Minna Koskenvuo

BK polyomavirus-associated hemorrhagic cystitis among pediatric allogeneic bone marrow transplant recipients: Treatment response and evidence for nosocomial transmission

BACKGROUND BK polyomavirus-associated hemorrhagic cystitis (BK-PyVHC) is a significant complication of allogenic hematopoietic stem cell transplantation (HSCT), but risk factors and treatment are currently unresolved. BK-PyVHC typically presents with clinical cystitis, macrohematuria, and increasing urine and blood BKV loads. OBJECTIVES Characterization of children undergoing allogeneic HSCT with BK-PyVHC and their clinical and antibody response to cidofovir treatment. STUDY DESIGN By prospective screening of urine and plasma in 50 pediatric allogenic HSCT performed between 2008 and 2010, we identified 6 (12%) children with BK-PyVHC. Cidofovir was administered intravenously to 5 patients and intravesically to 4 patients (3 double treatments). RESULTS Decreasing BKV viremia of>2log(10)copies/mL and clinical resolution was seen in 4 patients over 5-12 weeks. Responses occurred only in patients mounting BKV-specific IgM and IgG responses. Epidemic curve plots, BKV genotyping and contact tracing provided evidence of transmission between 2 BKV-seronegative patients, but ruled out transmission among the remaining four patients CONCLUSIONS The data suggest that BK-PyVHC may be the result of nosocomial transmission in children with low/undetectable BKV antibodies and raises urgent questions about appropriate infection control measures and the role of cidofovir.

Hematopoietic stem cell transplantation rescues the hematological, immunological and vascular phenotype in DADA2

Deficiency of adenosine deaminase 2 (DADA2) is caused by biallelic deleterious mutations in CECR1 DADA2 results in variable autoinflammation and vasculopathy (recurrent fevers, livedo reticularis, polyarteritis nodosa, lacunar ischemic strokes, and intracranial hemorrhages), immunodeficiency and bone marrow failure. Tumor necrosis factor-α blockade is the treatment of choice for the autoinflammation and vascular manifestations. Hematopoietic stem cell transplantation (HSCT) represents a potential definitive treatment. We present a cohort of 14 patients from 6 countries who received HSCT for DADA2. Indication for HSCT was bone marrow dysfunction or immunodeficiency. Six of 14 patients had vasculitis pre-HSCT. The median age at HSCT was 7.5 years. Conditioning regimens were myeloablative (9) and reduced intensity (5). Donors were HLA-matched sibling (n = 1), HLA-matched unrelated (n = 9), HLA-mismatched unrelated (n = 3), and HLA haploidentical sibling (n = 1). All patients are alive and well with no new vascular events and resolution of hematological and immunological phenotype at a median follow-up of 18 months (range, 5 months to 13 years). Plasma ADA2 enzyme activity normalized in those tested post-HSCT (7/7), as early as day +14 (myeloid engraftment). Post-HSCT hematological autoimmunity (cytopenias) was reported in 4 patients, acute graft-versus-host disease grade 1 in 2, grade 2 in 3, and grade 3-4 in 1, and moderate chronic graft-versus-host disease in 1 patient. In conclusion, in 14 patients, HSCT was an effective and definitive treatment of DADA2.

Effect of age and body weight on toxicity and survival in pediatric acute myeloid leukemia: results from NOPHO-AML 2004

Treatment for pediatric acute myeloid leukemia is very toxic and the association between outcome and age and Body Mass Index is unclear. We investigated effect of age and Body Mass Index on toxicity and survival in pediatric acute myeloid leukemia. We studied all patients who completed first induction course of NOPHO-AML 2004 (n=318). Toxicity following induction and consolidation courses (n=6) was analyzed. The probabilities of toxicity and death were determined using time-to-event analyses with Cox multivariate proportional hazard regression for comparative analyses. Age 10–17 years was associated with sepsis with hypotension [hazard ratio 2.3 (95% confidence interval 1.1–4.6)]. Being overweight (>1 standard deviation) was associated with requiring supplemental oxygen [1.9 (1.0–3.5)]. The 5-year event-free and overall survival were 47% and 71%. Children aged 10–17 years showed a trend for inferior 5-year overall survival compared to children aged 2–9 (64% vs. 76%; P=0.07). Infants showed a trend for superior 5-year event-free survival (66% vs. 43%; P=0.06). Overweight children aged 10–17 years showed a trend for superior survival [5-year event-free survival 59% vs. 40% (P=0.09) and 5-year overall survival 78% vs. 56% (P=0.06)] compared to healthy weight children aged 10–17 years. In conclusion, children aged 10–17 years and overweight children had a higher risk of grade 3–4 toxicity. Children aged 10–17 years showed inferior survival, but, unexpectedly, in this age group overweight children tended to have increased survival. This suggests different pharmacokinetics of chemotherapeutic drugs in adolescents and warrants further studies.

