Identification and Characterization of a Nontypeable Haemophilus Influenzae Putative Toxin-Antitoxin Locus

Background: Certain strains of an obligate parasite of the human upper respiratory tract, nontypeable Haemophilus influenzae (NTHi), can cause invasive diseases such as septicemia and meningitis, as well as chronic mucosal infections such as otitis media. To do this, the organism must invade and survive within both epithelial and endothelial cells. We have identified a facilitator of NT(Hi) survival inside human cells, virulence-associated protein D (vapDHi, encoded by gene H10450). Both vapDHi and a flanking gene, H10451, exhibit the genetic and physical characteristics of a toxin/antitoxin ( TA) locus, with VapDHi serving as the toxin moiety and H10451 as the antitoxin. We propose the name VapXHi for the H10451 antitoxin protein. Originally identified on plasmids, TA loci have been found on the chromosomes of a number of bacterial pathogens, and have been implicated in the control of translation during stressful conditions. Translation arrest would enhance survival within human cells and facilitate persistent or chronic mucosal infections. Results: Isogenic mutants in vapDHi were attenuated for survival inside human respiratory epithelial cells (NCI-H292) and human brain microvascular endothelial cells (HBMEC), the in vitro models of mucosal infection and the blood-brain barrier, respectively. Transcomplementation with a vapDHi allele restored wild-type NTHi survival within both cell lines. A PCR survey of 59 H. influenzae strains isolated from various anatomical sites determined the presence of a vapDHi allele in 100% of strains. Two isoforms of the gene were identified in this population; one that was 91 residues in length, and another that was truncated to 45 amino acids due to an in-frame deletion. The truncated allele failed to transcomplement the NTHi vapDHi survival defect in HBMEC. Subunits of full-length VapDHi homodimerized, but subunits of the truncated protein did not. However, truncated protein subunits did interact with full-length subunits, and this interaction resulted in a dominant-negative phenotype. Although Escherichia coli does not contain a homologue of either vapDHi or vapXHi, overexpression of the VapDHi toxin in trans resulted in E. coli cell growth arrest. This arrest could be rescued by providing the VapXHi antitoxin on a compatible plasmid. Conclusion: We conclude that vapDHi and vapXHi may constitute a H. influenzae TA locus that functions to enhance NTHi survival within human epithelial and endothelial cells

Erhöhte basale Serumtryptasekonzentration oder Mastozytose als Risikofaktor der Hymenopterengiftallergie Leitlinie der Deutschen Gesellschaft für Allergologie und Klinische Immunologie (DGAKI) (AWMF-Leitlinie 061/018)

Hymenopterengift-allergische Patienten mit Mastzellerkrankung, das heißt Mastozytose und/oder erhöhtem basalen Serumtryptasespiegel, haben ein hohes Risiko schwerer, lebensbedrohender Stichreaktionen. Bei ihnen ist eine spezifische Immuntherapie mit Bienen- oder Wespengift besonders dringlich. Die Wirksamkeit der Hyposensibilisierung ist bei diesen Patienten grundsätzlich nicht eingeschränkt. Allerdings benötigen sie häufiger eine höhere Erhaltungsdosis als die Standarddosis von 100μg, so dass eine Therapiekontrolle durch Stichprovokation besonders wichtig ist. Bei Bienengifthyposensibilisierung, die weniger wirksam ist als Wespengifthyposensibilisierung, wird von vornherein eine Erhaltungsdosis von 200μg gegeben. Weiter ist bei Mastzellerkrankungen eine lebenslange Fortführung der spezifischen Immuntherapie indiziert. Um das Vorliegen einer Mastzellerkrankung zu erkennen, sind vor allem eine sorgfältige Inspektion der Haut hinsichtlich einer kutanen Mastozytose sowie die Messung der basalen Serumtryptasekonzentration erforderlich. Besteht eine Mastzellerkrankung, so sind weitere Untersuchungen nötig, um gegebenenfalls eine systemische Mastozytose zu erfasse

Sequential anti-cytomegalovirus response monitoring may allow prediction of cytomegalovirus reactivation after allogeneic stem cell transplantation

