title: Polyneuropathy associated with IgG/IgA monoclonal gammopathy: a clinical and electrophysiological study of 15 cases.
abstract: Peripheral neuropathy has been widely reported in patients with monoclonal gammopathy (MG), more frequently immunoglobulin M (IgM) or IgG than IgA. Nevertheless, it remains unclear whether this association has clinical or pathogenic relevance. In order to clarify the possible role of IgG/IgA MG in neuropathy, we studied the clinical and electrophysiological features of 15 consecutive patients with polyneuropathy and IgG/IgA-MG, and compared them to those of 40 patients with polyneuropathy associated with IgM-MG, previously reported. Nine middle-aged patients (60%) had a chronic progressive or relapsing demyelinating polyneuropathy (DP) that was clinically and electrophysiologically indistinguishable from classic chronic inflammatory demyelinating polyneuropathy (CIDP) and frequently responded to immunosuppressive treatments, both characteristics supporting a dysimmune process. Six older patients (40%) had a chronic axonal distal polyneuropathy similar to the so-called chronic cryptogenic sensory polyneuropathy: there was no clear relationship with the MG in these patients and the response to immunosuppressive treatments was poor. Several features allowed us to distinguish between polyneuropathies associated with IgG/IgA-MG (IgG/IgA-PN) considered together and polyneuropathies associated with IgM-MG (IgM-PN). In the first group, the proportion of patients with a predominantly sensory clinical picture (27%) was less than that in the second group (75%), and there were fewer changes in nerve conduction studies. In addition, we found that the nine patients with DP associated with IgG/IgA-MG (IgG/IgA-DP) differed from the 31 with DP associated with IgM-MG (IgM-DP): clinical and electrophysiological studies clearly showed that the demyelinating pattern was more heterogeneous in IgG/IgA-DP than in IgM-DP. The spectrum of polyneuropathies associated with IgG/IgA-MG is heterogeneous, including DP, which is similar to classic CIDP, and axonal polyneuropathy, in which the pathogenic role of the MG remains elusive. In addition, IgG/IgA-DP differ from IgM-DP on clinical and electrophysiological grounds, suggesting probable different physiopathological mechanisms.
authors.affiliation: Service de Neurologie, CHU Dupuytren, Limoges, France.
authors.forename: L
authors.initials: L
authors.lastname: Magy
authors.forename: B
authors.initials: B
authors.lastname: Chassande
authors.forename: T
authors.initials: T
authors.lastname: Maisonobe
authors.forename: P
authors.initials: P
authors.lastname: Bouche
authors.forename: J-M
authors.initials: JM
authors.lastname: Vallat
authors.forename: J-M
authors.initials: JM
authors.lastname: Léger
mesh_terms: D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D018450:Disease Progression; D004594:Electrophysiology; D005260:Female; D006801:Humans; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000209:etiology; D009431:Neural Conduction / Q000502:physiology; D009483:Neuropsychological Tests; D010265:Paraproteinemias / Q000150:complications* / Q000503:physiopathology* / Q000628:therapy; D011115:Polyneuropathies / Q000209:etiology* / Q000503:physiopathology*; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D000305:Adrenal Cortex Hormones; D000893:Anti-Inflammatory Agents; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M