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Immune recovery was retrospectively analyzed in a cohort of 41 patients with acute leukemia, myelodysplastic syndrome and nonmalignant diseases, who received αβ T- and B-cell-depleted allografts from haploidentical family donors. Conditioning regimens consisted of fludarabine or clofarabine, thiotepa, melphalan and serotherapy with OKT3 or ATG-Fresenius. Graft manipulation was carried out with anti-TCRαβ and anti-CD19 Abs and immunomagnetic microbeads. The γδ T cells and natural killer cells remained in the grafts. Primary engraftment occurred in 88%, acute GvHD (aGvHD) grades II and III-IV occurred in 10% and 15%, respectively. Immune recovery data were available in 26 patients and comparable after OKT3 (n=7) or ATG-F (n=19). Median time to reach >100 CD3+ cells/μL, >200 CD19+ cells/μL and >200 CD56+ cells/μL for the whole group was 13, 127 and 12.5 days, respectively. Compared with a historical control group of patients with CD34+ selected grafts, significantly higher cell numbers were found for CD3+ at days +30 and +90 (267 vs 27 and 397 vs 163 cells/μL), for CD3+4+ at day +30 (58 vs 11 cells/μL) and for CD56+ at day +14 (622 vs 27 cells/μL). The clinical impact of this accelerated immune recovery will be evaluated in an ongoing prospective multicenter trial.

Conditioning including total body/lymphoid irradiation is widely used to prevent graft rejection in patients with refractory severe aplastic anemia (SAA) undergoing hemopoietic cell transplantation (HCT) from alternative donors and or after graft manipulation. To reduce regimen-related toxicity we transplanted three children with refractory SAA after conditioning with radiotherapy-free regimens. Conditioning included fludarabine 175-180 mg/m2 in all patients. In addition, patient 1 (failing two previous grafts) received thiotepa 10 mg/kg and Campath-1H 60 mg/m2; patient 2 cyclophosphamide 120 mg/kg, thiotepa 15 mg/kg and OKT-3 0.1 mg/kg/day for 4 weeks; and patient 3 cyclophosphamide 120 and ATG 90 mg/kg. Stem cell source was unmanipulated marrow from the same unrelated donor as for the two previous transplantations in patient 1 and CD34+-purified peripheral blood stem cells from an HLA-matched unrelated donor and from the haploidentical mother in patients 2 and 3. Only patient 1 received graft-versus-host disease (GVHD) prophylaxis with cyclosporine A and mycophenolate mofetil. Follow-up is now 30, 51, and 15 months. None of the patients developed GVHD. All patients have normal counts with complete donor chimerism. Fludarabine-based conditioning is powerfully immunosuppressive and may be used for children with refractory SAA undergoing HCT from alternative donors even after rejection following previous HCT.

Treatment with antibodies against T-lymphocytes usually triggers a febrile response potentially mimicking or masking infection. Procalcitonin (PCT) is considered a sensitive and specific marker of systemic bacterial and fungal infection. It was the aim of this study to investigate the characteristics of PCT and C-reactive protein (CRP) during treatment with polyclonal or monoclonal anti-T-cell antibodies, in order to examine the ability of these parameters to distinguish between systemic bacterial infection and reaction to antibody treatment. Thus, 15 consecutive febrile episodes after T-cell antibody infusion without clinical signs of infection were compared with nine episodes of Gram-negative sepsis. After T-cell antibody infusion PCT and CRP serum levels increased to a similar extent as in Gram-negative sepsis. Therefore, during T-cell antibody treatment neither PCT nor CRP are adequate for differentiating between fever due to infection or to unspecific cytokine release.

A paediatric patient was treated with orthotopic liver transplantation after he developed cirrhosis of the liver due to chronic graft-versus-host disease (GVHD) following allogeneic bone marrow transplantation. His pre-existing chronic GVHD of the skin disappeared and immunosuppressive therapy could be gradually tapered and finally withdrawn 71 months after liver transplantation. Two and a half years after discontinuation of all immunosuppressive therapy, the patient is in excellent condition with neither signs of chronic GVHD nor rejection of the liver graft.

Stem cell transplantation is the only curative approach to the treatment of Wiskott-Aldrich syndrome. However, using grafts from partially matched unrelated donors is associated with increased risk of graft rejection and graft-versus-host disease. In an attempt to prevent these problems, a 6-year-old boy with Wiskott-Aldrich syndrome lacking a suitable family donor, was transplanted with large numbers of unrelated highly purified CD34+ peripheral blood stem cells mismatched at one C locus. Conditioning consisted of busulfan 16 mg/kg body weight, cyclophosphamide 200 mg/kg body weight and antithymocyte globulin 20 mg/kg body weight x 3 days. The boy had a rapid hematopoietic engraftment and showed immunologic reconstitution by day +92. Although he did not receive prophylactic immunosuppression he did not develop any graft-versus-host disease and is well and alive up to now, 25 months after transplantation.

