Mobilization and selection of peripheral blood hematopoietic progenitors in children with systemic sclerosis

Background and Objective. Autologous transplant of lymphocyte-depleted peri pheral blood stem cells has been proposed for treatment of patients with se vere autoimmune disease. However, until now, no data are available on the s afety and feasibility of both stem cell collection and selection in pediatr ic patients with these disorders. We report on three children affected by s ystemic sclerosis with lung involvement, who received chemotherapy and gran ulocyte colony-stimulating factor (G-CSF) to mobilize autologous peripheral blood progenitors. Design and Methods. The priming regimen consisted of cyclophosphamide (CY, 4 g/m(2)) and G-CSF (lenograstim, 10 mu g/kg/day starting 2 days after cycl ophosphamide administration until stem cell collection). Leukapheresis was performed when WBC and CD34(+) cell count were at least 2x10(9)/L and 0.03x 10(9)/L, respectively. In the first patient, positive selection of CD34(+) cells was performed through the Ceprate SC stem cell concentrator (CellPro, Bothell, WA, USA). In the remaining 2 children, progenitor cells were also purged with negative selection of CD4(+) and CD8(+) lymphocytes performed by means of the Isolex 3001 device (Baxter). Results. All patients tolerated the priming regimen well and did not presen t any sign of autoimmune disease exacerbation. Collection was successful in all children and the number of CD34(+) cells before selection ranged betwe en 10.7x10(6) and 17.6x10(6)/kg of patient body weight. The selection of he matopoietic stem cells in the 3 patients resulted in at least 2.6-log T-cel l depletion of the cell content, with a recovery of the initial value of CD 34(+) cells comprised between 21 and 44%. After, a preparative regimen cons isting of CY (200 mg/kg over 4 days) and Campath-1 G in vivo (10 mg/day for 2 consecutive days), patients were transplanted using cryopreserved lympho cyte-depleted progenitor cells. In all cases, prompt hematopoietic engraftm ent was observed. Interpretation and Conclusions. Taken together these data suggest that mobi lization, collection and selection of hematopoietic progenitors are safe an d feasible in children with autoimmune disease. (C) 1999, Ferrata Storti Fo undation.