Do IgG Level Variations in CIDP and MMN Patients Following Initial Intravenous IVIg Treatment Correlate With Ultimate Dosing

CIDP and MMN are part of a group of chronic inflammatory conditions that affect the peripheral nervous system. In CIDP, there is chronic inflammation of the peripheral nerves and nerve roots leading to demyelination. The myelin sheath is vital in the rapid propagation of nerve impulses between the central nervous system and the peripheral sensory receptors and muscles. By definition CIDP must progress over 8 or more weeks and can either have a slowly progressive disease course or a relapsing course with periods of improvement. Patients typically present with a non-length dependent neuropathy that affects motor (i.e. weakness of proximal or distal muscles, fatigue, swallowing difficulty, double vision, breathing difficulties etc) and sensory function. MMN is a similar condition to CIDP. It is an autoimmune demyelinating neuropathy that leads to slowly progressive asymmetrical weakness that worsens over years without treatment. IVIg is a recognised treatment for CIDP and MMN. A standard starting dose of 2 g/kg/course, spread over 2-5 days, has been widely used in both research and clinical practice. Due to the chronic nature of CIDP and MMN, most patients with these conditions require repeated doses to avoid relapse, but the frequency of courses and the total dose of IVIg per course required to achieve a steady state varies between patients. Given the modest risks involved with IVIg and its cost, the lowest possible dose and frequency of administration are preferred. Current strategies to reduce dose and frequency involve assessing clinical response to lower doses, but this is both time consuming and imprecise.