Acute demyelinating sensorimotor polyneuropathy in B‐cell lymphoma with IGM autoantibodies against glycolipid GD1B

A 20‐year‐old man developed weakness without sensory complaints ten days after rubella. Examination showed limb weakness and brisk tendon reflexes but no sensory abnormalities. Laboratory investigations revealed IgG and IgM anti‐Rubella and increased CSF protein content (0,8 g/L). Electrophysiological examination showed partial motor conduction blocks in eight nerves and normal sensory conductions even across the sites of CB. Brain and spinal cord MRI and SEPs were normal. The patient was treated with four plasmaphereses and fully recovered in six months. Conduction blocks gradually improved with increasing duration and abnormal temporal dispersion in proximal CMAPs. GBS has been rarely reported after rubella. Anti‐myelin basic protein antibodies have been found in a patient with a relapsing motor neuropathy following rubella vaccination. As antibodies cross‐reacted with a viral protein, molecular mimicry has been proposed as a pathophysiological mechanism. In our patient we did not find anti‐MBP antibodies and antibodies to‐glycolipids (GM1, GM2, GA1, GD1a, GD1b, GQ1b, sulfatides, galactocerebroside) were also negative. Indirect immunofluorescence after incubation of patient's serum on rabbit sciatic nerve and human sural nerve and roots was negative. Our patient confirms the occurrence of GBS following Rubella and shows some uncommon features: 1) hyperactive deep tendon reflexes; 2) demyelination selectively involving motor fibres; and 3) widespread early conduction blocks in intermediate nerve segments.