AMNIOTIC EPITHELIAL CELL IMPLANTATION (AECI) IN LYSOSOMAL STORAGE DISEASES

Human amniotic epithelium expresses very low levels of HLA antigens on the cell surface and is non-immunogenic when implanted subcutaneously into normal recipients (Nature 295: 325, 1982). Amniotic epithelial cells also produce several lysosomal hydrolases (Lancet 2: 1003, 1981). We performed AECI as possible enzyme replacement therapy in 5 patients, ages 22 mos-7 yrs, with heritable storage diseases. One patient had Gm₁ gangliosidosis, two had Farber's disease, one had metachromatic leukodystrophy, and one had mucopolysaccharidosis I Hurler-Scheie compound. Human amnion was obtained from elective caesarean deliveries and implanted subcutaneously into recipients within 6 hr after procurement. All patients tolerated the implantation well. In the post-AECI period, serum and leukocyte samples were obtained from recipients and assayed for enzyme activity. Most patients also had quantitation of urinary substrate at selected times after AECI. All patients have been followed for 3-6 mos post implant. We have not detected any increased enzyme activity or alterations in urinary excretion of substrate after AECI, and no patient has demonstrated objective clinical improvement. In our experience, AECI is well tolerated but fails to provide a source of replacement enzyme in selected storage diseases.