Affiliation:
1. Research and Development Division Japan Blood Products Organization Kobe Hyogo Japan
2. Pharmacovigilance Division Japan Blood Products Organization Minato‐ku Tokyo Japan
Abstract
AbstractBackground and ObjectivesIntravenous immunoglobulins (IVIgs) contain various autoantibodies, including those against glutamic acid decarboxylase (GADAb), a valuable biomarker of type 1 diabetes mellitus. Passive transfer of GADAb from IVIgs to patients poses a risk of misdiagnosis, and information on the specific titres of GADAb and their impact on diagnostic accuracy remains limited. This study aimed to provide further insights into the origin of GADAb detected in patient serum following IVIg infusion.Materials and MethodsGADAb titres in IVIg products from Japan and the United States were measured using enzyme‐linked immunosorbent assay‐based assays. For reliable quantification, GADAb titres in pooled plasma were quantified and compared with those in the IVIg products. The determined titres were used to estimate the likelihood of passively detecting acquired GADAb in individuals receiving IVIgs.ResultsGADAbs were prevalent in IVIg products; however, the titres varied significantly among different lots and products. Importantly, IVIg‐derived GADAb was estimated to remain detectable in patient serum for up to 100 days following a dosage of 2000 mg/kg.ConclusionClinicians should consider that IVIg preparations may contain GADAb, which can lead to false‐positive results in serological assays. Careful interpretation of the assay results is key to the definitive diagnosis of type 1 diabetes mellitus.