Chronic inflammatory demyelinating polyneuropathy (CIDP): change of serum IgG dimer levels during treatment with intravenous immunoglobulins.
BACKGROUND
Intravenous immunoglobulin (IVIg) is an effective treatment in chronic inflammatory demyelinating polyneuropathy (CIDP). In most patients, the optimal IVIg dose and regime is unknown. Polyvalent immunoglobulin (Ig) G form idiotypic/anti-idiotypic antibody pairs in serum and IVIg preparations. We determined IgG dimer levels before and after IVIg treatment in CIDP patients with the aim to explore their utility to serve as a surrogate marker for treatment response.


METHODS
IgG was purified from serum of five controls without treatment, as well as from serum of 16 CIDP patients, two patients with Miller Fisher syndrome (MFS), and one patient with myasthenia gravis before and after treatment with IVIg. IgG dimer levels were determined by size exclusion chromatography. IgG dimer formation was correlated with clinical response to IVIg treatment in CIDP. Re-monomerized IgG dimer fractions were analyzed for immunoreactivity against peripheral nerve tissue.


RESULTS
IgG dimer levels were significantly higher in post- compared to pre-IVIg infusion samples. Low post-treatment IgG dimer levels in CIDP patients were associated with clinical worsening during IVIg treatment. Re-monomerized IgG dimer fractions from CIDP patients showed immunoreactivity against peripheral nerve tissue, whereas similarly treated samples from MFS patients showed immunoreactivity against GQ1b.


CONCLUSIONS
Assessment of IgG dimer levels could be a novel approach to monitor CIDP patients during IVIg treatment, but further studies in larger cohorts are warranted to explore their utility to serve as a potential therapeutic biomarker for IVIg treatment response in CIDP.
Department of Neurology, University Hospital Cologne, Cologne, Germany. christian.ritter@uk-koeln.de.|Center of Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany. christian.ritter@uk-koeln.de.|Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Centre Jülich, Jülich, Germany. christian.ritter@uk-koeln.de.
Christian
C
Ritter
Department of Neurology, University Hospital Cologne, Cologne, Germany. ilja.bobylev@uk-koeln.de.|Center of Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany. ilja.bobylev@uk-koeln.de.
Ilja
I
Bobylev
Department of Neurology, University Hospital Cologne, Cologne, Germany. helmar.lehmann@uk-koeln.de.|Center of Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany. helmar.lehmann@uk-koeln.de.
Helmar C
HC
Lehmann
D000368:Aged; D015415:Biomarkers; D019281:Dimerization; D005260:Female; D005732:Gangliosides / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D016756:Immunoglobulins, Intravenous / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D019846:Miller Fisher Syndrome / Q000188:drug therapy / Q000276:immunology; D009157:Myasthenia Gravis / Q000188:drug therapy; D009412:Nerve Fibers / Q000276:immunology; D010525:Peripheral Nerves / Q000473:pathology; D020277:Polyradiculoneuropathy, Chronic Inflammatory Demyelinating / Q000097:blood / Q000276:immunology* / Q000473:pathology
D015415:Biomarkers; D005732:Gangliosides; D007074:Immunoglobulin G; D016756:Immunoglobulins, Intravenous; C039129:GQ1b ganglioside