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The impact of persistent mixed chimerism (MC) after haematopoietic stem cell transplantation (HSCT) remains unclarified. We investigated the incidence of MC in peripheral blood beyond day +50 after HSCT and its impact on rejection, chronic graft-versus-host disease (c-GvHD) and relapse in 161 children receiving allogeneic HSCT for haematological malignancies. The 1-year incidence of late MC was 26%. Spontaneous conversion to complete donor chimerism (CC) occurred in 43% of patients as compared to 62% after donor lymphocyte infusions. No graft rejection occurred. The 1-year incidence of c-GvHD was 20 ± 7% for MC, and 18 ± 4% for CC patients (P = 0·734). The 3-year cumulative incidence of relapse (CIR) according to chimerism status at days +50 and +100 was 22 ± 4% for CC patients vs. 22 ± 8% for MC patients (day +50; P = 0·935) and 21 ± 4% vs. 20 ± 7% (day +100; P = 0·907). Three-year CIRs in patients with persistent MC and patients with CC/limited MC were comparable (8 ± 7% vs. 19 ± 4%; P = 0·960). HSCT for acute leukaemia or myelodysplastic syndrome as secondary malignancies (hazard ratio (HR) 4·7; P = 0·008), for AML (HR 3·0; P = 0·02) and from mismatched donors (HR 3·1; P = 0·03) were independent factors associated with relapse. Our data suggest that late MC neither protects from c-GvHD nor does it reliably predict impending disease relapse., (© 2016 John Wiley & Sons Ltd.)

During periods of immunosuppression, such as postallogeneic stem cell transplantation (SCT), patients are at significant risk for severe viral infections. Human adenovirus (HAdV) infection is a serious complication post-SCT, especially in children. Virus-specific T cells are essential for the clearance of HAdV, as antiviral chemotherapy has revealed limited success. We present feasibility data for a new treatment option using virus-specific donor T cells for adoptive transfer of immunity to patients with HAdV-infection/reactivation. Virus-specific donor T cells were isolated and infused into nine children with systemic HAdV infection after SCT. Isolation was based on gamma-interferon (IFN-gamma) secretion after short in vitro stimulation with viral antigen, resulting in a combination of CD4(+) and CD8(+) T cells. 1.2-50 x 10(3)/kg T cells were infused for adoptive transfer. Isolated cells showed high specificity and markedly reduced alloreactivity in vitro. Adoptive transfer of HAdV-specific immunity was successful in five of six evaluable patients, documented by a dose-independent and sustained in vivo expansion of HAdV-specific T cells, associated with a durable clearance/decrease of viral copies. T-cell infusion was well tolerated in all nine patients, except one case with graft-versus-host disease II of the skin. In conclusion, induction of a specific T-cell response through adoptive transfer was feasible and effective. When performed early in the course of infection, adoptive T-cell transfer may protect from HAdV-related complications.

Philadelphia chromosome-positive (Ph+) acute leukaemia usually shows lymphoblastic morphology and a B-precursor phenotype. The bone marrow aspirate of a 9-year-old boy showed a L3 blast cell morphology in 90% of cells; immunophenotyping revealed a mature B-blast population. The translocation t(9;22) (q34;q11) was seen in 45 out of 50 metaphases, and expression of the corresponding bcr1/abl fusion transcripts, but no IgH/myc co-localization or splitting of c-myc, was demonstrated. Chemotherapy according to the Berlin-Frankfurt-Munster non-Hodgkin's lymphoma (NHL-BFM 95) protocol with maintenance according to the BFM acute lymphoblastic leukaemia (ALL-BFM 90) protocol resulted in continuing complete remission of 54 months. The occurrence of Ph+ Burkitt's leukaemia might reflect multiple-step cancer development.

Approximately 31 patients with chronic myelogenous leukaemia (CML) are documented in the literature who survived more than 10 years after diagnosis. We present a CML-patient whose survival of 27 years is probably the longest reported so far. The analysis of the course of disease in these patients revealed that the duration of unmaintained first remission after chemotherapy is of high prognostic significance. In 17 of 24 evaluable patients the remission lasted more than 1 year and in another five at least 6 months (mean 73.8 months, range 0-240 months). In most patients busulfan was used as initial therapy. There was no correlation between the amount of drug given and the duration of remission or survival. Other parameters such as sex, age, initial leucocyte counts, differential count, haemoglobin, platelet count or spleen size seemed to have no prognostic relevance. While approximately 25% of CML patients with typical duration of survival exhibit a Ph1 chromosome mosaicism only, this finding was present in nearly half of the long-term survivers.