Long-term effects of intravenous immunoglobulin in CIDP

Objective Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an acquired demyelinating disease of the peripheral nervous system characterized by muscle weakness, areflexia or hyporeflexia, and sensory disturbances. Although short-term efficacy of intravenous immunoglobulin (IVIg) has been demonstrated in randomized-controlled trials, the data pertaining to long-term outcome in CIDP are limited. Consequently, the aim of the present study was to assess the long-term effects of IVIg on neurophysiological parameters in CIDP. Methods Neurophysiological records from 11 CIDP patients, treated with IVIg for 12 months, were reviewed. Nerve conduction studies were assessed at baseline, 1-year, and last follow-up. Results There was a significant reduction in the frequency of conduction blocks (pre-treatment nerve segments affected 61%; last follow-up 39%, P < 0.01) and a reduction in ongoing axonal loss (pre-treatment regions with spontaneous activity, 47%; post-treatment 29%, P < 0.01) with IVIg treatment. Further, there was significant improvement in sensory nerve conduction studies with IVIg treatment (sensory amplitudes reduced pre-treatment, 90% nerves tested; post-treatment, 62%, P < 0.01). Conclusions The present study suggests that long-term IVIg maintenance therapy improves neurophysiological parameters in CIDP. However, CIDP patients remain IVIg dependent and new conduction blocks may develop. Significance The present study suggests that long-term IVIg maintenance therapy improves neurophysiological parameters in CIDP, possibly by reducing the immune response and thereby fostering nerve healing.