Second intravenous immunoglobulin dose in patients with Guillain-Barré syndrome with poor prognosis (SID-GBS): a double-blind, randomised, placebo-controlled trial. - Walgaard C; Jacobs BC; Lingsma HF; Steyerberg EW; van den Berg B; Doets AY; Leonhard SE; Verboon C; Huizinga R; Drenthen J; Arends S; Budde IK; et al. (The Lancet. Neurology, 2021)