Three children with refractory severe aplastic anemia were transfused with high numbers of unrelated matched (n = 2) or C-locus haploidentical mismatched (n = 1) CD34-selected peripheral blood stem cells in the absence of an HLA-identical family donor. Two leukaphereses of the donors yielded a median number of 10.1 x 10(10) nucleated cells (range 9.7-15.4) with a median number of 9.89 x 10(8) CD34+ cells (range 7.46-26.1) and a median percentage of CD34+cells of 0.98% (range 0.77-1.7). After positive selection by magnetic cell sorting the patients received a median of 14.3 x 10(6) CD34+ cells/kg (range 11.7-24.3) and of 1.3 x 10(4) CD3+ cells/kg (range 0.57-5.8). Median time to ANC >/=0.5 x 10(9)/l was 7 days (range 7-12) and to platelets >/=20 x 10(9)/l 13 days (range 13-27). Chimerism analysis of peripheral blood after transplantation revealed permanent 100% donor hematopoiesis in all patients. The patient with the C-locus haploidentical mismatch presented with acute GVHD (grade III-IV) of the skin, liver and lower gastrointestinal tract (onset day +40) and died despite intensive immunosuppressive treatment on day +238. The two survivors developed lymphopoietic recovery of B and T lymphocytes within 3 months after transplantation. To our knowledge this experience represents the first report of transplantation with unrelated CD34+ enriched peripheral blood stem cell in children with refractory severe aplastic anemia. Bone Marrow Transplantation (2000) 25, 513-517.

We report two children who presented with cough and shortness of breath 7-8 months after a matched sibling stem cell transplant (SCT) for chronic myelogenous leukemia and myelodysplastic syndrome, respectively. Pulmonary function tests (PFTs) revealed severe airways obstruction (AO). However, radiographic investigations showed no serious abnormalities in the early phase and open lung biopsy revealed only mild lymphocytic bronchiolitis and bronchiolitis obliterans consistent with pulmonary graft-versus-host disease (GVHD). Despite administration of bronchodilators and various immunosuppressive agents obstructive lung disease progressed to pulmonary failure in patient 1, whereas stabilization of the clinical course was observed in patient 2. Serial PFTs were the best predictor of the clinical course in contrast to radiographic and histologic findings. It is concluded that PFTs should be performed repeatedly in pediatric patients after allogeneic SCT with the aim of diagnosing GVHD-associated AO in the subclinical phase. Progressive post-transplant AO necessitates prompt initiation of intensive immunosuppressive therapy in order to stop the underlying immunopathologic process even in the absence of severe radiographic and histologic findings.

A diagnosis of familial hemophagocytic lymphohistiocytosis (FHL) was established in an 18-month-old boy who presented with prolonged fever of unknown origin, severe pancytopenia, hepatosplenomegaly and hypofibrinogenemia. Serum levels of ferritin and soluble interleukin-2 receptor (SIL2R) were highly elevated, and the number of natural killer (NK) cells was markedly decreased. An allogeneic stem cell donor was neither found in the family nor in unrelated donor registries; however, an umbilical cord blood (UCB) donor request revealed a 5/6 HLA-matched UCB. After conditioning with busulphan 16 mg/kg body weight (BW), cyclophosphamide 120 mg/kg BW and etoposide (VP-16) 900 mg/m2 the patient received 19.6 x 10(7)UCB nucleated cells/kg BW. White blood count (WBC) reached 1.0 x 10(9)/l on day +45. Chimerism studies showed full and permanent hematopoietic and lymphopoietic engraftment on day +16. However despite full engraftment the patient still experienced two severe relapses of his disease after stem cell transplantation with the highest ferritin level in the range of 10 3967 microg/l (n = 7-142). NK cell function appeared only 6 months after UCB transplantation followed by a decrease of FHL markers and resolution of disease activity. This clinical outcome indicates that unless competent immunologic engraftment after transplantation is established, FHL is capable of relapsing even if complete three-lineage engraftment is achieved.

Hematopoietic progenitor cell levels were monitored in the peripheral blood of ten healthy adults receiving a single dose of recombinant human granulocyte colony-stimulating factor (rhG-CSF). The objective was to determine the time and number of progenitor cells released into the peripheral blood, induced by a single dose of 15 micrograms/kg rhG-CSF administered intravenously. In all cases the absolute number of circulating progenitor cells including granulocyte-macrophage and erythroid lineages increased up to 12-fold (median 9.4-fold) 4 days after treatment. These findings were based on flow cytometric quantification of CD34+ cells and on progenitor assays. The relative distribution of granulocyte/macrophage and erythroid progenitors remained unchanged. rhG-CSF was well tolerated; mild to moderate bone pain was the most common side-effect and was noted in 6 of 10 subjects. Thus a single dose of rhG-CSF is effective in mobilizing progenitor cells into the peripheral blood in healthy adults. If these progenitors are capable of reconstituting bone marrow, peripheral progenitor cell separation following rhG-CSF administration could be a reasonable alternative to conventional bone marrow harvest in healthy adults.

Bone marrow transplantation plays an essential role in the successful treatment of both juvenile and adult chronic myelogenous leukemia. Recently, it has been reported that conditioning with high doses of busulfan can successfully replace total body irradiation (TBI), in patients with acute myelogenous leukemia as well as adult chronic myelogenous leukemia. We report here the case of a 29-month-old boy with juvenile chronic myelogenous leukemia (JCML) transplanted with HLA-identical bone marrow after conditioning with busulfan, etoposide and cyclophosphamide. Successful engraftment was followed by early relapse on day 67. A second HLA-identical transplant was performed following myeloablative treatment with TBI. Engraftment was once again successful and the patient remains free of disease more than 24 months after transplantation. We conclude that busulfan is insufficient in eradicating JCML and that TBI is required prior to transplantation.