Occlusive microangiopathy by immunoglobulin (IgM-kappa) precipitation: pathogenetic relevance in paraneoplastic cryoglobulinemic neuropathy

Paraneoplastic Neuropathies: What's New Since the 2004 Recommended Diagnostic Criteria

The diagnostic criteria published by the PNS (Paraneoplastic Neurological Syndromes) Euronetwork in 2004 provided a useful classification of PNS, including paraneoplastic neuropathies. Subacute sensory neuronopathy (SSN) was the most frequently observed peripheral PNS, whereas other forms of neuropathy, as sensory polyneuropathy, sensorimotor polyneuropathy, demyelinating neuropathies, autonomic neuropathies, and focal nerve or plexus lesions, were less frequent. At the time of publication, the main focus was on onconeural antibodies, but knowledge regarding the mechanisms has since expanded. The antibodies associated with PNS are commonly classified as onconeural (intracellular) and neuronal surface antibodies (NSAbs). Since 2004, the number of antibodies and the associated tumors has increased. Knowledge has grown on the mechanisms underlying the neuropathies observed in lymphoma, paraproteinemia, and multiple myeloma. Moreover, other unrevealed mechanisms underpin sensorimotor neuropathies and late-stage neuropathies, where patients in advanced stages of cancer—often associated with weight loss—experience some mild sensorimotor neuropathy, without concomitant use of neurotoxic drugs. The spectrum of paraneoplastic neuropathies has increased to encompass motor neuropathies, small fiber neuropathies, and autonomic and nerve hyperexcitability syndromes. In addition, also focal neuropathies, as cranial nerves, plexopathies, and mononeuropathies, are considered in some cases to be of paraneoplastic origin. A key differential diagnosis for paraneoplastic neuropathy, during the course of cancer disease (the rare occurrence of a PNS), is chemotherapy-induced peripheral neuropathy (CIPN). Today, novel complications that also involve the peripheral nervous system are emerging from novel anti-cancer therapies, as targeted and immune checkpoint inhibitor (ICH) treatment. Therapeutic options are categorized into causal and symptomatic. Causal treatments anecdotally mention tumor removal. Immunomodulation is sometimes performed for immune-mediated conditions but is still far from constituting evidence. Symptomatic treatment must always be considered, consisting of both drug therapy (e.g., pain) and attempts to treat disability and neuropathic pain.

Paraproteinemic neuropathies

The occurrence of a peripheral neuropathy (PN) in association with a monoclonal gammopathy is quite common and suggests that monoclonal proteins may play a pathogenetic role in peripheral nervous system damage. In fact, paraproteinemic PN constitute an heterogeneous group of disorders related to various pathogenetic factors, and the histopathologic features in peripheral nerve biopsies differ from one condition to another. In several well defined disorders, the responsibility of the monoclonal component in the development of the PN has been evidenced. This is the case for most of the PN associated with an IgM monoclonal gammopathy, either a monoclonal gammopathy of undetermined significance (MGUS) or Waldenstrom's macroglobulinemia. The responsibility of the monoclonal protein in the occurrence of amyloid neuropathy related to multiple myeloma is also recognized. However, most IgG or IgA MGUS, as well as the monoclonal component in POEMS syndrome, have an uncertain causal relationship with the neuropathy. PN associated with monoclonal cryoglobulin (type 1) are occasional and differ from those associated with mixed cryoglobulins (types 2 or 3).

Microvasculitic paraproteinaemic polyneuropathy and B-cell lymphoma

Microvasculitis may play a greater part in the pathogenesis of paraproteinaemic neuropathies than is generally recognised, producing tissue destruction by convergent immune and physical mechanisms. We present a patient with a clinical syndrome of mononeuritis multiplex and a circulating IgM lambda paraprotein, in whom bone marrow aspiration revealed a lymphoplasmacytoid lymphoma. Microvasculitic changes were present in the first nerve biopsy, and the second showed extensive destruction of neural architecture and deposition of IgM-related material. A 2-stage pathogenic cascade is postulated and explored with a review of the relevant literature.

