Glycogen, poly(3-hydroxybutyrate) and pigment accumulation in three Synechocystis strains when exposed to a stepwise increasing salt stress.

The cyanobacterial genus Synechocystis is of particular interest to science and industry because of its efficient phototrophic metabolism, its accumulation of the polymer poly(3-hydroxybutyrate) (PHB) and its ability to withstand or adapt to adverse growing conditions. One such condition is the increased salinity that can be caused by recycled or brackish water used in cultivation. While overall reduced growth is expected in response to salt stress, other metabolic responses relevant to the efficiency of phototrophic production of biomass or PHB (or both) have been experimentally observed in three Synechocystis strains at stepwise increasing salt concentrations. In response to recent reports on metabolic strategies to increase stress tolerance of heterotrophic and phototrophic bacteria, we focused particularly on the stress-induced response of Synechocystis strains in terms of PHB, glycogen and photoactive pigment dynamics. Of the three strains studied, the strain Synechocystis cf. salina CCALA192 proved to be the most tolerant to salt stress. In addition, this strain showed the highest PHB accumulation. All the three strains accumulated more PHB with increasing salinity, to the point where their photosystems were strongly inhibited and they could no longer produce enough energy to synthesize more PHB.

Pregnancy and pregnancy outcomes after hematopoietic stem cell transplantation in childhood: a cross-sectional survey of the EBMT Pediatric Diseases Working Party.

STUDY QUESTION: What are the characteristics of patients with conceptions transplanted in childhood and adolescence? SUMMARY ANSWER: Insemination and conception after hematopoietic stem cell transplantation (HCT) in childhood or adolescence was possible, even after myeloablative conditioning regimes, although some patients required reproductive medicine support. WHAT IS KNOWN ALREADY: Preparative regimens of HCT are highly gonadotoxic, which leads to gonadal failure and pubertal development disorders. There are few population-based studies assessing the risk of future infertility in children after HCT. STUDY DESIGN, SIZE, DURATION: We conducted a retrospective study to investigate natural or assisted conceptions and their outcomes in patients <18 years old before their first transplantation who received HCT between 1995 and 2016 and were in the European Society for Blood and Marrow Transplantation (EBMT) registry. Adoptions were excluded from the analysis. PARTICIPANTS/MATERIALS, SETTING, METHODS: Detailed information concerning pregnancy occurrences and outcomes were obtained by a separate questionnaire. Quantitative variables were presented as medians with their interquartile range (IQR) or range, and categorical variables were presented as frequencies and percentages. MAIN RESULTS AND THE ROLE OF CHANCE: In total, 62 988 pediatric patients received a first HCT in EBMT centers between 1995 and 2016. Pregnancy was reported in 406 patients in the database. The median age at transplantation was 15.7 (range: 0.7-18) years, and the median age at declared conception was 25.0 (range: 16.3-38.8) years. Details concerning the first pregnancy and pregnancy outcome were obtained from 99 patients (24%) from the returned questionnaires. The median age at delivery or pregnancy interruption of the females was 23.0 (IQR: 20.8-27) years, with a median time after transplant of 10.7 (IQR: 6.6-15.4) years. Compared with the mean age of healthy women at their first child's birth (29 years old), the transplanted women delivered 5 years earlier (mean: 24.3 years). In terms of conception modality, 13/25 (52%) females conditioned with total body irradiation (TBI) and 50/52 (96%) of those conditioned without TBI conceived naturally. All seven male patients who had been conditioned with TBI achieved fatherhood but required assisted fertilization or used their cryopreserved sperm. In the females, 63/70 (90%) of all conceptions resulted in a live birth, 49/63 (84.5%) were at term and 43/46 (93%) had normal birthweight. Cesarean delivery was performed in 9/61 (15%) especially in women who had received a myeloablative regimen. LIMITATIONS, REASONS FOR CAUTION: In the EBMT pediatric dataset, the age at last follow-up or death was <17 years for 75% of the patients, therefore a longer follow-up for all patients would be necessary to calculate the cumulative incidence of conception for patients transplanted during childhood and allow all patients to realize their reproductive willingness/potential. WIDER IMPLICATIONS OF THE FINDINGS: Reproductive health surveillance and fertility preservation counseling are important in younger transplanted patients. Our results showed that there is a window of opportunity to conceive naturally or with reproductive medicine support. STUDY FUNDING/COMPETING INTEREST(S): Funding was provided by the 'Stiftung für krebskranke Kinder Regio Basiliensis', Basel, Switzerland. All authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: N/A.

