Autoantibodies Against Dihydrolipoamide S-Acetyltransferase Are Not Associated With Immune-Mediated Neuropathies

Abstract

Objectives: Dihydrolipoamide S-acetyltransferase (DLAT), the E2 component of the mitochondrial pyruvate dehydrogenase complex (PDC-E2), has recently been suggested to be a biomarker of chronic inflammatory demyelinating polyneuropathy (CIDP). It was particularly associated with sensory variants of CIDP. Antimitochondrial antibodies are important for the diagnosis of primary biliary cholangitis, but insofar, only 2 studies have reported an association with CIDP. Here, we aimed to validate these observations in a cohort of French patients with immune-mediated neuropathy.

Methods: The positivity against PDC-E2/DLAT was examined using ELISA and confirmed using commercially available immuno-DOT and by indirect immunofluorescence on stomach, kidney, and liver sections.

Results: None of the 20 healthy controls, 31 patients with Guillain-Barré syndrome, 102 patients with CIDP (including 24 patients with sensory CIDP), 26 patients with monoclonal gammopathy, 23 patients with Charcot-Marie-Tooth disease, or 20 patients with autoimmune nodopathy showed IgG against PDC-E2/DLAT.

Discussion: PDC-E2/DLAT is accurately a target antigen in immune-mediated neuropathies.

Figure. Reactivity Against DLAT/PDC-E2 in Patients With Peripheral Neuropathy

The detection of autoantibodies was performed by ELISA on human DLAT/PDC-E2 protein. Twenty heathy controls (HCs), 26 monoclonal gammopathy (GAM), 23 Charcot-Marie-Tooth disease (CMT), 31 Guillain-Barré syndrome (GBS), 24 sensory chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), 20 distal acquired demyelinating symmetric neuropathy (DADS), 58 CIDP, and 20 autoimmune nodopathy (AN) were tested. As positive controls, 2 sera with antimitochondrial antibodies (AMAs) were used. The threshold of positivity is indicated by a dashed line. No significant reactivity was found in any groups (one-way ANOVA followed by Bonferroni post hoc tests).