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Introduction: The efficacy of enzyme replacement therapy (ERT) with alglucosidase alfa for infantile-onset Pompe disease (IOPD) is limited in some patients due to the development of high and sustained antibody titers (HSAT; ≥12,800). Methods: We carried out detailed immunophenotyping of IOPD patients (n=40), including analysis of circulating cell populations by flow cytometry and plasma cytokines by multiplex array, to determine whether patients with HSAT have unique immunological characteristics compared to those with low titers (LT; <12,800). Results: Compared to patients with LT, patients who develop HSAT were skewed toward a type 2 immune profile, with an increased frequency of Th2 cells that was positively correlated with levels of Th2 (IL-4, IL-5, IL-13) and proinflammatory (IL-6, TNF-α, MIP-1α, MIP-1β) cytokines. B cells were increased in HSAT patients with a decreased fraction of unswitched memory B cells. Plasma GM-CSF concentrations were lower on average in HSAT patients, while CXCL11 was elevated. Finally, using principal components analysis, we derived an HSAT Signature Score that successfully stratified patients according to their antibody titers. Discussion: The immune profiles revealed in this study not only identify potential biomarkers of patients that developed HSAT but also provide insights into the pathophysiology of HSAT that will ultimately lead to improved immunotherapy strategies. [ABSTRACT FROM AUTHOR]

IntroductionThe efficacy of enzyme replacement therapy (ERT) with alglucosidase alfa for infantile-onset Pompe disease (IOPD) is limited in some patients due to the development of high and sustained antibody titers (HSAT; ≥12,800).MethodsWe carried out detailed immunophenotyping of IOPD patients (n=40), including analysis of circulating cell populations by flow cytometry and plasma cytokines by multiplex array, to determine whether patients with HSAT have unique immunological characteristics compared to those with low titers (LT;

White matter (WM) abnormalities and ventricular enlargement in brain MRI are well-known features in infantile-onset Pompe disease (IOPD) in the era of enzyme replacement therapy (ERT). In this multicentric observational retrospective study, we report a small cohort of IOPD subjects under ERT treatment (n = 5, median age at MRI = 7.4 years, median period of treatment = 85 months) that showed the classic features of extensive supratentorial WM abnormalities but also unusual findings such as early infratentorial WM abnormalities and late supratentorial U-fiber involvement. Given the recent implementation of ERT and the rarity of the disease, a complete spectrum of presentation and understanding of progressive pathology in the brain of IOPD subjects in treatment remains underacknowledged. The availability of long-term follow-up of IOPD subjects under ERT treatment allows a better insight into the evolution of brain abnormalities in such disease.

White matter (WM) abnormalities and ventricular enlargement in brain MRI are well-known features in infantile-onset Pompe disease (IOPD) in the era of enzyme replacement therapy (ERT). In this multicentric observational retrospective study, we report a small cohort of IOPD subjects under ERT treatment (n = 5, median age at MRI = 7.4 years, median period of treatment = 85 months) that showed the classic features of extensive supratentorial WM abnormalities but also unusual findings such as early infratentorial WM abnormalities and late supratentorial U-fiber involvement. Given the recent implementation of ERT and the rarity of the disease, a complete spectrum of presentation and understanding of progressive pathology in the brain of IOPD subjects in treatment remains underacknowledged. The availability of long-term follow-up of IOPD subjects under ERT treatment allows a better insight into the evolution of brain abnormalities in such disease. [ABSTRACT FROM AUTHOR]

Infantile-onset Pompe disease (IOPD) is a life-threatening multi-organ disease caused by an inborn defect of lysosomal acid α-glucosidase (GAA), which can degrade glycogen into glucose. Lack of GAA causes abnormal accumulation of glycogen in the lysosomes, particularly in the skeletal muscle, liver, and heart. Enzyme replacement therapy (ERT) with recombinant human GAA (rhGAA) is the only available treatment; however, its effect varies by organ. Thus, to fully understand the pathomechanism of IOPD, organ-specific disease models are necessary. We previously generated induced pluripotent stem cells (iPSCs) from three unrelated patients with IOPD and establish a skeletal muscle model of IOPD. Here, we used the same iPSC lines as the previous study and differentiated them into hepatocytes. As a result, hepatocytes differentiated from iPSC of IOPD patients showed abnormal accumulation of lysosomal glycogen, the hallmark of Pompe disease. Using this model, we also demonstrated that glycogen accumulation was dose-dependently restored by rhGAA treatment. In conclusion, we have successfully established an in vitro liver model of IOPD using patient-specific iPSCs. This model can be a platform to elucidate the underlying disease mechanism or to be applied to drug-screening. Moreover, our study also suggest that an iPSC-based approach is suitable for modeling of diseases that affect multiple organs like Pompe disease.