Total body irradiation is a crucial risk factor for developing secondary carcinomas after allogeneic hematopoietic stem cell transplantation in childhood.

Allogeneic hematopoietic stem cell transplantation (HSCT) has become a standard part of therapy for a variety of malignant and non-malignant disorders. With improved outcomes after HSCT, increasing attention has been drawn to late complications in long-term survivors. The development of secondary malignancies is recognized as one of the most serious complications. We have evaluated data from 426 patients (272 males, 154 females) who underwent allogeneic transplantation at a median age of 7.9 years from 1989 till 2017 and were alive more than one year after transplantation for the occurrence of secondary solid tumors. We have documented the occurrence of secondary solid tumors in 20 patients (4.7%). The median duration of the development of secondary solid cancer from HSCT was 11.7 (range, 5.4-21.5 years). 18 out of 20 patients (90%) had total body irradiation (TBI) 12-14.4 Gy as a part of a conditioning regimen. All but two had transplantation for malignant disease. All patients underwent surgery and/or chemo-radiotherapy. Eighteen are alive, and two died due to the progression of their secondary malignancy. The most frequent solid cancer was thyroid carcinoma (n=9). Cumulative incidence of secondary solid cancer in all groups was 15.2±3.9%, in a group using TBI based regimen 34.7±8.9%, in non-TBI (only chemo) group was 1.5±1.1%. Overall, the cumulative incidence is statistically significantly different between the TBI based and non-TBI (chemo only) group. The incidence and number of complications following allogeneic HSCT in childhood are increasing in time. The early diagnosis of secondary malignancies is one of the key tasks of long-life multidisciplinary post-transplant care.

Early complications in surgery of umbilical and epigastric hernias.

INTRODUCTION: Repairs of umbilical and epigastric hernias are common surgical procedures; the choice of the surgical method generally depends on the size of the hernial sac and fascial defect. METHODS: Data of patients operated on for umbilical or epigastric hernias in our hospital during two years were assessed retrospectively. The study group included 264 patients; 212 had an umbilical hernia and 52 had an epigastric hernia. We assessed epidemiologic and clinical parameters and their correlation with the occurrence of early postoperative complications. We also looked for the recurrence rate, although during only a short follow-up period. RESULTS: In the case of umbilical hernias, early complications occurred in 6.7% (11/165) after surgery with a simple suture and in 4.3% (2/47) with mesh repair, and the recurrence rates were 3% (5/165) and 21.3% (10/47), respectively. The risk of early complications was significantly higher in larger hernias. The recurrence rate increased with older age, an increased size of the hernial sac and fascial defect, and in patients with type 2 diabetes. In epigastric hernias, early complications occurred in 5.3% (1/19) after surgery with a simple suture and in 6.1% (2/33) with mesh repair. Recurrences only occurred in operations with mesh repair, in 9% (3/33). The risk of early complications was significantly higher in type 2 diabetes patients. CONCLUSION: Early complications were slightly more frequent in epigastric hernia repairs with mesh implantation, but this was not the case of umbilical hernias. We recommend mesh implantation in larger and borderline sized hernias to reduce the risk of recurrence.

Diagnosis and severity criteria for sinusoidal obstruction syndrome/veno-occlusive disease in pediatric patients: a new classification from the European society for blood and marrow transplantation.

The advances in hematopoietic cell transplantation (HCT) over the last decade have led to a transplant-related mortality below 15%. Hepatic sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) is a life-threatening complication of HCT that belongs to a group of diseases increasingly identified as transplant-related, systemic endothelial diseases. In most cases, SOS/VOD resolves within weeks; however, severe SOS/VOD results in multi-organ dysfunction/failure with a mortality rate >80%. A timely diagnosis of SOS/VOD is of critical importance, given the availability of therapeutic options with favorable tolerability. Current diagnostic criteria are used for adults and children. However, over the last decade it has become clear that SOS/VOD is significantly different between the age groups in terms of incidence, genetic predisposition, clinical presentation, prevention, treatment and outcome. Improved understanding of SOS/VOD and the availability of effective treatment questions the use of the Baltimore and Seattle criteria for diagnosing SOS/VOD in children. The aim of this position paper is to propose new diagnostic and severity criteria for SOS/VOD in children on behalf of the European Society for Blood and Marrow Transplantation.

Fertility preservation issues in pediatric hematopoietic stem cell transplantation: practical approaches from the consensus of the Pediatric Diseases Working Party of the EBMT and the International BFM Study Group.

