IgM anti-GM2 antibodies in patients with multifocal motor neuropathy target Schwann cells and are associated with early onset.

Background: Multifocal motor neuropathy (MMN) is a rare, chronic immune-mediated polyneuropathy characterized by asymmetric distal limb weakness. An important feature of MMN is the presence of IgM antibodies against gangliosides, in particular GM1 and less often GM2. Antibodies against GM1 bind to motor neurons (MNs) and cause damage through complement activation.

Acute facial nerve palsy in children in a Lyme disease-endemic area in the Netherlands.

We assessed the prevalence of Lyme neuroborreliosis in children with acute facial nerve palsy in a Lyme-endemic region and patient characteristics associated with this. All children visiting one of three participating hospitals between January 2010 and December 2016 were included in the study. Of 104 children referred to the hospital with facial nerve palsy, 43% had Lyme neuroborreliosis and 57% idiopathic facial palsy.

High-resolution mapping identifies HLA class II associations with multifocal motor neuropathy.

Objective: To gain further insight in the immunopathology underlying multifocal motor neuropathy (MMN) by exploring the association between MMN and the human leukocyte antigen (HLA) class II DRB1, DQB1, and DQA loci in depth and by correlating associated haplotypes to detailed clinical and anti-ganglioside antibody data.

Methods: We performed high-resolution HLA-class II typing for the DRB1, DQB1, and DQA1 loci in 126 well-characterized MMN patients and assessed disease associations with haplotypes. We used a cohort of 1305 random individuals as a reference for haplotype distribution in the Dutch population.

Clinical outcomes in multifocal motor neuropathy: A combined cross-sectional and follow-up study.

Objective: To assess the clinical course of multifocal motor neuropathy (MMN) in a large cohort of patients and to identify predictive factors of a progressive disease course.

Methods: Between May 2015 and February 2016, we collected clinical data from 100 patients with MMN, of whom 60 had participated in a nationwide cross-sectional cohort study in 2007. We documented clinical characteristics using standardized questionnaires and performed a standardized neurologic examination.

Serum cytokine patterns in immunoglobulin m monoclonal gammopathy-associated polyneuropathy.

Introduction: Polyneuropathy with immunoglobulin M monoclonal gammopathy (IgM-PNP) is associated with the presence of IgM antibodies against nerve constituents such as myelin associated glycoprotein (MAG) and gangliosides.

Methods: To test whether B-cell-stimulating cytokines are increased in IgM-PNP, we measured serum concentrations of 11 cytokines in 81 patients with IgM-PNP and 113 controls.

Results: Median interleukin (IL)-6 concentrations were higher in patients with IgM-PNP, and median IL-10 concentrations were higher in the subgroup with anti-MAG IgM antibodies.