Reconstitution of lymphocyte subpopulations in children with inherited metabolic storage diseases after haematopoietic cell transplantation.

We prospectively evaluated the reconstitution of lymphocyte subpopulations in nine children with lysosomal diseases who underwent 11 allogeneic haematopoietic cell transplants (HCTs) following CD34(+) immunomagnetic enrichment, limited T-cell addback and in vivo B-cell depletion. Absolute lymphocyte count recovery was slow to cross the 5th percentile, occurring at a median of 10 months after HCT in patients with full chimaerism. Natural killer cells represented up to 90% of the total lymphoid population during the first 3 months. CD4(+) lymphocyte recovery occurred 9-18 months after HCT. In most patients, CD8(+) lymphocyte recovery was slow and comparable with that of CD4(+) lymphocytes. The CD4(+)/CD8(+) ratio normalised by 3-7 months after HCT in 50% of the patients. CD8(+) lymphocyte recovery was enhanced in patients with viral reactivation. Reconstitution of B-lymphocytes was particularly delayed in patients treated with rituximab. Declining chimaerism, rejection and viral reactivation were the most common problems in our series. Because of the unique graft manipulation, the pace of lymphocyte reconstitution was particularly slow, suggesting that these patients are at a significantly increased risk of infections for up to 2 years after HCT.

Renal transplantation in patients with Fabry disease.

Anderson-Fabry disease (AFd) is a rare X-linked disorder characterized by deficiency of alpha-galactosidase A that leads to systemic accumulation of neutral glycosphingolipids, predominantly globotriaosylceramide (Gb3), in body fluids and visceral tissues, including the kidney. End-stage renal failure is a common manifestation in hemizygous males that often occurs by the third to fourth decade of life. Usually transplanted patients exhibit improvement in clinical symptoms of the disease, probably related to the production of alpha-galactosidase A from the grafted kidney, but mainly related to the increase in Gb3 clearance by the functioning kidney, and increased survival of red cells due to the correction of the uremic status with an evident decrease in the production of Gb3 depending from hemolysis. Several Fabry patients with successful kidney graft survived for 10-15 years and died for cardiovascular complications related to the metabolic disease. The loss of grafted kidney is due to rejection, thrombosis or sepsis. An important issue considering renal transplantation in AFd is the recurrence of the disease in the kidney graft; however, no evidence regarding this possibility has occurred up to now. We report herein the ultrastructural study of the urinary sediment of a 35-year-old male Fabry patient with a severe clinical form of the disease with progression to ESRF at age 29, and submitted to renal transplantation at 33 years. Ultrastructural findings of the urinary sediment documented several cells, probably tubular epithelial cells, with typical accumulation of myelinic bodies resulting from intracellular storage of neutral glycosphingolipids. This morphological evidence arises the problem of the possible recurrence of AFd in the kidney graft in patients with severe phenotype of the metabolic disease.