Walter J.F.M. van der Velden

Early stop polymorphism in human DECTIN-1 is associated with increased candida colonization in hematopoietic stem cell transplant recipients.

Background. Intensive treatment of hematological malignancies with hematopoietic stem cell transplantation (HSCT) is accompanied by a high incidence of opportunistic invasive fungal infection, but individual risk varies significantly. Dectin-1, a C-type lectin that recognizes 1,3-beta-glucans from fungal pathogens, including Candida species, is involved in the initiation of the immune response against fungi. Methods. Screening for the DECTIN-1 Y238X polymorphism within a group of 142 patients undergoing HSCT was correlated with Candida colonization and candidemia. Furthermore, functional studies were performed on the consequences of the polymorphism. Results. Patients bearing the Y238X polymorphism in the DECTIN-1 gene were more likely to be colonized with Candida species, compared with patients bearing wild-type DECTIN-1, necessitating more frequent use of fluconazole in the prevention of systemic Candida infection. Functional assays demonstrated a loss-of-function phenotype of the polymorphism, as shown by the decreased cytokine production by immune cells bearing this polymorphism. Conclusions. The Y238X polymorphism is associated with increased oral and gastrointestinal colonization with Candida species. This suggests a crucial role played by dectin-1 in the mucosal antifungal mechanisms in immunocompromised hosts. The finding that DECTIN-1 polymorphisms rendered HSCT recipients at increased risk for fungal complications may contribute to the selection of high-risk patients who should be considered for antifungal prophylaxis to prevent systemic candidiasis.

Systematic review of agents for the management of gastrointestinal mucositis in cancer patients

PurposeThe aim of this study was to review the available literature and define clinical practice guidelines for the use of agents for the prevention and treatment of gastrointestinal mucositis.MethodsA systematic review was conducted by the Mucositis Study Group of the Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology (MASCC/ISOO). The body of evidence for each intervention, in each cancer treatment setting, was assigned an evidence level. Based on the evidence level, one of the following three guideline determinations was possible: recommendation, suggestion, and no guideline possible.ResultsA total of 251 clinical studies across 29 interventions were examined. Panel members were able to make one new evidence-based negative recommendation; two new evidence-based suggestions, and one evidence-based change from previous guidelines. Firstly, the panel recommends against the use of misoprostol suppositories for the prevention of acute radiation-induced proctitis. Secondly, the panel suggests probiotic treatment containing Lactobacillus spp., may be beneficial for prevention of chemotherapy and radiotherapy-induced diarrhea in patients with malignancies of the pelvic region. Thirdly, the panel suggests the use of hyperbaric oxygen as an effective means in treating radiation-induced proctitis. Finally, new evidence has emerged which is in conflict with our previous guideline surrounding the use of systemic glutamine, meaning that the panel is unable to form a guideline. No guideline was possible for any other agent, due to inadequate and/or conflicting evidence.ConclusionsThis updated review of the literature has allowed new recommendations and suggestions for clinical practice to be reached. This highlights the importance of regular updates.

The Y238X Stop Codon Polymorphism in the Human β-Glucan Receptor Dectin-1 and Susceptibility to Invasive Aspergillosis

BACKGROUND Dectin-1 is the major receptor for fungal β-glucans on myeloid cells. We investigated whether defective Dectin-1 receptor function, because of the early stop codon polymorphism Y238X, enhances susceptibility to invasive aspergillosis (IA) in at-risk patients. METHODS Association of Dectin-1 Y238X polymorphism with occurrence and clinical course of IA was evaluated in 71 patients who developed IA post hematopoietic stem cell transplantation (HSCT) and in another 21 non-HSCT patients with IA. The control group consisted of 108 patients who underwent HSCT. Functional studies were performed to investigate consequences of the Y238X Dectin-1 polymorphism. RESULTS The Y238X allele frequency was higher in non-HSCT patients with IA (19.0% vs 6.9%-7.7%; P < .05). Heterozygosity for Y238X polymorphism in HSCT recipients showed a trend toward IA susceptibility (odds ratio, 1.79; 95% CI, .77-4.19; P = .17) but did not influence clinical course of IA. Functional assays revealed that although peripheral blood mononuclear cells with defective Dectin-1 function due to Y238X responded less efficiently to Aspergillus, corresponding macrophages showed adequate response to Aspergillus. CONCLUSIONS Dectin-1 Y238X heterozygosity has a limited influence on susceptibility to IA and may be important in susceptible non-HSCT patients. This is partly attributable to redundancy inherent in the innate immune system. Larger studies are needed to confirm these findings.