Fertility preservation is an urgent challenge in the transplant setting. A panel of transplanters and fertility specialists within the Pediatric Diseases Working Party of the European Society for Blood and Marrow Transplantation (EBMT) and the International BFM Study Group provides specific guidelines. Patients and families should be informed of possible gender- and age-specific cryopreservation strategies that should be tailored according to the underlying disease, clinical condition and previous exposure to chemotherapy. Semen collection should be routinely offered to all postpubertal boys at the diagnosis of any disease requiring therapy that could potentially impair fertility. Testicular tissue collection might be offered to postpubertal boys; nevertheless, its use has been unsuccessful to date. Oocyte collection after hormonal hyperstimulation should be offered to postpubertal girls facing gonadotoxic therapies that could be delayed for the 2 weeks required for the procedure. Ovarian tissue collection could be offered to pre-/post-pubertal girls. Pregnancies have been reported after postpubertal ovarian tissue reimplantation; however, to date, no pregnancy has been reported after the reimplantation of prepubertal ovarian tissue or in vitro maturation of pre-/post-pubertal ovarian tissue. Possible future advances in reproductive medicine could change this scenario. Health authorities should prioritize fertility preservation projects in pediatric transplantation to improve patient care and quality of life.

Next-generation sequencing indicates false-positive MRD results and better predicts prognosis after SCT in patients with childhood ALL.

Minimal residual disease (MRD) monitoring via quantitative PCR (qPCR) detection of Ag receptor gene rearrangements has been the most sensitive method for predicting prognosis and making post-transplant treatment decisions for patients with ALL. Despite the broad clinical usefulness and standardization of this method, we and others have repeatedly reported the possibility of false-positive MRD results caused by massive B-lymphocyte regeneration after stem cell transplantation (SCT). Next-generation sequencing (NGS) enables precise and sensitive detection of multiple Ag receptor rearrangements, thus providing a more specific readout compared to qPCR. We investigated two cohorts of children with ALL who underwent SCT (30 patients and 228 samples). The first cohort consisted of 17 patients who remained in long-term CR after SCT despite having low MRD positivity (<0.01%) at least once during post-SCT monitoring using qPCR. Only one of 27 qPCR-positive samples was confirmed to be positive by NGS. Conversely, 10 of 15 samples with low qPCR-detected MRD positivity from 13 patients who subsequently relapsed were also confirmed to be positive by NGS (P=0.002). These data show that NGS has a better specificity in post-SCT ALL management and indicate that treatment interventions aimed at reverting impending relapse should not be based on qPCR only.

State-of-the-art fertility preservation in children and adolescents undergoing haematopoietic stem cell transplantation: a report on the expert meeting of the Paediatric Diseases Working Party (PDWP) of the European Society for Blood and Marrow Transplantation (EBMT) in Baden, Austria, 29-30 September 2015.

Nowadays, allogeneic haematopoietic stem cell transplantation (allo-HSCT) is a well-established treatment procedure and often the only cure for many patients with malignant and non-malignant diseases. Decrease in short-term complications has substantially contributed to increased survival. Therefore long-term sequelae are reaching the focus of patient care. One of the most important risks of stem cell transplant survivors is infertility. As well as in the field of allo-HSCT also the field of reproductive medicine has achieved substantial advances to offer potential options for fertility preservation in both boys and girls. Access to these procedures as well as their financing differs significantly throughout Europe. As all European children and adolescents should have the same possibility, the Paediatric Diseases Working Party of the European Society for Blood and Marrow Transplantation organised an expert meeting in September 2015. This manuscript describes the recommendations for the diagnosis and pre-emptive procedures that should be offered to all children and adolescents in Europe who have to undergo an allo-HSCT.

Impact of genomic risk factors on survival after haematopoietic stem cell transplantation for patients with acute leukaemia.

