Anti-natural octyl disaccharide-leprosy IDRI diagnostic (NDO-LID) antibodies as indicators of leprosy reactions and neuritis.

Background: Leprosy is a complex infectious and neurological disease caused by Mycobacterium leprae. Nerve damage is related to immunological hypersensitivity responses known as leprosy reactions (LRs). Diagnostic tools to predict LRs are not available. We hypothesized that natural octyl disaccharide-leprosy IDRI diagnostic (NDO-LID) would be helpful as an indicator of LRs and neuritis.
Methods: To assess the utility of NDO-LID in indicating reactions, ELISA were used to detect specific antibodies in serum samples from 80 Colombian leprosy patients (40 with and 40 without history of LRs). Responses were detected using a range of detection reagents detecting IgG, IgM or both isotypes.
Results: Patients with a history of LRs had an increased seropositivity rate for anti-NDO-LID antibodies compared to patients without (anti-NDO-LID protein A [p=0.02], IgG anti-NDO-LID [p=0.01] and IgM anti-NDO-LID [p=0.01]). Further analyses of patients with a history of LRs indicated that both seropositivity rate and magnitude of responses were elevated among patients with neuritis versus those without neuritis (anti-NDO-LID protein A [p=0.03], IgG anti-NDO-LID [p=0.001] and IgM anti-NDO-LID [p=0.06]). Conclusions: Our data indicate that testing for serum anti-NDO-LID antibodies can be a useful screen to identify patients at risk of developing LRs and neuritis.