Response to Rituximab-Based Therapy and Risk Factor Analysis in Epstein Barr Virus–Related Lymphoproliferative Disorder After Hematopoietic Stem Cell Transplant in Children and Adults: A Study From the Infectious Diseases Working Party of the European Group for Blood and Marrow Transplantation

BACKGROUND  The objective of this analysis was to investigate prognostic factors that influence the outcome of Epstein-Barr virus (EBV)-related posttransplant lymphoproliferative disorder (PTLD) after a rituximab-based treatment in the allogeneic hematopoietic stem cell transplant (HSCT) setting. METHODS  A total of 4466 allogeneic HSCTs performed between 1999 and 2011 in 19 European Group for Blood and Marrow Transplantation centers were retrospectively analyzed for PTLD, either biopsy-proven or probable disease. RESULTS  One hundred forty-four cases of PTLD were identified, indicating an overall EBV-related PTLD frequency of 3.22%, ranging from 1.16% for matched-family donor, 2.86% for mismatched family donor, 3.97% in matched unrelated donors, and 11.24% in mismatched unrelated donor recipients. In total, 69.4% patients survived PTLD. Multivariable analysis showed that a poor response of PTLD to rituximab was associated with an age ≥30 years, involvement of extralymphoid tissue, acute GVHD, and a lack of reduction of immunosuppression upon PTLD diagnosis. In the prognostic model, the PTLD mortality increased with the increasing number of factors: 0-1, 2, or 3 factors being associated with mortality of 7%, 37%, and 72%, respectively (P < .0001). Immunosuppression tapering was associated with a lower PTLD mortality (16% vs 39%), and a decrease of EBV DNAemia in peripheral blood during therapy was predictive of better survival. CONCLUSIONS  More than two-thirds of patients with EBV-related PTLD survived after rituximab-based treatment. Reduction of immunosuppression was associated with improved outcome, whereas older age, extranodal disease, and acute graft-vs-host disease predicted poor outcome.

Safety and tolerability of the antimicrobial peptide human lactoferrin 1-11 (hLF1-11)

BackgroundThe treatment of patients with haematological malignancies by means of haematopoietic stem cell transplantation (HSCT) is often accompanied by life threatening infections. With emerging antimicrobial resistance there is an increased need for new agents, with a beneficial safety profile. Therefore we evaluated the safety of the promising new antimicrobial peptide human lactoferrrin 1-11 (hLF1-11) in healthy volunteers and patients.MethodsWe undertook a sequential, randomised, double-blind, placebo-controlled study using ascending single (0.005, 0.05, 0.5, 5 mg) and multiple intravenous doses (0.5, 5 mg) in healthy volunteers, and open-label, single intravenous 5 mg doses in autologous HSCT recipients.ResultsSingle and multiple doses of hLF1-11 were tolerable up to 5 mg intravenously in healthy volunteers, while 5 mg single dose was tolerable in patients. Elevations in transaminases possibly related to treatment were reversible and not serious.ConclusionThe new antimicrobial hLF1-11 is well tolerated in healthy volunteers with repeated daily doses up to 5 mg. The side-effect profile is very favourable for an antimicrobial, the only undesirable effect being a possible elevation of transaminases, which may be related to hLF1-11 although the current data do not allow conclusive interpretation of treatment relationship. A lower dose is recommended for the forthcoming multiple dosing studies in HSCT patients.Trial registrationClinicalTrials.gov: nct00509938.

Intestinal Damage Determines the Inflammatory Response and Early Complications in Patients Receiving Conditioning for a Stem Cell Transplantation

