Assessment of serum neurofilament light chains in leprosy associated peripheral neuropathy

Leprosy causes a peripheral sensory-motor neuropathy with affliction of sensory pathways usually preceding motor involvement. The nerve damage is a major cause of disability related to leprosy and contributes significantly to the stigma associated to the infection as well. Although effective multi drug therapy works to clear the bacterial load, the occurrence of peripheral neuropathy does not seem to be prevented and its occurrence, progression and recovery is unpredictable. Steroids are not uniformly effective in treating the peripheral neuropathy and newer drugs are urgently required to manage this distressing complication of leprosy.

Serum neurofilament light chains (NFL) were initially assessed in CSF in neurodegenerative disorders like Alzeihmer’s disease and multiple sclerosis. The significance in many such disorders is now well established and the marker is now used for treatment assessment in therapeutic trials of these diseases as well. With the advent of highly sensitive single molecular arrays (SIMOA), it is now possible to measure very small levels of NFLs in serum too. Further, in past few years the marker has been evaluated in some peripheral neuropathies also and shown to be of relevance. With this background we aim to assess serum NFL levels in patients with peripheral neuropathy of leprosy and compare it with levels in patients of leprosy without peripheral neuropathy, and healthy controls, to understand whether NFL can have a role in early detection of peripheral neuropathy of leprosy.