Association of neurofascin IgG4 and atypical chronic inflammatory demyelinating polyneuropathy: A systematic review and meta-analysis

Background: Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is the most commonly observed phenotype among chronic acquired demyelinating polyneuropathies and is clinically variable. The aim of this meta-analysis was to evaluate the diagnostic value and characteristics of CIDP targeting neurofascin 155 (NF155). Methods: A systematic literature search was performed on March 2018, and two reviewers independently extracted data and assessed the risk of bias on MEDLINE, EMBASE, the Web of Science, and the Cochrane Library to identify relevant articles. Results: Ten articles for the NF155 protein test with 1,161 patients and 1,636 controls were identified. The results showed that the pooled sensitivity was 0.09 (95% CI: 0.06-015), and specificity was 1.00 (95% CI: 0.98-1.00) of the NF155 for CIDP. The meta-analysis revealed that the sensory ataxic occurrence rate (OR: 10.79, 95% CI: 5.24-22.22) and tremor occurrence rate (OR: 6.71, 95% CI: 3.37-13.39) were higher among patients positive for NF155 compared with NF155-negative CIDP patients. However, the rate of good treatment response to intravenous immunoglobulin (IVIg) (OR: 0.09, 95% CI: 0.02-0.42) was lower in NF155-positive CIDP patients. Conclusions: NF155 is a specific protein marker for CIDP, but its diagnostic value has been questioned due to low sensitivity. However, as an antibody against paranodal antigens, NF155 seems more valuable in defining clinical subsets of CIDP.