Vasculitis and lymphoproliferative diseases

Vasculitis as a complication of lymphoproliferative diseases is relatively uncommon. Cutaneous vasculitis is most commonly necrotizing and leukocytoclastic. Granulomatous vasculitis occurs rarely with lymphoproliferative diseases, and even less commonly T-cell lymphocytic vasculitis with eosinophilia. The most common systemic vasculitis is caused by cryoglobulinemia, due to either lymphocytic lymphoma or Waldenström's macroglobulinemia. Other unusual associations involving systemic vasculitides include polyarteritis nodosa and hairy cell leukemia, Wegener's granulomatosis and Hodgkin's disease, granulomatous angiitis of the central nervous system and lymphoma, temporal arteritis and lymphoma, and Henoch-Schönlein purpura and lymphoma. The vasculitis may predate the diagnosis of the lymphoproliferative disease, and patients with vasculitis should be screened and monitored for lymphoproliferative diseases.

Immunocytochemical localization of immunoglobulins in disc herniations

STUDY DESIGN

Disc herniation and control discs were studied for the presence of immunoglobulins immunocytochemically.

OBJECTIVES

To study a possible presence of immunoglobulin complexes in herniated disc tissue and to locate them at the tissue level by immunocytochemistry; to compare immunohistologic findings with those obtained in control disc tissue; and to compare the prevalences of immunoglobulin M and immunoglobulin G.

SUMMARY OF BACKGROUND DATA

In herniated disc tissue, high activity of inflammatory phospholipase A2 was previously demonstrated, and inflammatory cells were noted immunohistochemically. Immunoglobulins G and M were observed biochemically but have not been located at the tissue level.

METHODS

Fifty-two disc herniations and three macroscopically normal fresh cadaver discs were managed by an identical immunocytochemical protocol, using monoclonal antihuman antibodies to immunoglobulins M and G.

RESULTS

In 29 of 52 disc herniations (56%), immunoglobulin M deposits were observed, and in 18 of 52 disc herniations (35%) immunoglobulin G could be demonstrated. Almost all the disc herniations where immunoglobulin G was present also contained immunoglobulin M deposits (except for two). In the control discs studied, neither immunoglobulin could be observed immunohistochemically. The immunoglobulin deposits were noted in areas where blood vessels were also present. Morphologically, immunoglobulin immunoreactivity resembling immune complexes was observed.

CONCLUSIONS

The results lend support to previous suggestions of inflammation and immune reaction in disc herniations, including previous biochemical studies suggesting immunoglobulin deposition. The exact role of the demonstrated immunoglobulins in disc tissue pathophysiology will have to be clarified further.

Osteosclerotic myeloma and 'POEMS' syndrome

Metabolic bone disease is a major cause of morbidity and mortality in patients suffering from multiple myeloma. This usually results from an imbalance between the osteoclast and osteoblast activity of bone resorption and formation due to the secretion of an osteoclast-activating factor by the myeloma cells. This generally takes the form of lytic lesions, hypercalcaemia and osteoporosis but, in a minority of patients, osteosclerosis is a striking feature. In a proportion of patients with gammopathy and the osteosclerotic form of the disease, there appears to be an association with other symptom complexes including Polyneuropathy, organomegaly, endocrine changes, and skin abnormalities. This article summarizes the clinical, radiological and laboratory features of this syndrome, which is known by the acronym 'POEMS'. It is important to recognize this condition, as it carries a better prognosis than the more common lytic form of the disease and because vincristine, and agents frequently used to treat this condition, may severely exacerbate the neuropathy and should be avoided. This syndrome is also important because it may give some insight into the pathophysiology of the plasma-cell dyscrasias.

Lymphoma, paraproteinaemia, and neuropathy

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Effects of Lymphoma on the Peripheral Nervous System

Peripheral nervous system abnormalities occur in 5% of patients with lymphoma and have a wide differential diagnosis. Herpes zoster is the commonest cause. Vinca alkaloids are the only drugs used in lymphoma which commonly cause neuropathy. Compression or infiltration of nerve roots by lymphoma is a rare presenting feature but becomes more common with advanced disease. Radiation plexopathy does not usually develop until at least 6 months after irradiation and can be difficult to distinguish from neoplastic infiltration. Either multifocal infiltration of nerves or lymphoma-associated vasculitis may present as a peripheral neuropathy. The incidence of Guillain-Barré (GBS) syndrome, and possibly chronic idiopathic demyelinating polyradiculoneuropathy, appears to be increased in association with lymphoma, especially Hodgkin's disease. Subacute sensory neuronopathy and subacute lower motor neuronopathy have both been reported as paraneoplastic syndromes associated with Hodgkin's disease. Treatment of the underlying lymphoma is only rarely followed by recovery of the associated neuropathy.