Objective To evaluate the clinical and pathological correlations characterising each clinical subtype of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).
Methods We assessed 106 consecutive patients who had CIDP fulfilling the European Federation of Neurological Societies and Peripheral Nerve Society criteria and had been referred for sural nerve biopsy. Patients with anti-neurofascin 155, anti-contactin 1 and anti-LM1 antibodies were excluded.
Results 55 patients were classified as having typical CIDP. Regarding atypical CIDP, the multifocal acquired demyelinating sensory and motor (MADSAM) (n=15), distal acquired demyelinating symmetric (DADS) (n=16) and pure sensory (n=15) forms were major subtypes, while the pure motor (n=4) and focal (n=1) forms were rare. Nerve conduction studies revealed that distal motor latencies and F-wave latencies were markedly prolonged in the typical CIDP group but relatively preserved in the MADSAM group. Motor conduction velocity was conspicuously slowed in the DADS group, and distal motor latencies were markedly prolonged in the pure sensory group. Sural nerve biopsy specimens from patients with MADSAM, DADS and pure sensory type tended to show extreme variation in myelinated fibre density among fascicles due to focal myelinated fibre loss or onion-bulb formation, whereas patients with typical CIDP tended to show mild fascicular variation. Epineurial lymphocytic infiltration was conspicuous in cases with marked fascicular variation in myelinated fibre density.
Conclusions Preferential involvement of distal and proximal segments and uniform pathological features in typical CIDP indicate a role of humoral factors at sites where the blood–nerve barrier is deficient. By contrast, focal lesions in MADSAM, DADS and pure sensory forms may share neuropathic mechanisms primarily affecting the nerve trunk.
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Correction notice This article has been corrected since it was published Online First. Figures have been enlarged for clarity.
Contributors SI, HK and GS developed the concept and design of the article. SI, HK, RN, YK, MI, MK and GS compiled and analysed the data. MK and GS performed critical revision of the manuscript for important intellectual content. SI and HK wrote the first draft, and all authors critically evaluated the manuscript.
Funding This work was supported by grants from the Ministry of Health, Labor and Welfare (Research on rare and intractable diseases, H29-022) and the Ministry of Education, Culture, Sports, Science and Technology (17K09777) of Japan.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval Ethics Committee of Nagoya University Graduate School of Medicine.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request.
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