Guillain-Barre syndrome (GBS) is an autoimmune polyradiculoneuropathy usually 
preceded by respiratory tract or gastrointestinal infection. The pathogenesis in 
GBS is based on molecular mimicry mechanism. Hansen's disease is common in India 
and is the most common infectious cause of neuropathy. We describe a 42-year-old 
man who was being treated for borderline tuberculoid leprosy and developed Type 
1 lepra reaction followed by GBS and responded to plasmapheresis. Lepra reaction 
may lead to exposure of neural antigens, resulting in autoimmune mechanism and 
demyelination of peripheral nerves.