Diffuse gastrointestinal bleeding and BK polyomavirus replication in a pediatric allogeneic haematopoietic stem cell transplant patient

Patients undergoing haematopoietic stem cell transplantation (HSCT) are at high risk of severe gastrointestinal bleeding caused by infections, graft versus host disease, and disturbances in haemostasis. BK polyomavirus (BKPyV) is known to cause hemorrhagic cystitis, but there is also evidence of BKV shedding in stool and its association with gastrointestinal disease. We report putative association of BKPyV replication with high plasma viral loads in a pediatric HSCT patient developing hemorrhagic cystitis and severe gastrointestinal bleeding necessitating intensive care. The observation was based on chart review and analysis of BKPyV DNA loads in plasma and urine as well as retrospective BKPyV-specific IgM and IgG measurements in weekly samples until three months post-transplant. The gastrointestinal bleeding was observed after a >100-fold increase in the plasma BKPyV loads and the start of hemorrhagic cystitis. The BKPyV-specific antibody response indicated past infection prior to transplantation, but increasing IgG titers were seen following BKPyV replication. The gastrointestinal biopsies were taken at a late stage of the episode and were no longer informative of BK polyomavirus involvement. In conclusion, gastrointestinal complications with bleeding are a significant problem after allogeneic HSCT to which viral infections including BKPyV may contribute.

Viremic co-infections in children with allogeneic haematopoietic stem cell transplantation are predominated by human polyomaviruses

Abstract Background: Viral infections remain the cause of key complications following haematopoietic stem cell transplantation (HSCT). The impact of multiple, concurrent viral reactivations/infections remains to be delineated. Methods: The clinical correlates of single or multiple viremic infections following HSCT and especially the occurrence of respiratory viruses in the bloodstream were investigated. We retrospectively searched for 23 viruses in a total of 184 sera from 53 paediatric patients. The time-points of interest were pre-HSCT, one, two and three months post-HSCT, and at discharge or death. The viruses were analyzed by quantitative or qualitative PCR. Results: Of the 53 patients, 13 (25%) had viraemias by multiple viruses and 27 (51%) by a single virus. Thirteen patients (25%) had no viruses detected by PCR during the study period. In the children with viremic co-infections, polyomaviruses predominated over herpes viruses. Nearly half the patients, 24/53 (45%) had a polyomavirus in their serum at one or more time-points. At 12/15 time-points and in 11/13 patients with co-infections polyomaviruses were involved, compared with 6/15 time-points and 6/13 patients for cytomegalovirus. Acute graft-versus-host disease (GvHD) and steroid use were significant risk factors for the viraemias caused by more than one virus. Conclusions: Viral co-detection is a common finding in children undergoing HSCT. With large-scale viral screening also viruses other than CMV could be found as potential pathogens. In this study, BKPyV predominated over CMV as a contributor in viraemias caused by multiple viruses in children receiving HSCT.

Immunological Reconstitution in Children After Completing Conventional Chemotherapy of Acute Lymphoblastic Leukemia is Marked by Impaired B-cell Compartment

Humoral and cellular immunity were studied in 28 children completing conventional treatment of standard‐risk (SR) or intermediate‐risk (IR) acute lymphoblastic leukemia (ALL). Both naïve and memory B cells were most severely affected and showed slow recovery during the 2‐year follow‐up, while the T‐cell compartment showed only minor changes. Immunoglobulins and IgG subclasses, components, and antibodies against vaccine‐preventable diseases were not significantly affected. In conclusion, immune recovery after conventional chemotherapy for SR and IR ALL is marked by B‐cell depletion, but otherwise did not show any severe deficiencies in lymphocyte function.

