Long-term effect of antibodies against infused alpha-galactosidase A in Fabry disease on plasma and urinary (lyso)Gb3 reduction and treatment outcome.

INTRODUCTION: Enzyme replacement therapy (ERT) with alpha-Galactosidase A (aGal A) may cause antibody (AB) formation against aGal A in males with Fabry disease (FD). Anti agalsidase ABs negatively influence globotriaosylceramide (Gb3) reduction. We investigated the impact of agalsidase AB on Gb3 and lysoGb3 and clinical outcome in Fabry patients on ERT. METHODS: Adult male and female patients on ERT for at least one year were included. Urinary Gb3 was measured by HPLC, plasma lysoGb3 by LC-ESI-MS/MS and AB with a neutralization assay. RESULTS: Of the 59 patients evaluable patients, 0/30 females and 17/29 males developed anti-agalsidase antibodies (AB+). Only 3/17 males had transient (low) titers (tolerized). All AB+ patients developed antibodies during the first year of treatment. Change of agalsidase preparation (or dose) did not induce antibody formation. AB+ males had significant less decline in plasma lysoGb3 compared to AB- males (p = 0.04). Urinary Gb3 levels decreased markedly in AB- but remained comparable to baseline in AB+ males (p<0.01). (Lyso)Gb3 reduction in plasma and urine on ERT was correlated with LVmass reduction in females and development white matter lesions and stroke. CONCLUSION: In male patients antibodies against aGal A remained present up to 10 years of ERT. The presence of these antibodies is associated with a less robust decrease in plasma lysoGb3 and a profound negative effect on urinary Gb3 reduction, which may reflect worse treatment outcome.

Identity of the activator proteins for the enzymatic hydrolysis of sulfatide, ganglioside GM1, and globotriaosylceramide.

The activator protein for the enzymatic hydrolysis of sulfatide, ganglioside GM1, and globotriaosylceramide was purified from human kidney, brain, and urine. As far as they could be assayed, these three activities cochromatographed during all steps, indicating that they are due to the same protein. This result was corroborated by immunochemical comparison of individually purified activator preparations. In contrast, the activator for ganglioside GM2 hydrolysis could clearly be separated from the other activities. Kinetic data were determined for the interaction of the sulfatide activator with the different glycolipids and hydrolases.

Immunohistochemical localization of glycosphingolipid in urinary renal tubular cells in Fabry's disease.

Although the accumulation of neutral glycosphingolipid (GSL), principally globotriaosylceramide ( GbOse3Cer ), in the kidney of patients with Fabry's disease is well documented, little is known about the type and quantity of lipid present in the renal tubular cells shed in the urine. Using a variety of cytologic technics, the authors examined exfoliated cells found in the urine specimens of patients hemizygous and heterozygous for alpha-galactosidase A deficiency. Renal tubular cells contained periodic acid- Shiff positive material that could be identified easily by Papanicolaou stain. A fluorescein-labeled antibody specific for GbOse3Cer localized this lipid to the cytoplasm. Electron microscopy showed numerous electron-dense multilamellar membranous inclusions within phagolysosomes and electronlucent material within lysosomes of tubular cells. Based on immunofluorescence, heterozygote individuals had similar distribution but less quantity of cytoplasmic GSL. The authors conclude that in Fabry's disease GSL accumulates probably in lysosomes of renal tubular cells. These cells are exfoliated and can be identified specifically in voided urine specimens. Examination of renal tubular cells in urine using the fluorescein antibody technic described here affords a noninvasive means of diagnosing and following the effect of therapy in patients with Fabry's disease.