GD patients cannot produce the enzyme needed to process glucocerebroside, which is produced when old blood cells disintegrate. Without being processed, the substance instead builds up at dangerous levels in bone marrow and the cells of solid organs. The research team reports that the cellular environment consisting of both donor and recipient cells was instrumental in improving metabolic function in the three transplant recipients. Glycogen storage disease recipients of successfully engrafted livers were chimeras whereby the cells comprising the host organs had become mixed with cells of donor genome that had migrated diffusely from the allograft into the recipient tissues and apparently served as enzyme carriers. Chimerism, which represents the mutual coexistence of both recipient and donor cells, recently has been observed by the Pitt researchers in other transplant recipients and is believed to be necessary for graft acceptance.
Leukocytes are white blood cells.
Lymphocytes are a particular leukocyte important to the immune response, while macrophages are immune system cells that can devour microbes or can recognize and present antigens to other immune system cells. Evidence of chimerism and metabolic function were determined by analyzing and comparing biopsy results obtained at the time of transplantation and at various time periods following transplantation. In the first GSD patient, heart tissue biopsies taken 14 months after liver transplantation showed significant reductions in amylopectin deposits, from 13 to 5.9 percent, and a further reduction to less than one percent occurred over the next 22 months. The heart of the second GSD patient was almost amylopectin-free when it was first biopsied more than five years after liver transplantation and remained clean for 91 months. After liver transplantation, which was performed for hepatic failure in our patient with Gaucher's disease, we assumed that the disease would progress, prompting a decision for enzyme therapy.