Clearence of Gb3 from endothelial vessels of ocular conjunctiva in Fabry patients treated with agalsidase alfa

ROZENFELD P,; EBNER R,; CROXATO R,; CARLOS ALBERTO FOSSATI

Valencia

Congreso; 5th. Internacional Symposium on Lysosomal Storage Diseases; 2005

INTRODUCTION. Fabry?s disease is an X-linked inborn metabolic error caused by a deficiency of lysosomal a-galactosidase A. Globotriaosylceramide (Gb3) accumulates in lysosomes of various cells. At the moment, enzyme replacement therapy is the only available specific treatment for Fabry patients. Enzyme infusions reduced the content of plasma, urine sediment and tissue Gb3. In a previous work, we reported the development of a method to detect specifically Gb3 deposits by immunofluorescence in conjunctival biopsies. AIMS: The aim of this work is to evaluate the clearance of Gb3 in cells from the conjunctiva in Fabry patients treated with agalsidase alfa. METHODS: Conjunctival biopsies were obtained from 3 hemizygous and 2 heterozygous, before and after 6 months of treatment with agalsidase alfa. The specimens were processed for direct immunofluorescence using an anti-Gb3 monoclonal antibody and light microscopy using a mouse polyclonal antisera specific for a-galactosidase A. RESULTS: Positive immunofluorescence was not observed in cells from blood vessels from the patients after 6 months of treatment, as compared with the specimens before the treatment. We could detect the presence of Gb3 in stromal or macrophage cells, that are away of the blood vessels, where the enzyme is circulating. The staining specific for a-galactosidase A revealed the presence of this protein in the tissue from patients after treatment, but not before it. CONCLUSIONS. Agalsidase alfa could eliminate Gb3 deposits from the cells of the wall of blood vessels in patients with 6 months of treatment. The deposits in stromal cells were not removed, probably, because the enzyme must diffuse in the tissue to achieve those cells and/or of the short time of therapy. This method may be useful to evaluate effectiveness in the follow-up of patients under enzyme replacement therapy.