Pain and tingling may actually be coming from vasculitic neuropathy. This is a complication of autoimmune disease.

Have you ever thought about IVIG?

How high was your CRP? Is your ANA high? Have they biopsied blood vessels or done a skin biopsy for PN?

Kidneys do get hit hard by vasculitis and autoimmune disease in general. Neuropathy is underappreciated, and it is not uncommon with autoimmune disease.