Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP) is an acquired neuropathy
characterized by an inflammatory multifocal segmental demyelination. Due to the clinical
heterogeneity of this condition and the lack of specific marker that can reliably identify
all patients, the diagnosis of CIDP remains difficult. Similarly, there are no clear factors
predicting the evolution or the prognosis of the disease. Current treatments are the
intravenous immunoglobulin (IVIg), corticoids and plasma exchange; IVIg therapy being the
most commonly used. Responses of the patients to the treatments are variable. Thus, it is
necessary to identify predictive markers of the therapeutic response of CIDP patients treated
Several potential biomarkers have been proposed recently, but none of them has yet been
validated as a predictive criterion for therapeutic response. It is therefore necessary to
continue to investigate several biological parameters to identify a reliable biological
In electromyography, the Motor Unit Number Index (MUNIX) technique allows measuring the
axonal loss by a precise count of functional motor units. This method, more sensitive than
the measure of the Compound Muscle Action Potential (CMAP), is rarely used in CIDP. MUNIX
might be a good tool to better characterize the patients and to follow the course of CIDP. It
also might be a new sensitive and reliable marker predictive of the therapeutic response.
Magnetic resonance Imaging (MRI) is increasingly used for the assessment of neuromuscular
diseases. A recent study on CIDP patients reported a significant decrease of the muscle
Magnetisation Transfer Ratio (MTR) compared to healthy subjects, correlated to clinical
parameters. The use of advances MRI techniques could allow characterizing the structure and
composition of muscle and nerve tissues of CIDP patients. It could also be a mean for
identifying potential new markers, largely unexplored until now, that might be sensitive to
disease course and/or IVIg response.
The objective of this study is to identify predictive markers of the treatment response of
CIDP patients receiving IVIg.
This is a prospective observational exploratory study of a cohort of 30 CIDP patients treated
with IVIg and followed-up during one year.