The EBMT risk score is an established tool successfully used in the prognosis of survival post-HSCT and is applicable for a range of haematological disorders. One of its main advantages is that score generation involves summation of clinical parameters that are available pretransplant. However, the EBMT risk score is recognized as not being optimal. Previous analyses, involving patients with various diagnoses, have shown that non-HLA gene polymorphisms influence outcome after allogeneic HSCT. This study is novel as it focuses only on patients having acute leukaemia (N = 458) and attempts to demonstrate how non-HLA gene polymorphisms can be added to the EBMT risk score in a Cox regression model to improve prognostic ability for overall survival. The results of the study found that three genetic factors improved EBMT risk score. The presence of MAL (rs8177374) allele T in the patient, absence of glucocorticoid receptor haplotype (consisting of rs6198, rs33389 and rs33388) ACT in the patient and absence of heat-shock protein 70-hom (+2437) (rs2227956) allele C in the patient were associated with decreased survival time. When compared to the EBMT risk score, the scores combining EBMT risk score with the genetic factors had an improved correlation with clinical outcome and better separation of risk groups. A bootstrapping technique, involving repeated testing of a model using multiple validation sets, also revealed that the newly proposed model had improved predictive value when compared to the EBMT risk score alone. Results support the view that non-HLA polymorphisms could be useful for pretransplant clinical assessment and provide evidence that polymorphisms in the recipient genotype may influence incoming donor cells, suppressing the initiation of the graft versus leukaemia effect and reducing survival.

Incidence and severity of crucial late effects after allogeneic HSCT for malignancy under the age of 3 years: TBI is what really matters.

Younger children are considered to be more vulnerable to late effects (LE), which prompted us to study LE in patients after haematopoietic stem cell transplantation (HSCT) for a haematological malignancy before the age of 3. In this multicentre EBMT study, cumulative incidence (CI) and severity of endocrine LE, central nervous system complications and secondary malignancies at 5, 10, 15 and 20 years of follow-up were assessed. Risk factors (RF) like gender, diagnosis, age at and year of HSCT, TBI- or chemo-conditioning and GVHD were analysed. CI of any LE was 0.30, 0.52, 0.66 and 0.72 at 5, 10, 15 and 20 years after HSCT, respectively. In 25% of the patients, LE were severe at a median follow-up of 10.4 years. In multivariate analysis, only TBI was a RF for having any LE and for thyroid dysfunction and growth disturbance. Female gender was a RF for delayed pubertal development. Some more insight could be gained by descriptive analysis regarding the role of TBI and GVHD on the severity of LE. Although only five selected LE have been studied and median follow-up is relatively short, the incidence and severity of these LE are considerable but not different from what has been found in older children and TBI is the main RF.

Treosulfan-based conditioning regimens for allogeneic haematopoietic stem cell transplantation in children with non-malignant diseases.

An increasing number of children with non-malignant diseases can be cured by allogeneic haematopoietic stem cell transplantation (HSCT). Treosulfan (L-treitol-1,4-bis-methanesulfonate) is being used more frequently for conditioning, owing to its' lower toxicity profile compared with conventional myeloablative regimens. A retrospective analysis was performed of children registered in the EBMT database, who received treosulfan before HSCT between January 2005 and 2010, to identify possible dose-related toxicity and determine the incidence of engraftment, treatment-related mortality and overall survival (OS). Results from 316 transplants from 11 different countries are presented. Ninety-five (30%) were under 1 year of age at the time of transplant. OS was 83% and event-free survival was 76%; 3-year OS and event-free survival of infants below 1 year were 79% and 73%, respectively. No association was found with age at transplant, dose of treosulfan given, other agents used in combination with treosulfan, donor type, stem cell source, or second or subsequent transplant. In this report of the largest number of children to date receiving treosulfan for non-malignant diseases, treosulfan is shown to be a safe and effective agent even for those under 1 year of age at the time of transplant. Further prospective studies are needed using precisely defined protocols with pharmacokinetic monitoring and detailed chimerism analysis. In addition, long-term studies will be vital to determine long-term effects, for example, on fertility in comparison with other regimens.

Predicting survival using clinical risk scores and non-HLA immunogenetics.

Previous studies of non-histocompatibility leukocyte antigen (HLA) gene single-nucleotide polymorphisms (SNPs) on subgroups of patients undergoing allogeneic haematopoietic stem cell transplantation (HSCT) revealed an association with transplant outcome. This study further evaluated the association of non-HLA polymorphisms with overall survival in a cohort of 762 HSCT patients using data on 26 polymorphisms in 16 non-HLA genes. When viewed in addition to an already established clinical risk score (EBMT-score), three polymorphisms: rs8177374 in the gene for MyD88-adapter-like (MAL; P=0.026), rs9340799 in the oestrogen receptor gene (ESR; P=0.003) and rs1800795 in interleukin-6 (IL-6; P=0.007) were found to be associated with reduced overall survival, whereas the haplo-genotype (ACC/ACC) in IL-10 was protective (P=0.02). The addition of these non-HLA polymorphisms in a Cox regression model alongside the EBMT-score improved discrimination between risk groups and increased the level of prediction compared with the EBMT-score alone (gain in prediction capability for EBMT-genetic-score 10.8%). Results also demonstrated how changes in clinical practice through time have altered the effects of non-HLA analysis. The study illustrates the significance of non-HLA genotyping prior to HSCT and the importance of further investigation into non-HLA gene polymorphisms in risk prediction.

