Modulatory effects on axonal function after intravenous immunoglobulin therapy in chronic inflammatory demyelinating polyneuropathy

Arch Neurol. 2011 Jul;68(7):862-9. doi: 10.1001/archneurol.2011.137.

Abstract

Objective: To investigate the immediate and longitudinal mechanisms of action of intravenous immunoglobulin (IVIg) on axonal function in chronic inflammatory demyelinating polyneuropathy (CIDP).

Design: Prospective single-center study.

Setting: Hospitals and outpatient clinics.

Participants: Clinical and functional assessment, nerve conduction studies, and 526 motor excitability studies were undertaken in 27 patients, matched before and immediately after infusion and followed up longitudinally.

Main outcome measures: Axonal excitability variables were measured before and immediately after infusion and compared with matched studies and findings in healthy controls.

Results: Immediately after infusion, patients demonstrated decreased threshold, with significant reduction in strength-duration time constant (P = .003), reduction in accommodation to depolarization (P = .04), and reduced threshold change during hyperpolarization (P = .003), accompanied by significant decreases in superexcitability (P = .03) and subexcitability (P = .02). In contrast, changes were absent in disease controls, confirming a specific IVIg action in CIDP patients. Longitudinally, changes correlated with clinical improvement (mean [SE] increase in the Medical Research Council sum score, 2.7 [0.7]; P = .005). Increased compound muscle action potential amplitude was associated with reduction in terminal latency (correlation coefficient, -0.65; P = .02). In addition, these changes translated into improvement in functional assessment with the adjusted Inflammatory Neuropathy Cause and Treatment score, which demonstrated a significant correlation with nerve excitability variables longitudinally (P = .01).

Conclusions: Findings from the present series establish a modulatory effect of IVIg on axonal function in CIDP patients, suggesting that IVIg stabilizes axonal membrane potential and promotes axonal recovery.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Axons / drug effects*
  • Axons / physiology*
  • Electric Stimulation / methods
  • Female
  • Humans
  • Immunoglobulins, Intravenous / therapeutic use*
  • Immunologic Factors / therapeutic use*
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Nervous System Physiological Phenomena / drug effects
  • Neural Conduction / drug effects
  • Polyradiculoneuropathy, Chronic Inflammatory Demyelinating / drug therapy*
  • Reaction Time

Substances

  • Immunoglobulins, Intravenous
  • Immunologic Factors