Compton Laura’s research while affiliated with Instituto Nacional de Neurología y Neurocirugía and other places

Introduction New fatigable weakness following IVIg administration, with improvement after PLEX, in an individual patient with severe, longstanding CIDP was observed on multiple occasions. Her serum displayed AChR antibody titre positivity.Therefore, we considered the possibility that (i) AChR antibodies are transmitted to patients with IVIg and (ii) the potential for clinically-significant effect. Methods Samples of IVIg batches with corresponding post-infusion serum samples from a random selection of patients from the inflammatory neuropathy cohort were tested for AChR antibody titres using ELISA. Case notes were reviewed for evidence of clinical relevance. Patch clamp examination of AChR activity on exposure to antibody positive IVIg samples is pending. Results All 20 IVIg samples had detectable levels of AChR antibodies. Mean (S.D.) titre was 2.2nmol/l (2.4), range: 0.21-9.4nmol/l. Mean (S.D.) mass of AChR antibodies in IVIg administered per cycle was 593ng (610), range: 33.3-2278ng. No post-infusion patient sera were positive. No clinical manifestations of myasthenia gravis were observed in this group. Conclusions Although detectable levels of AChR antibodies were found in IVIg samples, this did not result in clinically significant levels in patient sera or clinical manifestations in this small study. Molecular studies to explore potential for clinical impact are pending.