Post-mortem analysis of Candida albicans breakthrough infection during echinocandin treatment in haematopoietic stem cell transplant recipient.

We present case of a girl deceased due to Candida albicans breakthrough invasive infection during the echinocandin treatment after undergoing allogeneic haematopoietic stem cell transplant for relaps of acute myeloid leukaemia. Candida albicans generally susceptible to all antifungal drugs wasn't considered for potential resistance and conventional blood culture positivity was too late to reveal the resistance to echinocandins. Due to severe organ toxicities (liver, kidneys) she received echinocandin as an antifungal prophylaxis, no change was made for the treatment of Candida albicans infection. Later, the molecular analysis proved the mutation S645P known as being responsible for the echinocandin resistance. The post mortem analysis of fungal burden in autopsy samples showed very high levels of Candida DNA in gut, liver, spleen and kidneys.

Outcome of invasive mechanical ventilation after pediatric allogeneic hematopoietic SCT: results from a prospective, multicenter registry.

Exact data on prognosis of children receiving invasive mechanical ventilation (IMV) after allogeneic hematopoietic SCT (HSCT) is lacking. We therefore started a prospective registry in four European university HSCT centers (Leiden, Paris, Prague and Utrecht) and their pediatric intensive care units (PICUs). The registry started in January 2009. In January 2013, the four centers together had treated a total of 83 admissions with IMV. The case fatality rate in these patients was 52%. Mortality 6 months after PICU discharge was 45%. There were significant differences between centers in the proportion of children who received IMV after HSCT (6-23%, P<0.01), in severity of disease on admission to PICU (predicted mortality 14-37%, P<0.01), in applying noninvasive ventilation before IMV (3-75% of admissions, P<0.01) and in the use of renal replacement therapy (RRT) (8-58% of admissions, P<0.01). Severe impairment in oxygenation, use of RRT and CMV viremia were independent predictors of mortality. Our study shows that mortality in children receiving IMV after HSCT remains high, but has clearly improved compared with older studies. Patient selection and treatment in PICU differed significantly between centers, which underscores the need to standardize and optimize the PICU admission criteria, ventilatory strategies and therapies applied in PICU.

Survey of CMV management in pediatric allogeneic HSCT programs, on behalf of the inborn errors, infectious diseases and pediatric diseases working parties of EBMT.

Human CMV infection is a frequent complication after HSC in children with remarkable morbidity and mortality. Antiviral drugs are relatively efficient but have numerous side effects. They are used as prophylactic, pre-emptive or therapeutic medicines. It is still a matter of debate which option is the best strategy. No uniform procedure has emerged regarding these three options, and new immunologic tools have raised more questions for physicians. To assess the current practice in the management of CMV infection, we sent a questionnaire to the EBMT centers performing hematopoietic SCT (HSCT) in children. Fifty-six out of 196 responded to the questionnaire (28.5%). Quantitative PCR was the most common monitoring tool (44/56). Only 4/56 centers use the pp65 antigenemia alone. All centers used pre-emptive strategy (56/56). 21/56 centers also used prophylactic measures, 13/21 after analysis of donor/receptor serologic status. Ganciclovir was the most common first-line agent for CMV disease (55/56). The most common dose and duration for induction treatment were 5 mg/kg bid (47/55) for 14 days (20/55). There is no uniform procedure for researching resistance strain, antiviral second-line therapy or cell therapy. A harmonization process should enable sound prospective trials to improve prevention, control and cure of CMV disease in children and adolescents.

Allo-SCT using BU, CY and melphalan for children with AML in second CR.

