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Therapy of children with post‐transplantation lymphoproliferative disorder (PTLD) after hematopoietic stem cell (HSCT) and solid organ transplantation (SOT) can be challenging. In this retrospective study, we investigated PD‐L1 and PD1 expression in all PTLD categories of childhood and adolescence to see whether checkpoint inhibition with PD‐L1/PD1 inhibitors may serve as a therapy option. We included 21 patients aged 19 years or younger (at date of transplant) with PTLD following SOT or HSCT having adequate tumor samples available (n = 29). Using immunohistochemistry, we evaluated PD‐L1/PD1 expression on both tumor cells and cells of the microenvironment in all samples. Availability of consecutively matched tumor samples during 6 of 21 patients' disease courses also allowed an intra‐individual assessment of PD‐L1/PD1 expression. We observed lower PD‐L1 and higher PD1 expression in non‐destructive lesions, and higher PD‐L1 and lower PD1 expression in polymorphic and, in particular, in monomorphic PTLD, mostly diffuse large B‐cell lymphomas (DLBCL, n = 10/21). The amount of PD‐L1‐ and PD1‐positive cells changed in the opposite way in sequential biopsies of the same individual correlating well with the PTLD category. This is the first comprehensive pediatric study assessing PD‐L1 and PD1 expression on tumor cells and in the microenvironment of PTLD including not only monomorphic, but also non‐destructive early lesions. PD‐L1 expression of the tumor cells inversely correlated with PD1 expression in surrounding tissues, with the highest expression in DLBCL. Since PTLD can be therapeutically challenging, our results indicate a potential efficacy of checkpoint inhibitors if standard immune‐ and/or chemotherapy fail or are impossible. We therefore recommend routine staining of PD‐L1 and PD1 in all PTLD categories.

Background and Objectives Our post-thaw cell recovery rates differed substantially in interlaboratory comparisons of identical samples, potentially due to different temperatures during cell staining. Materials and Methods Viable CD34+ cells and leucocyte (WBC) subtypes were quantified by multiparameter single-platform flow cytometry in leucapheresis products collected from 30 adult lymphoma and myeloma patients, and from 10 paediatric patients. After thawing, cells were prepared for analysis within 30 min between thawing and acquisition, at either 4°C or at room temperature. Results For cell products cryopreserved in conventional freezing medium (10% final DMSO), viable cell recovery was clearly lower after staining at 4°C than at RT. Of all WBC subtypes analysed, CD4+ T cells showed the lowest median recovery of 4% (4°C) vs. 25% (RT), followed by CD3, CD34 and CD8 cells. The recovery was highest for CD3γδ cells with 44% (4°C) vs. 71% (RT). In the 10 samples cryopreserved in synthetic freezing medium (5% final DMSO), median recovery rates were 89% for viable CD34 (both at 4°C and RT) and 79% (4°C) vs 68% (RT) for WBC. Conclusions The post-thaw environment and, potentially, the cryoprotectant impact the outcome of cell enumeration, and results from the analysis tube may not be representative of the cells infused into a patient.

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.

Rothia mucilaginosa is part of the oral and upper respiratory tract flora. Usually, this gram-positive coccus is not pathogenic; however, in the setting of immunosuppressed hosts, it can cause life-threatening infections as an opportunistic pathogen. Among a cohort of 1511 hematologic-oncologic patients at a pediatric tertiary care cancer center, we identified five cancer patients (0.35%) within a period of 10 years having a proven Rothia mucilaginosa bacteremia (1 culture positive: n = 3/5; > 1 culture positive: n = 2/5). With prompt and adequate antibiotic treatment, infection resolved rapidly before recovery of neutrophils and without any sequelae, suggesting that Rothia mucilaginosa bacteremia without organ involvement is not exceptionally problematic in pediatric cancer patients.

Erythrocyte-exchange (EEX) has proven to be a very useful tool in sickle-cell disease (SCD) patients either during acute painful crisis unresponsive to hydration and/or analgesia or as a prophylactic treatment in high risk patients in those who do not tolerate hydroxyurea (HU), with the aim of lowering HbS levels. EEX may be performed either by using continuous- or discontinuous flow devices, the former being of choice in children or in low-weight patients. Thus, a low extracorporeal blood volume (EBV) could allow for a better and safer procedure management. In this study we compared EEX procedure performed with the recently released OPTIA device with EEX procedures performed using the COBE Spectra device (EBV 185 vs 270 mL, respectively). Twenty-one EEX (4 as emergency treatment) were performed in 12 patients with the Spectra device and 25 (9 as emergency treatment) in 15 patients with the OPTIA device. All the procedures were well tolerated and uneventful. We did not observe significant differences between the two devices as to pre- and post-EEX parameters, namely in target hematocrit and in HbS reduction. Noteworthy, due to the lowest EBV allowed by the OPTIA device, an EEX procedure performed in a 13 Kg- child did not require a preliminary priming of the circuit. In conclusion, the OPTIA device proved to be as effective as the Spectra device in treating SCD patients either during sickling crisis or as prophylactic therapy. The OPTIA device can be safely used in the pediatric setting since it allows a lower EBV.

Background Approximately 30% of childhood acute lymphoblastic leukemia (ALL) cases are high hyperdiploid (HD). Despite their low relative recurrence risk, this group accounts for the overall largest relapse proportion. Procedure To evaluate potential risk factors in our population-based cohort of patients with HD ALL enrolled in four Austrian ALL-BFM (Berlin-Frankfurt-Munster) studies from 1986 to 2010 (n = 210), we reviewed the clinical, laboratory, and cytogenetic data of the respective cases in relation to their outcome. Results The 5-year event-free (EFS) and overall survival (OS) of the entire group was 83.1 ± 2.7% and 92.0 ± 1.9%, respectively. Univariate analysis revealed that trisomy 17 was significantly associated with a better EFS and OS, whereas trisomy 10 and a modal chromosome number (MCN) > 53 chromosomes were significantly associated with a better OS. Except for the latter, findings remained valid in multivariate analysis. Conclusions In line with previous studies, our retrospective analysis shows that MCN and specific trisomies are relevant prognostic indicators in an ALL-BFM cohort of patients with HD ALL. However, considering the current dominant role of minimal residual disease monitoring for prognostic stratification in ALL, including this particular subgroup, it is unlikely that this information is compelling enough to be utilized for refined risk classification in future ALL-BFM treatment protocols.

Die Titelverbindungen 4 werden durch N-7-Dealkylierung der 2-Furanylmethyl-, 2-Thiophenylmethyl-, oder 1-Phenylethyl-Gruppe aus den Derivaten 2a – g und 10a – j mit Polyphosphoraure erhalten. Im Gegensatz zur 2-Furanylmethyl-Gruppe lassen sich die 2-Thiophenylmethyl- und 1-Phenylethyl-Gruppen unabhangig von der Substitution am Heterobicyclus entfernen. Synthesis of 7-Unsubstituted 7H-Pyrrolo[2,3-d]pyrimidines The title compounds 4 are obtained by N-7 dealkylation of the 2-furanylmethyl, 2-thio-phenylmethyl, or 1-phenylethyl group from 2a – g and 10 – j with polyphosphoric acid. In contrast to the 2-furanylmethyl group the 2-thiophenylmethyl and 1-phenylethyl group can be removed independently of the substitution of the heterobicycle.