S6-4. CIDP syndrome with anti-NF155 and -CNTN1 IgG4 antibodies

Abstract

In recent years, the specific autoantibodies for some CIDP patients groups have been found. Neurofascin155 (NF155) and contactin-1 (CNTN1), which are adhesion molecules at paranodal axo-glial junction, are the novel target antigens. The patients with anti-NF155 and-CNTN1 IgG4 antibodies might form specific clinical subgroups. In 2013, Querol et al. found anti-CNTN1 IgG4 antibodies in 3 of 46 patients with CIDP. Subsequent studies showed the positivity rate of anti-CNTN1 IgG4 antibodies in CIDP as 2.4–7.5%. The characteristic features of the patients with anti-CNTN1 IgG4 antibodies were; relatively older onset, subacute course, severe disability, poor response to IVIg, and remarkable sensory ataxia or tremor. In 2014, Querol et al. reported four CIDP patients with anti-NF155 IgG4 antibodies, who showed relatively younger onset, remarkable tremor and sensory ataxia, and poor response for IVIg. Subsequent studies showed similar clinical features. Positivity rates of anti-NF155 IgG4 antibodies in CIDP were reported as 3.7–18%. Pathology studies showed paranodal detachment of myelin terminal loop and axolemma. The optimal treatment for both conditions is still unknown. IVIg is insufficient, but some patients shows partial response. In refractory cases, plasma exchange or rituximab should be considered. Fast decision may be required for preventing irreversible axonal damage.