Deep characterization of the anti-drug antibodies developed in Fabry disease patients, a prospective analysis from the French multicenter cohort FFABRY

Abstract

BackgroundFabry disease (OMIM #301500) is an X-linked disorder caused by alpha-galactosidase A deficiency with two major clinical phenotypes: classic and non-classic of different prognosis. From 2001, enzyme replacement therapies (ERT) have been available. We aimed to determine the epidemiology and the functional characteristics of anti-drug antibodies. Patients from the French multicenter cohort FFABRY (n = 103 patients, 53 males) were prospectively screened for total anti-agalsidase IgG and IgG subclasses with a home-made enzyme-linked immunosorbent assay (ELISA), enzyme-inhibition assessed with neutralization assays and lysoGb3 plasma levels, and compared for clinical outcomes.ResultsAmong the patients exposed to agalsidase, 40% of men (n = 18/45) and 8% of women (n = 2/25) had antibodies with a complete cross-reactivity towards both ERTs. Antibodies developed preferentially in men with non-missense GLA mutations (relative risk 2.88, p = 0.006) and classic phenotype (58.6% (17/29) vs 6.7% (1/16), p = 0.0005). Specific anti-agalsidase IgG1 were the most frequently observed (16/18 men), but the highest concentrations were observed for IgG4 (median 1.89 μg/ml, interquartile range (IQR) [0.41–12.24]). In the men exposed to agalsidase, inhibition was correlated with the total IgG titer (r = 0.67, p < 0.0001), especially IgG4 (r = 0.75, p = 0.0005) and IgG2 (r = 0.72, p = 0.001). Inhibition was confirmed intracellularly in Fabry patient leucocytes cultured with IgG-positive versus negative serum (median: 42.0 vs 75.6%, p = 0.04), which was correlated with IgG2 (r = 0.67, p = 0.017, n = 12) and IgG4 levels (r = 0.59, p = 0.041, n = 12). Plasma LysoGb3 levels were correlated with total IgG (r = 0.66, p = 0.001), IgG2 (r = 0.72, p = 0.004), IgG4 (r = 0.58, p = 0.03) and IgG1 (r = 0.55, p = 0.04) titers. Within the classic group, no clinical difference was observed but lysoGb3 levels were higher in antibody-positive patients (median 33.2 ng/ml [IQR 20.6–55.6] vs 12.5 [10.1–24.0], p = 0.005).ConclusionAnti-agalsidase antibodies preferentially develop in the severe classic Fabry phenotype. They are frequently associated with enzyme inhibition and higher lysoGb3 levels. As such, they could be considered as a hallmark of severity associated with the classic phenotype. The distinction of the clinical phenotypes should now be mandatory in studies dealing with Fabry disease and its current and future therapies.

Dose-Dependent Effect of Enzyme Replacement Therapy on Neutralizing Antidrug Antibody Titers and Clinical Outcome in Patients with Fabry Disease

“…In this study, our focus was on neutralizing ADAs, but a humoral response can include the formation of neutralizing and non-neutralizing antibodies, which has been confirmed by a recent study in affected patients with FD. 19 Because IgG-tagged ERT molecules are also internalized and digested by macrophages, 4 future studies are warranted to analyze a potential effect of neutralizing as well as non-neutralizing ADAs on cellular ERT uptake of antigen-ADA complexes in macrophages (for elimination) and endothelial cells (for lysosomal Gb3 clearance).…”

Strong increase of leukocyte apha‐galactosidase A activity in two male patients with Fabry disease following oral chaperone therapy

“…Leukocyte α‐Gal A activity was measured 1 hr before ERT infusion, and between 24 and 48 hr of the last intake of migalastat. Plasma lyso ‐Gb3 was measured using liquid chromatography coupled to mass spectrometry, with glycinated lyso ‐Gb3 as internal standard (normal range <0.8 nmol/L) as previously described by Mauhin et al, (). The GLA mutations were identified using Sanger sequencing.…”

Neutralizing anti-drug antibodies in Fabry disease have no obvious clinical impact?

“…With great interest we read the recent paper by Mauhin and colleagues entitled “Deep characterization of the anti-drug antibodies developed in Fabry disease patients, a prospective analysis from the French multicenter cohort FFABRY” [ 1 ]. The authors presented a detailed characterization of anti-drug antibodies (ADAs) in patients with Fabry disease, confirmed their frequency of 40% in men treated with agalsidase and complete cross reactivity against agalsidase alfa and beta and an unambiguous association with lyso-Gb3 considered as a hallmark of disease severity [ 1 ]. Nevertheless, they came to the conclusion that “anti-agalsidase antibodies have no obvious clinical impact”.…”