Diagnostics of rare disorders : whole-exome sequencing deciphering locus heterogeneity in telomere biology disorders

BackgroundThe telomere biology disorders (TBDs) include a range of multisystem diseases characterized by mucocutaneous symptoms and bone marrow failure. In dyskeratosis congenita (DKC), the clinical features of TBDs stem from the depletion of crucial stem cell populations in highly proliferative tissues, resulting from abnormal telomerase function. Due to the wide spectrum of clinical presentations and lack of a conclusive laboratory test it may be challenging to reach a clinical diagnosis, especially if patients lack the pathognomonic clinical features of TBDs.MethodsClinical sequencing was performed on a cohort of patients presenting with variable immune phenotypes lacking molecular diagnoses. Hypothesis-free whole-exome sequencing (WES) was selected in the absence of compelling diagnostic hints in patients with variable immunological and haematological conditions.ResultsIn four patients belonging to three families, we have detected five novel variants in known TBD-causing genes (DKC1, TERT and RTEL1). In addition to the molecular findings, they all presented shortened blood cell telomeres. These findings are consistent with the displayed TBD phenotypes, addressing towards the molecular diagnosis and subsequent clinical follow-up of the patients.ConclusionsOur results strongly support the utility of WES-based approaches for routine genetic diagnostics of TBD patients with heterogeneous or atypical clinical presentation who otherwise might remain undiagnosed.

Polyomaviruses BK, JC, KI, WU, MC, and TS in children with allogeneic hematopoietic stem cell transplantation.

Timely and reliable detection of viruses is of key importance in early diagnosis of infection(s) following allogeneic HSCT. Among the immunocompetent, infections with BKPyV and JCPyV are mostly subclinical, while post‐HSCT, the former may cause HC and the latter PML. The epidemiology and clinical impact of the newly identified KIPyV, WUPyV, MCPyV, and TSPyV in this context remain to be defined. To assess the incidence and clinical impact of BKPyV, JCPyV, KIPyV, WUPyV, MCPyV, and TSPyV infections, we performed longitudinal molecular surveillance for DNAemias of these HPyVs among 53 pediatric HSCT recipients. Surveillance pre‐HSCT and for three months post‐HSCT revealed BKPyV DNAemia in 20 (38%) patients. Our data demonstrate frequent BKPyV DNAemia among pediatric patients with HSCT and the confinement of clinical symptoms to high copy numbers alone. MCPyV and JCPyV viremias occurred at low and TSPyV viremia at very low prevalences. KIPyV or WUPyV viremias were not demonstrable in this group of immunocompromised patients.

Haematopoietic Stem Cell Transplantation in Children Shifts the Coagulation System towards a Pro-Coagulant State

Coagulation system is disturbed by several mechanisms after allogeneic haematopoietic stem cell transplantation (HSCT). We evaluated the effect of HSCT on coagulation system by various conventional and investigational methods in 30 children and adolescents who received HSCT due to haematological malignancies. Pro-thrombin fragment 1 + 2, a specific measure of thrombin generation, and von Willebrand factor, a measure of endothelial activation, increased after conditioning treatment, and remained elevated until 3 months after HSCT (p < 0.05 for all comparisons to pre-conditioning treatment). D-dimer, a measure of fibrin turnover, was elevated from the second week onwards until 4 weeks after HSCT (p < 0.05). Endogenous thrombin potential was increased after conditioning, and at 2 weeks after HSCT (p < 0.05). Furthermore, the activities of acute phase reactants fibrinogen and coagulation factor VIII were increased (p < 0.05 for all comparisons to pre-conditioning treatment) from the first week onwards up to 3 weeks and 3 months after HSCT, respectively. Taken together, paediatric patients receiving HSCT demonstrate distinct and prolonged variations in the coagulation system towards a pro-coagulant state. This shift is of importance when estimating the risk of haemostatic and thrombotic complications in these children.

Associations between neutrophil recovery time, infections and relapse in pediatric acute myeloid leukemia

Children with acute myeloid leukemia (AML) treated similarly show different toxicity and leukemic responses. We investigated associations between neutrophil recovery time after the first induction course, infection and relapse in children treated according to NOPHO‐AML 2004 and DB AML‐01.