PROTOCOL OUTLINE: This is a randomized, double blind, placebo controlled study. Patients are randomized to treatment with low dose intravenous immunoglobulin (IVIg), high dose IVIg, or placebo.

Patients must first complete baseline evaluation. Patients receive IVIg or placebo on days 1, 2, 3, and 5, biweekly at weeks 2-4, weekly at weeks 5-8, and every other week at weeks 9-12.

Patients are assessed at 6, 12, 36, 52, and 104 weeks.

PROTOCOL ENTRY CRITERIA:

--Disease Characteristics--

• Diagnostically proven non-insulin dependent diabetes mellitus as defined by the following criteria: Presence of classic symptoms, such as polyuria, polydipsia, ketonuria, and rapid weight loss, together with plasma glucose elevations Elevated fasting glucose concentration on more than one occasion
• Diagnostically proven proximal diabetic neuropathy with any of the following symptoms: Severe thigh, hip, or leg pain Greater than 20% weight loss Progressive proximal weakness in the painful leg Weakness in the contralateral lower limb Thoracic or cervical root distribution Symmetric distal polyneuropathy or autonomic neuropathy may be mild or absent

--Prior/Concurrent Therapy--

• At least 6 months since prior immunosuppression or plasma exchange
• No history of prior renal transplant

--Patient Characteristics--

• Age: 18 and over
• Performance status: Gait impairment at least grade 2
• Hematopoietic: Not specified
• Hepatic: Not specified
• Renal: Creatinine no greater than 1.4 mg/dL (women) Creatinine no greater than 1.5 mg/dL (men) No history of renal failure
• Cardiovascular: No history of cardiac failure
• Neurologic: Normal nerve conduction studies or changes compatible with distal symmetric diabetic neuropathy or diabetic lumbosacral radioplexus neuropathy Spinal fluid cell count less than 5 cells/mm3 Normal cerebral spinal fluid cytology No structural spine disease No inherited neuropathy
• 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