Skin and Nerve Neovascularization in POEMS Syndrome: Insights From a Small Cohort

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.

Efficacy of novel agents in patients with nephropathy associated with POEMS syndrome

Objective

To evaluate the clinical characteristics and outcomes of patients with nephropathy associated with POEMS syndrome who received novel agents in combination with dexamethasone therapy, and renal pathological changes based on repeat biopsy in some patients after these novel-agent-based therapies.

Methods

The records of patients with nephropathy associated with POEMS syndrome in a single hospital from May 2017 to February 2021 were retrieved and studied in detail. All the patients received four cycles of initial novel-agent-based regimens such as bortezomib and dexamethasone (BD) or thalidomide plus dexamethasone (TD) or lenalidomide plus dexamethasone (RD) treatment. We further evaluated the pathological efficacy of these novel agents by repeat renal biopsy.

Results

Twelve patients with an average age of 48.6 ± 8.3 years diagnosed with nephropathy associated with POEMS syndrome were enrolled in this study. The duration from disease onset to renal biopsy was 28(8.3 ~ 54.5) months. All patients achieved good clinical responses in different degree after four cycles of initial novel agents in combination with dexamethasone therapy. After the treatment with novel-agent-based regimens, the levels of proteinuria decreased in most patients and were negative in five patients. The levels of serum creatinine (SCr) decreased in ten patients. Serum M protein was negative in four patients and still positive in the other eight patients. The levels of serum vascular endothelial growth factor (VEGF) were detected in seven patients, which were all decreased. The levels of interleukin-6 (IL-6) were detected in eight patients, which were also decreased. Repeat biopsies were performed after four cycles of novel-agent-based therapies in four patients who were all treated with BD treatment. Mesangiolysis, mesangial cells proliferation, endothelial cells proliferation, subendothelial space widening and acute renal tubulointerstitial lesions improved, the chronic renal tubulointerstitial lesions were stable.

Conclusions

Novel agents improved clinical manifestations in patients with nephropathy associated with POEMS syndrome. In addition, novel-agent-based regimens such as BD treatment improved renal pathological manifestations, which suggested that novel agents could improve renal prognosis of the patients from the perspective of renal pathology.

Immune mechanisms, the role of complement, and related therapies in autoimmune neuropathies

INTRODUCTION

Autoimmune neuropathies have diverse presentations and underlying immune mechanisms. Demonstration of efficacy of therapeutic agents that inhibit the complement cascade would confirm the role of complement activation.

AREAS COVERED

A review of the pathophysiology of the autoimmune neuropathies, to identify those that are likely to be complement mediated.

EXPERT OPINION

Complement mediated mechanisms are implicated in the acute and chronic neuropathies associated with IgG or IgM antibodies that target the Myelin Associated Glycoprotein (MAG) or gangliosides in the peripheral nerves. Antibody and complement mechanisms are also suspected in the Guillain-Barré syndrome and chronic inflammatory demyelinating neuropathy, given the therapeutic response to plasmapheresis or intravenous immunoglobulins, even in the absence of an identifiable target antigen. Complement is unlikely to play a role in paraneoplastic sensory neuropathy associated with antibodies to HU/ANNA-1 given its intracellular localization. In chronic demyelinating neuropathy with anti-nodal/paranodal CNTN1, NFS-155, and CASPR1 antibodies, myotonia with anti-VGKC LGI1 or CASPR2 antibodies, or autoimmune autonomic neuropathy with anti-gAChR antibodies, the response to complement inhibitory agents would depend on the extent to which the antibodies exert their effects through complement dependent or independent mechanisms. Complement is also likely to play a role in Sjogren's, vasculitic, and cryoglobulinemic neuropathies.

Skin Responses in Newly Diagnosed Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal Gammopathy, and Skin Changes (POEMS) Syndrome After Therapy With Low-Dose Lenalidomide Plus Dexamethasone

Background

Polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes (POEMS) syndrome is a rare paraneoplastic disease with a high prevalence of skin symptoms. Few studies have focused on skin responses to systemic treatment of this disease.

Objective

To evaluate skin responses after treatment with low-dose lenalidomide plus dexamethasone and determine their relationship with vascular endothelial growth factor (VEGF) and hematological responses.

Methods

A total of 41 consecutive Chinese patients who were at least 18 years of age with newly diagnosed POEMS syndrome were enrolled. 36 of them completed 12 cycles of treatment. Skin, serum VEGF, hematological and neurological responses were documented at 1, 2, 3, 6, 9, and 12 months during treatment.

Results

Skin manifestations were not associated with serum VEGF levels at baseline. Of the patients with hyperpigmentation, hemangiomas, hypertrichosis, white nails, or acrocyanosis separately, 26/34 (76.5%), 11/30 (36.7%), 14/15 (93.3%), 21/21 (100%), and 4/4 (100%) achieved complete responses at 12 months. Reduction in hyperpigmentation after 12 months reflected a good VEGF response (P = 0.017).

Conclusion

Low-dose lenalidomide plus dexamethasone therapy is effective in reversing skin changes in patients with POEMS syndrome.

Clinical Trial Registration

Clinicaltrials.gov, identifier NCT01816620

The Wide Spectrum of Pathophysiologic Mechanisms of Paraproteinemic Neuropathy

Monoclonal gammopathy is encountered quite frequently in the general population. This type of hematologic abnormality may be mild, referred to as monoclonal gammopathy of undetermined significance or related to different types of hematologic malignancies. The association of a peripheral neuropathy with monoclonal gammopathy is also fairly common, and hemopathy may be discovered in an investigation of peripheral neuropathy. In such a situation, it is essential to determine the exact nature of the hematologic process in order not to miss a malignant disease and thus initiate the appropriate treatment (in conjunction with hematologists and oncologists). In this respect, nerve biopsy (discussed on a case-by-case basis) is of great value in the management of such patients. We therefore propose to present the objectives and main interests of nerve biopsy in this situation.

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.