Clinical features and anti-neural reactivity in neuropathy associated withIgG monoclonal gammopathy of undetermined significance

Neuropathy has been frequently reported in patients with IgG monoclonal gam mopathy of undetermined significance (MGUS) but it is still unclear whether this association has clinical or pathogenetic relevance. In order to clari fy the possible role of IgG MGUS in the neuropathy we correlated the clinic al and electrophysiological features of the neuropathy with the duration an d anti-neural activity of the hi-protein in 17 patients with neuropathy and IgG MGUS. Ten patients (59%) had a chronic demyelinating neuropathy clinic ally indistinguishable from chronic inflammatory demyelinating polyneuropat hy (CIDP) while 7 (41%) had a predominantly sensory axonal or mixed neuropa thy. In 80% of patients in the CIDP-like and 28% in the sensory group the I gG M-protein became manifest several months to years after onset of the neu ropathy. Antibodies to one or more neural antigens (including tubulin, a 35 KD P0-like nerve myelin glycoprotein. GD1a, GM1 and chondrotin sulfate C) w ere found in 40% of patients with CIDP-like and 43% with sensory neuropathy but also in 37% patients with IgG MGUS without neuropathy. Neuropathy asso ciated with IgG MGUS is probably less heterogeneous than previously conside red suggesting that this association may not be merely casual. The evidence for primary pathogenetic role of IgG M-proteins in the neuropathy remains however elusive. (C) 1999 Elsevier Science B.V. All rights reserved.