Based on the results from the AML-BFM 98 trial, hematopoietic SCT (HSCT) is recommended for children with AML in second CR only. Here, we retrospectively analyze interphase data of children who underwent HSCT after myeloablative conditioning with BU, CY, and melphalan (BuCyMel) for AML in second remission (CR2) between 1998 and 2009. Out of 152 children, transplant data were available on 109 individuals. Sixty out of 109 children (55%) received BuCyMel. Median age at HSCT was 12.2 years (range 3.0; 18.3). GVHD prophylaxis mostly consisted of CsA and short term MTX with or without antithymocyte globulin. Matched-sibling donors were used for 6/60 analyzed recipients, the remainder either received grafts from matched unrelated (30/60) or mismatched donors. OS after 5 years was 62% (s.e. 6%), relapse incidence 35% (18/60 children) and treatment-related mortality accounted for 12% (7/60) of fatal events. In conclusion, even taking into account possible selection bias in this retrospective analysis, HSCT in CR2 using BuCyMel resulted in a respectable OS. Based on this data the prospective, controlled and centrally monitored AML SCT-BFM 2007 trial has started to recruit patients in January 2010 aiming to generate valid outcome data for further strategy decisions.

Expansion of T helper type 17 lymphocytes in patients with chronic granulomatous disease.

Hyper-immunoglobulin (Ig)E syndrome (HIES) is a primary immunodeficiency associated with mutations in STAT3 resulting in impaired development of T helper type 17 (Th17) lymphocytes. HIES patients with a reduced frequency of Th17 cells present with infections caused by Staphylococcus aureus and/or Candida strains. The same spectrum of pathogens is present in patients with chronic granulomatous disease (CGD).We analysed the characteristics of the Th17 compartment in HIES and CGD. HIES patients showed very low numbers of Th17 cells. By contrast, the frequency of Th17 cells and production of Th17-derived cytokines was significantly higher among CGD patients when compared to both control samples and HIES. Naive CD4(+) cells in CGD patients had a normal capacity to differentiate into IL-17-producing cells and the numbers of Th17 cells in the CGD patients normalized following successful bone marrow transplantation. Our findings complement recent data on the importance of Th17 cells for elimination of infections with C. albicans and S. aureus.

Hematopoietic stem cell transplantation for advanced myelodysplastic syndrome in children: results of the EWOG-MDS 98 study.

We report on the outcome of children with advanced primary myelodysplastic syndrome (MDS) transplanted from an HLA-matched sibling (MSD) or an unrelated donor (UD) following a preparative regimen with busulfan, cyclophosphamide and melphalan. Ninety-seven patients with refractory anemia with excess blasts (RAEB, n=53), RAEB in transformation (RAEB-T, n=29) and myelodysplasia-related acute myeloid leukemia (MDR-AML, n=15) enrolled in the European Working Group of MDS in Childhood (EWOG-MDS) 98 study and given hematopoietic stem cell transplantation (HSCT) were analyzed. Median age at HSCT was 11.1 years (range 1.4-19.0). Thirty-nine children were transplanted from an MSD, whereas 58 were given the allograft from a UD (n=57) or alternative family donor (n=1). Stem cell source was bone marrow (n=69) or peripheral blood (n=28). With a median follow-up of 3.9 years (range 0.1-10.9), the 5-year probability of overall survival is 63%, while the 5-year cumulative incidence of transplantation-related mortality (TRM) and relapse is 21% each. Age at HSCT greater than 12 years, interval between diagnosis and HSCT longer than 4 months, and occurrence of acute or extensive chronic graft-versus-host disease were associated with increased TRM. The risk of relapse increased with more advanced disease. This study indicates that HSCT following a myeloablative preparative regimen offers a high probability of survival for children with advanced MDS.

Signature profiles of CMV-specific T-cells in patients with CMV reactivation after hematopoietic SCT.

Depletion of cellular immunity as a consequence of conditioning before allogeneic hematopoietic SCT (HSCT) frequently results in CMV reactivation, which may in turn lead to life-threatening infections and require timely antiviral treatment. We have investigated the functional signatures of CMV-specific CD4+ and CD8+ T-cells in 191 samples from 118 individuals. We compared healthy donors with both patients with high and undetectable viral loads, and those who controlled and did not control their CMV reactivations. Polychromatic flow-cytometric measurements of CD154 (CD40L), intracellular cytokines (IFNγ, IL2) and a degranulation marker (CD107a) allowed us to assess the functional status of various T-cells simultaneously. We found that dual IFNγ/IL2-producing CD8+ T-cells were present in patients controlling their CMV reactivations but absent from non-controllers. CD8+ T-cells that produce only IFNγ were the most abundant subtype, but they most likely represent non-protective memory cells. Distinct functional signatures were examined by hierarchical clustering, and this revealed that, unlike polyfunctional CD8+ T-cells, CD8+ T-cells that produce IFNγ alone were not functioning in concert with other subsets. In conclusion, our study revealed functional signatures that may be useful for immune monitoring, and it could change the interpretation of previous studies that assessed only IFNγ.