Background: Reconstitution of cytomegalovirus-specific CD3+CD8+ T cells (CMV-CTLs) after allogeneic hematopoietic stem cell transplantation (HSCT) is necessary to bring cytomegalovirus (CMV) reactivation under control. However, the parameters determining protective CMV-CTL reconstitution remain unclear to date. Design and Methods: In a prospective tri-center study, CMV-CTL reconstitution was analyzed in the peripheral blood from 278 patients during the year following HSCT using 7 commercially available tetrameric HLA-CMV epitope complexes. All patients included could be monitored with at least CMV-specific tetramer. Results: CMV-CTL reconstitution was detected in 198 patients (71%) after allogeneic HSCT. Most importantly, reconstitution with 1 CMV-CTL per µl blood between day +50 and day +75 post-HSCT discriminated between patients with and without CMV reactivation in the R+/D+ patient group, independent of the CMV-epitope recognized. In addition, CMV-CTLs expanded more daramtaically in patients experiencing only one CMV-reactivation than those without or those with multiple CMV reactivations. Monitoring using at least 2 tetramers was possible in 63% (n = 176) of the patients. The combinations of particular HLA molecules influenced the numbers of CMV-CTLs detected. The highest CMV-CTL count obtained for an individual tetramer also changed over time in 11% of these patients (n = 19) resulting in higher levels of HLA-B*0801 (IE-1) recognizing CMV-CTLs in 14 patients. Conclusions: Our results indicate that 1 CMV-CTL per µl blood between day +50 to +75 marks the beginning of an immune response against CMV in the R+/D+ group. Detection of CMV-CTL expansion thereafter indicates successful resolution of the CMV reactivation. Thus, sequential monitoring of CMV-CTL reconstitution can be used to predict patients at risk for recurrent CMV reactivation

Failure of Interferon γ to Induce the Anti-Inflammatory Interleukin 18 Binding Protein in Familial Hemophagocytosis

Background: Familial hemophagocytosis (FHL) is a rare disease associated with defects in proteins involved in CD8+ T-cell cytotoxicity. Hyperactivation of immune cells results in a perilous, Th1-driven cytokine storm. We set out to explore the regulation of cytokines in an FHL patient who was clinically stable on low-dose immunosuppressive therapy after bone marrow transplantation over a six-month period. During this period, chimerism analyses showed that the fraction of host cells was between 1 and 10%. Both parents of the patient as well as healthy volunteers were studied for comparison. Methods/Principal Findings: Using ELISA, quantitative real-time PCR, and clinical laboratory methods, we investigated constitutive and inducible cytokines, polymorphisms, and clinical parameters in whole blood and whole blood cultures. Although routine laboratory tests were within the normal range, the chemokines IP-10 and IL-8 as well as the cytokine IL-27p28 were increased up to 10-fold under constitutive and stimulated conditions compared to healthy controls. Moreover, high levels of IFNgamma and TNFalpha were produced upon stimulation. Unexpectedly, IFNgamma induction of IL-18 binding protein (IL-18BP) was markedly reduced (1.6-fold vs 5-fold in controls). The patient's mother featured intermediately increased cytokine levels, whereas levels in the father were similar to those in the controls. Conclusions/Significance: Since IL-18 plays a major role in perpetuating hemophagocytosis, the failure of IFNgamma to induce IL-18BP may constitute a fundamental pathogenetic mechanism. Furthermore, increased production of IL-8 and IL-27 appears to be associated with this disease. Such dysregulation of cytokines was also found in the heterozygous parents, providing a novel insight into genotype-phenotype correlation of FHL which may encourage future research of this rare disease

Treatment of Infantile Inflammatory Bowel Disease and Autoimmunity by Allogeneic Stem Cell Transplantation in LPS-Responsive Beige-Like Anchor Deficiency

Inflammatory bowel disease (IBD) in young children can be a clinical manifestation of various primary immunodeficiency syndromes. Poor clinical outcome is associated with poor quality of life and high morbidity from the complications of prolonged immunosuppressive treatment and malabsorption. In 2012, mutations in the lipopolysaccharide-responsive beige-like anchor (LRBA) gene were identified as the cause of an autoimmunity and immunodeficiency syndrome. Since then, several LRBA-deficient patients have been reported with a broad spectrum of clinical manifestations without reliable predictive prognostic markers. Allogeneic hematopoietic stem cell transplantation (alloHSCT) has been performed in a few severely affected patients with complete or partial response. Herein, we present a detailed course of the disease and the transplantation procedure used in a LRBA-deficient patient suffering primarily from infantile IBD with immune enteropathy since the age of 6 weeks, and progressive autoimmunity with major complications following long-term immunosuppressive treatment. At 12 years of age, alloHSCT using bone marrow of a fully matched sibling donor-a healthy heterozygous LRBA mutant carrier-was performed after conditioning with a reduced-intensity regimen. During the 6-year follow-up, we observed a complete remission of enteropathy, autoimmunity, and skin vitiligo, with complete donor chimerism. The genetic diagnosis of LRBA deficiency was made post-alloHSCT by detection of two compound heterozygous mutations, using targeted sequencing of DNA samples extracted from peripheral blood before the transplantation

