- Other: Electromyographic evidence of proximal lower limb plexus OR Radicular denervation compatible with proximal diabetic neuropathy No other systemic disease or malignancy Normal IgA levels No chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) No systemic amyloidosis No monoclonal gammopathy associated neuropathy No history of allergy to serum products No selective cervical or root involvement without lower limb weakness No evidence of secondary diabetes