Inhibition of lymphocytic neuropathy target esterase predicts the development of organophosphate-induced delayed polyneuropathy

Neuropathy Target Esterase (NTE) is the molecular target in the nervous system for organophosphorus esters (OP) when they cause delayed polyneuropathy. Some NTE activity was recently found also in blood lymphocytes. An unsuccessful suicide attempt with the widely used pesticide chlorpyrifos (0,0-diethyl-0-3,5,6,-trichloro-2-pyridyl phosphorothioate) is reported, where prior inhibition of lymphocytic NTE correlates with the delayed development of polyneuropathy. A 42-year-old man drank approximately 300 mg/kg chlorpyrifos. The subsequent severe cholinergic syndrome lasted for 17 days with varying degrees of severity. Thirty days after intoxication the clinical and electrophysiological examination of the peripheral nervous system was normal but lymphocytic NTE was about 60% inhibited. On day 43 the patient began to complain of paresthesia and leg weakness. Clinical examination, electrophysiology and a nerve biopsy revealed signs of a peripheral polyneuropathy, axonal in type. This case report indicates that measurement of lymphocytic NTE might be used as a clinical test to predict the development of OP-induced delayed polyneuropathy.