Ultrasound and blood markers may unlock personalized treatment for rare nerve disease

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Male or female aged 18 years or older. * Diagnosis of CIDP according to the 2021 EAN/PNS criteria; eligible phenotypes include typical CIDP, asymmetric CIDP (MADSAM/Lewis-Sumner syndrome), and pure motor CIDP. Pure sensory CIDP is excluded. * Ability to undergo protocol assessments, including clinical evaluation, electrophysiological studies, nerve ultrasound, and blood sampling. * Ability to provide written informed consent. * Affiliation with a health insurance system or equivalent. Group 1-specific criteria: * Newly diagnosed CIDP. * No previous immunomodulatory treatment for CIDP before baseline study assessment. * Planned initiation of IVIg according to standard clinical practice. Group 2-specific criteria: * Established CIDP with persistent clinically relevant disability. * Documented inadequate, partial, transient, or absent response despite adequate prior therapy, according to the final refractory disease definition. * Stable treatment exposure before inclusion according to the final protocol. Exclusion Criteria: * Pure sensory CIDP. * Alternative cause of neuropathy, including hereditary, metabolic, toxic, or other acquired neuropathies judged to better explain the clinical picture. * Motor neuron disease, myopathy, neuromuscular junction disorder, or another neurological or neuromuscular condition interfering with clinical, electrophysiological, or ultrasound interpretation. * CIDP mimic or alternative diagnosis. * Active infection likely to influence study assessments. * Active malignancy or other major systemic condition likely to confound biomarker interpretation. * Concomitant autoimmune or inflammatory disease likely to materially influence cytokine or complement measurements. * Severe psychiatric or cognitive disorder interfering with participation. * Participation in another interventional trial when incompatible with the present protocol. * Inability or unwillingness to comply with study procedures.