Pathology of the liver in mucopolysaccharidosis: light and electron microscopic assessment before and after bone marrow transplantation.

Serial liver biopsies were obtained in 20 patients undergoing bone marrow transplantation (BMT) for mucopolysaccharidosis (MPS). The 13 patients with MPS I, one with MPS II, four with MPS III, and two with MPS VI underwent liver biopsy prior to and from 1 to 37 months after BMT. The amount of accumulated glycosaminoglycan (GAG) was assessed by semiquantitation of Kupffer cell staining with colloidal iron and by counting the number of hepatocellular GAG-containing lysosomes in electron micrographs. Eleven of 13 patients with MPS I achieved engraftment, and 10 of the 11 cleared the Kupffer cells and hepatocytes of GAG by 3 to 19 months post-BMT. Two patients with autologous recovery demonstrated persistent hepatocyte inclusions. The three patients with MPS II and MPS VI engrafted and showed clearance of hepatocyte and Kupffer cell GAG by 7 months after BMT. All four patients with MPS III engrafted. Although the Kupffer cells in these patients were cleared of GAG by 12 months after BMT, hepatocellular inclusions persisted in all four. For MPS I, II and VI, donor engraftment was associated with resolution of lysosomal storage material in donor-derived Kupffer cells and untransplanted hepatocytes, indicative of transcellular metabolic correction. Failure of hepatocyte clearance in one case of MPS I and all patients with MPS III suggested a diminished capacity of the graft-derived enzyme to enter the hepatocyte lysosomes in these patients.

Determination of urinary homovanillic and vanillylmandelic acids from dried filter paper samples: assessment of potential methods for neuroblastoma screening.

Urinary homovanillic (HVA) and vanillylmandelic (VMA) acids were analyzed on 200 random urine samples from patients with neuroblastoma and controls, after the samples had been dried onto absorbent filter paper. The acids were determined quantitatively by gas chromatography (GC) and qualitatively by thin layer chromatography (TLC). The results were analyzed for correlation between liquid urine samples and urine dried on filter paper and between TLC and GC methods. A high overall correlation for HVA and VMA (99%) was found between liquid and dried filter samples analyzed by GC. The correlations were more significant for samples with elevated levels of these acids than for those with normal levels. Normalization of the results to the urinary creatinine concentration (UCr) is indicated due to variations in urine concentration. Results from TLC analysis showed a false positive rate of 3.5% and a false negative rate of 0.5% compared to GC analysis. This work suggests that a combination of a sensitive TLC method with a rapid quantitative GC method would be suitable for mass neuroblastoma screening in infants.

Assessment of the diurnal variations in urinary homovanillic and vanillylmandelic acid excretion for the diagnosis and follow-up of patients with neuroblastoma.

The diurnal variation of urinary homovanillic acid (HVA) and vanillylmandelic acid (VMA) was studied in neuroblastoma patients and in a control group. Urinary HVA and VMA levels in four sequential 6-hour urine collections within a 24-hour period were compared. HVA and VMA levels were expressed in microgram/mg of urinary creatinine (UCr) and in mg/6h specimens. No statistically significant variations between the four time intervals were found when expressed in microgram/mg UCr or mg/6h. The small variations that exist in the excretion of HVA and VMA during different periods of the day are due to variations in renal excretion rather than variations in production. The results from this study indicate that a random urine sample should be as good as a 24-hour collection for diagnosis and follow-up of neural crest tumors.

Pretransplant conditioning with busulfan (Myleran) and cyclophosphamide for nonmalignant diseases. Assessment of engraftment following histocompatible allogeneic bone marrow transplantation.

Four pediatric patients with diseases potentially curable by bone marrow transplantation (BMT)--i.e., common variable immune deficiency, Wiskott-Aldrich Syndrome (WAS), mucopolysaccharidosis type VI, and mucopolysaccharidosis type I received a conditioning regimen consisting of busulfan and cyclophosphamide prior to BMT from HLA-identical, mixed leukocyte culture (MLC)-unreactive siblings. Only one of the four patients achieved full engraftment. Of the remaining three patients, one experienced failure of engraftment, and two had persistent mixed chimerism. Although no serious complications were directly related to the preparative therapy, the doses of busulfan and cyclophosphamide previously described to be adequate for conditioning children with WAS were completely effective in only one of three pediatric patients in this series. Despite a higher dose of busulfan (16 mg/kg), mixed chimerism was observed in a subsequent patient. Of 13 evaluable patients in the literature in whom busulfan and cyclophosphamide had been used as preconditioning regimens for a variety of nonmalignant conditions, eight demonstrated lack of complete and sustained engraftment. On the other hand, clinical improvement has accompanied partial engraftment in some cases. We conclude that additional immunosuppressive and/or myeloablative conditioning is necessary if complete engraftment is attempted in histocompatible allogeneic BMT for many of the nonmalignant disorders.