1. Guillain-Barré syndrome.  This is a rare (affecting just 1 -2 people in 100,000) autoimmune disease in which the immune system attacks the myelin or outer covering of nerves (and sometimes the nerves themselves) of the peripheral nervous system.  The damage leads to tingling and weakness in the legs and can proceed to even life-threatening paralysis.  

Symptoms generally reach their most severe within days or weeks when they stabilize for a period of days, weeks or even months.  Most people recover from even the most severe cases, but recovery can take as little as a few weeks or as much as a few years.  The cause of the autoimmune response is unknown but it is sometimes triggered by infection, surgery or vaccination.  

One treatment for Guillain-Barre syndrome that can reduce symptoms and hasten recovery is high dose immunoglobulin therapy.

2. Chronic inflammatory demyelinating polyneuropathy. CIDP can be thought of us a chronic form of the autoimmune disorder Guillain-Barre syndrome caused by demyelination of peripheral nerves, resulting in loss of sensation, motor weakness, and sensory symptoms.

Its estimated prevalence ranges from 0.8 to 8.4 per 100,000 people. CIDP is often disabling with over 50% of patients having temporary disability and about 10% eventually becoming persistently disabled or dying because of the disease.

The cause of CIDP remains unknown, but there are data supporting an immune pathogenesis. Plasmapheresis (plasma exchange), oral corticosteroids and intravenous immunoglobulin (IVIg) therapy are effective treatments, but should be started early to avoid permanent nerve damage. 

Reference (
1.    Pithadia AB et al.; Guillain-Barre syndrome (GBS). Pharmacological Report 2010; 62: 220 – 232
2.    Köller H et al.; Chronic inflammatory demyelinating polyneuropathy. N Engl J Med.2005 Mar        31;352(13):1343-56.
3.    Mahdi-Rogers M et al.; Overview of the pathogenesis and treatment of chronic inflammatory demyelinating polyneuropathy with intravenous immunoglobulins. Biologics. 2010 Mar 24;4:45-9.
4.    E.Nobile Orazio. Intravenous immunoglobulin versus intravenous methylprednisolone for chronic inflammatory demyelinating polyradiculoneuropathy: a randomized controlled trial. Lancet Neurol 2012; 11 (6): 493-502