Clinical Research Directory

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.