Chronic sensorimotor polyradiculopathy with antibodies to P2: an electrophysiological and immunoproteomic analysis.
In this study we report a patient with chronic progressive sensory ataxia, proximal weakness, immunoglobulin M (IgM) monoclonal gammopathy, and elevated protein levels in the cerebrospinal fluid, who showed a good response to prednisone. Electrophysiological study disclosed abnormalities predominantly of late responses (F waves and H reflexes), with no evidence of demyelination in the peripheral nerves, suggesting motor and preganglionic sensory nerve roots as the site of the lesion. An immune-mediated pathogenesis was considered and, to identify possible target antigens, we performed bidimensional electrophoresis and a Western blot study. Based on the suspected lesion site, we used human anterior and posterior root extracts. We identified IgM reactivity against peripheral nerve myelin protein P2. Enzyme-linked immunosorbent assay confirmed IgM reactivity toward one synthetic peptide from P2. To our knowledge, reactivity against P2 has not been reported previously in a paraproteinemic neuropathy. Furthermore, we demonstrated that bidimensional electrophoresis and Western blot of the tissue involved, as determined by clinical and electrophysiological studies, may be useful to establish clinical-immunological correlations in paraproteinemic neuropathies.
Neuromuscular Diseases Unit, Department of Neurology, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Avenue Sant Antoni Maria Claret 167, Barcelona, Spain. rrojas@santpau.cat
Ricard
R
Rojas-Garcia
Eduard
E
Gallardo
Carolina
C
De La Torre
Lara
L
Sanvito
Isabel
I
Illa
D000368:Aged; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D015153:Blotting, Western; D002908:Chronic Disease; D015180:Electrophoresis, Gel, Two-Dimensional; D004594:Electrophysiology; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008297:Male; D018996:Myelin P2 Protein / Q000235:genetics / Q000276:immunology*; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000235:genetics; D011128:Polyradiculopathy / Q000235:genetics* / Q000276:immunology* / Q000503:physiopathology; D011241:Prednisone / Q000627:therapeutic use; D040901:Proteomics; D013126:Spinal Nerve Roots / Q000473:pathology
D000893:Anti-Inflammatory Agents; D018996:Myelin P2 Protein; D009419:Nerve Tissue Proteins; D011241:Prednisone