I. Hautkrankheiten

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Wavelet transform selection method for biological signal treatment

This paper presents the development and evaluation of an algorithm for compressing fetal electrocardiographic signals, taken superficially on the mother’s abdomen. This method for acquiring ECG signals produces a great volumen of information that makes it difficult for the records to be stored and transmitted. The proposed algorithm aims for lossless compression of the signal by applying Wavelet Packet Transform to keep errors below the unit, with compression rates over 20:1 and with conserved energy in reconstruction as comparison parameter. For algorithm validation, the signal files provided by PhysioBank DataBase are used

Look at the future -perceptions of fertility counseling and decision-making among adolescents and their parents in the context of hematopoietic stem cell transplantation—experience of one major center for pediatric stem cell transplantation

IntroductionIncreasing survival rates after hematopoietic stem cell transplantation (HSCT) in childhood should put focus on improving the quality of life as adults. An essential aspect is fertility and its preservation. In order to take advantage of the possibility of fertility preservation, fertility counseling should be provided to patients and their parents prior to gonadotoxic therapies.MethodsThe aim of this survey was to analyze the impact of fertility counseling in pediatric stem cell transplantation in patients and their parents using questionnaires designed for the study questions. Fifty-one parents and 7 adolescent patients were interviewed between February 2019 and October 2021 about the counseling, their perceptions of fertility issues, and the nature of decision- making concerning fertility preservation. The study included patients with malignant (e.g., leukemia, lymphoma, neuroblastoma) and nonmalignant diseases (e.g., thalassemia, sickle cell disease, immunodeficiency) who received counseling on fertility preservation before HSCT based on an in-house standard and analysed the impact for both groups.ResultsTwo-thirds of the study participants were concerned about having children and grandchildren respectively; for half of all respondents, the topic of fertility and fertility preservation proved to be hopeful. Forty percent of the study participants were burdened by the risk of possible fertility limitations after HSCT. Concerns about fertility was particularly significant for parents whose children were advised to undergo fertility preservation. Parents of children <12 years found deciding on appropriate measures more difficult. Parents with children >7 years involved their children in the decision. All study participants agreed that fertility counseling had not negatively affected the parent-child relationship. More than 90% of all study participants were in favor of addressing fertility, its potential limitations and fertility preservation measures before HSCT. There was no significant difference between the malignant and the non-malignant cohort in all study questions.DiscussionOverall, the standardized fertility counseling provided in our center of pediatric stem cell transplantation resulted in high satisfaction among patients and their parents. Multiple counseling on infertility risk, including the younger patients in the decision-making and further options after gonadotoxic therapy may increase the satisfaction of the counseled patients and their parents

Supportive Care During Pediatric Hematopoietic Stem Cell Transplantation : Prevention of Infections. A Report From Workshops on Supportive Care of the Paediatric Diseases Working Party (PDWP) of the European Society for Blood and Marrow Transplantation (EBMT)

Specific protocols define eligibility, conditioning, donor selection, graft composition and prophylaxis of graft vs. host disease for children and young adults undergoing hematopoietic stem cell transplant (HSCT). However, international protocols rarely, if ever, detail supportive care, including pharmaceutical infection prophylaxis, physical protection with face masks and cohort isolation or food restrictions. Supportive care suffers from a lack of scientific evidence and implementation of practices in the transplant centers brings extensive restrictions to the child's and family's daily life after HSCT. Therefore, the Board of the Pediatric Diseases Working Party (PDWP) of the European Society for Blood and Marrow Transplantation (EBMT) held a series of dedicated workshops since 2017 with the aim of initiating the production of a set of minimal recommendations. The present paper describes the consensus reached within the field of infection prophylaxis.Peer reviewe