with an immunoglobulin M (IgM) or an IgA monoclonal gammopathy had a higher risk of progression than those with an IgG monoclonal gammopathy. The presence of a urine M-protein or the reduction of one or more uninvolved Igs was not a risk factor for progression. MGUS may be associated with many different disorders, including lymphoproliferative diseases, leukemia, connective tissue disorders, dermatologic diseases, and neurologic disorders.

Monoclonal gammopathies of undetermined significance

The term 'monoclonal gammopathy of undetermined significance' denotes the presence of a monoclonal protein in patients without evidence of multiple myeloma, macroglobulinemia, amyloidosis or related plasma cell proliferative disorders. The disorder has been found in approximately 3% of persons older than 70 years and in approximately 1% of persons older than 50 years. A population-based study included 1384 patients from south-eastern Minnesota who had the disorder diagnosed at the Mayo Clinic from 1960 through 1994. Risk of progression was about 1% per year, but patients were at risk of progression even after 25 years or more of stable monoclonal gammopathy of undetermined significance. The risk for development of multiple myeloma was increased 25-fold; the risk of macroglobulinemia, 46-fold; and the risk of primary amyloidosis, 8.4-fold. Concentration and type of monoclonal protein were the only independent predictors of progression. The presence of a urine monoclonal protein and the reduction of one or more uninvolved immunoglobulins were not risk factors for progression. Monoclonal gammopathy of undetermined significance may be associated with various disorders, including lymphoproliferative diseases, leukemia, von Willebrand disease, connective tissue diseases and neurologic disorders.

Anti-myelin-associated glycoprotein antibodies predict the development of neuropathy in asymptomatic patients with IgM monoclonal gammopathy

We examined 52 asymptomatic patients with IgM monoclonal gammopathy and correlated anti-myelin-associated glycoprotein (anti-MAG) IgM with the presence of subclinical neuropathy and, in 24 of these patients, with the development of symptomatic neuropathy during a follow-up interval of 40 to 144 months (mean, 75.3 months). Three of 6 patients (50%) with high (>1/6,400) anti-MAG IgM had subclinical neuropathy at entry compared with 2 of 46 patients (4.3%) with low or no reactivity. At follow-up, a symptomatic neuropathy occurred in 3 of 4 patients with high reactivity and in 3 of 21 patients with low or no reactivity. The correlation of high anti-MAG IgM with the presence of subclinical neuropathy or the development of symptomatic neuropathy supports its pathogenetic role in the neuropathy.

Autoimmunity and extranodal lymphocytic infiltrates in lymphoproliferative disorders

OBJECTIVE

To examine the relationship between autoimmunity and extranodal lymphocytic infiltrates in different lymphoproliferative disorders with immunoglobulin alterations.

SUBJECTS AND DESIGN

A clinical review combined with a retrospective cohort study of 380 patients, 28 with monoclonal gammopathy of undetermined significance, three with common variable immunodeficiency, 147 with chronic lymphocytic leukaemia, 57 with Waldenström's macroglobulinaemia and 145 with non-Hodgkin's malignant lymphoma.

SETTING

A university hospital and The State Serum Institute in Copenhagen.

INTERVENTION

Clinical examination of each patient with special attention to chronic inflammatory and autoimmune manifestations. Biopsies were taken from non-infectious infiltrates, some of which were additionally tested with PCR analysis for gene rearrangements. Serological screening with a test battery for various autoantibodies was used in combination with techniques for the detection of M-components and monoclonal B-cell proliferation.

MAIN OUTCOME MEASURES

Clinical and/or serological autoimmune manifestations, M-component and other immunoglobulin alterations, and inflammatory tissue changes were studied in patients with chronic inflammatory, polyclonal or oligoclonal pseudolymphomas and in monoclonal, malignant extranodal lymphomas.

RESULTS

In 380 consecutive patients, 49 (12.9%) had extranodal manifestations, of whom 47 also had autoimmune manifestations. Nearly half of the 47 patients had more than one autoimmune manifestation. There was a strong correlation between clinical signs and corresponding autoantibodies such as anti-SSA and -SSB antibodies in Sjögren's syndrome (10 cases), antithyroid peroxidase antibodies in thyroiditis and Graves' disease (10 cases), and parietal cell antibodies in gastric ulcers with maltoma (12 cases). Clinical and serological signs of autoimmunity correlated strongly with female sex (34, 72% women; and 13, 28% men) and with immunoglobulin alterations.

CONCLUSIONS

To our knowledge this is the first systematic review of B-lymphoproliferative and autoimmune disorders indicating that pseudolymphoma and malignant lymphomas, including maltomas, may develop in the context of a permanent autoantigenic drive.

[Polyneuropathies in monoclonal gammopathy of undetermined significance: initial manifestation of a lymphoma]

BACKGROUND

Monoclonal gammopathies-including so-called monoclonal gammopathies of undetermined significance-MGUS-may cause polyneuropathies, even if immunoglobulin concentrations are within a normal range.

CASE REPORT

We report on a patient with a rapidly progressive polyneuropathy with severe motor disturbances in whom a small amount of a monoclonal IgM kappa cryoglobulin was found. Only by extensive, repeatedly performed diagnostic procedures could scattered lymphoma cells be detected. Nonspecific immunosuppression had been unsuccessful but eventually a more specific chemotherapy led to an almost complete, sustained recovery.

CONCLUSION

This case shows that in patients with a polyneuropathy of uncertain etiology monoclonal immunoglobulins should be looked for and that a MGUS can precede a lymphoma. Therefore these, patients with a MGUS and clinical deterioration despite conventional immunosuppressive treatment should undergo large-scale diagnostic check-up to make sure that the chance for an adequate chemotherapy is taken.

Monoclonal gammopathy of undetermined significance (MGUS)

MGUS is characterized by a serum M-protein concentration of less than 30 milligrams (3 g/dl), fewer than 10% plasma cells in the bone marrow, no or only small amounts of M-protein (Bence Jones protein) in the urine, the absence of lytic lesions, anaemia, hypercalcaemia and renal insufficiency, and most importantly, stability of the M-protein and failure of the development of additional abnormalities. Electrophoresis on agarose, followed by immunoelectrophoresis or immunofixation for the identification of the type of M-protein, is recommended. In 1994, 971 patients at the Mayo Clinic were found with a serum M-protein. The most frequent diagnosis was MGUS, which occurred in 52% of patients. MGUS is found in approximately 3% of people older than 70 years and in at least 1% of those aged over 50. The incidence of monoclonal gammopathies increases with advancing age and is higher in African-Americans than in Caucasians. Two hundred and forty-one patients from the Mayo Clinic with a monoclonal gammopathy but no evidence of MM, macroglobulinaemia, amyloidosis, lymphoma or related disorders were followed for 24-38 years. In 62 patients (26%), multiple myeloma, macroglobulinaemia, amyloidosis or a malignant lymphoproliferative disorder developed (the actuarial rate of development of serious disease at 10 years was 16%; at 20 years, 33%; and at 25 years, 40%). Thirty patients (12%) were alive and had a stable M-protein value. In 23 patients (10%), the serum M-protein level increased to 30 milligrams (3 g/dl) or more, but they did not require therapy for myeloma or related disorders. Fifty-two per cent of patients (126) died of unrelated diseases without the development of a malignant plasma cell lymphoproliferative disorder. The actual rate of development of serious disease was the same for those with IgG, IgA and IgM M-proteins. Differentiation of MGUS from myeloma or macroglobulinaemia is difficult. The M-protein value must be measured periodically and clinical evaluation carried out to determine whether or not serious disease has developed.