Background Stem cell transplantation (SCT) is still complicated by the occurrence of fever and inflammatory complications attributed to neutropenia and subsequent infectious complications. The role of mucosal barrier injury (MBI) of the intestinal tract therein has received little attention. Methods We performed a retrospective analysis in 163 SCT recipients of which data had been collected prospectively on intestinal damage (citrulline), inflammation (C-reactive protein), and neutrophil count. Six different conditioning regimens were studied; 5 myeloablative (MA) and 1 non-myeloablative (NMA). Linear mixed model multivariate and AUC analyses were used to define the role of intestinal damage in post-SCT inflammation. We also studied the relationship between the degree of intestinal damage and the occurrence of early post-SCT complications. Results In the 5 MA regimen there was a striking pattern of inflammatory response that coincided with the occurrence of severe intestinal damage. This contrasted with a modest inflammatory response seen in the NMA regimen in which intestinal damage was limited. With linear mixed model analysis the degree of intestinal damage was shown the most important determinant of the inflammatory response, and both neutropenia and bacteremia had only a minor impact. AUC analysis revealed a strong correlation between citrulline and CRP (Pearson correlation r = 0.96). Intestinal damage was associated with the occurrence of bacteremia and acute lung injury, and influenced the kinetics of acute graft-versus-host disease. Conclusion The degree of intestinal damage after myeloablative conditioning appeared to be the most important determined the inflammatory response following SCT, and was associated with inflammatory complications. Studies should explore ways to ameliorate cytotoxic therapy-induced intestinal damage in order to reduce complications associated with myeloablative conditioning therapy.

Mucosal barrier injury, fever and infection in neutropenic patients with cancer: introducing the paradigm febrile mucositis

Infection remains one of the most prominent complications after cytotoxic treatment for cancer. The connection between neutropenia and both infections and fever has long been designated as ‘febrile neutropenia’, but treatment with antimicrobial agents and haematopoietic growth factors has failed to significantly reduce its incidence. Moreover, emerging antimicrobial resistance is becoming a concern that necessitates the judicious use of available antimicrobial agents. In addition to neutropenia, patients who receive cytotoxic therapy experience mucosal barrier injury (MBI) or ‘mucositis’. MBI creates a port‐de‐entrée for resident micro‐organisms to cause blood stream infections and contributes directly to the occurrence of fever by disrupting the highly regulated host‐microbe interactions, which, even in the absence of an infection, can result in strong inflammatory reactions. Indeed, MBI has been shown to be a pivotal factor in the occurrence of inflammatory complications after cytotoxic therapy. Hence, the concept ‘febrile neutropenia’ alone may no longer suffice and a new concept ‘febrile mucositis’ should be recognized as the two are at least complementary. This review we summarizes the existing evidence for both paradigms and proposes new therapeutic approaches to tackle the perturbed host‐microbe interactions arising from cytotoxic therapy‐induced tissue damage in order to reduce fever in neutropenic patients with cancer.

Decreased Levels of Circulating IL17-Producing CD161+CCR6+ T Cells Are Associated with Graft-versus-Host Disease after Allogeneic Stem Cell Transplantation

The C-type lectin-like receptor CD161 is a well-established marker for human IL17-producing T cells, which have been implicated to contribute to the development of graft-versus-host disease (GVHD) after allogeneic stem cell transplantation (allo-SCT). In this study, we analyzed CD161+ T cell recovery, their functional properties and association with GVHD occurrence in allo-SCT recipients. While CD161+CD4+ T cells steadily recovered, CD161hiCD8+ T cell numbers declined during tapering of Cyclosporine A (CsA), which can be explained by their initial growth advantage over CD161neg/lowCD8+ T cells due to ABCB1-mediated CsA efflux. Interestingly, occurrence of acute and chronic GVHD was significantly correlated with decreased levels of circulating CD161+CD4+ as well as CD161hiCD8+ T cells. In addition, these subsets from transplanted patients secreted high levels of IFNγ and IL17. Moreover, we found that CCR6 co-expression by CD161+ T cells mediated specific migration towards CCL20, which was expressed in GVHD biopsies. Finally, we demonstrated that CCR6+ T cells indeed were present in these CCL20+ GVHD-affected tissues. In conclusion, we showed that functional CD161+CCR6+ co-expressing T cells disappear from the circulation and home to GVHD-affected tissue sites. These findings support the hypothesis that CCR6+CD161-expressing T cells may be involved in the immune pathology of GVHD following their CCL20-dependent recruitment into affected tissues.

The incidence of acute graft-versus-host disease increases with Candida colonization depending the dectin-1 gene status.

Dectin-1 plays an important role in antifungal immunity. The dectin-1 Y238X polymorphism, which results in decreased Th17 responses, is associated with increased Candida colonization of stem cell transplantation (SCT) recipients. In this study we found no impact of the polymorphism on the incidence of graft-versus-host disease (GvHD), or on disease-free and overall survival in these SCT recipients. However, patients from patient-donor pairs bearing the wild-type allele who where colonized with Candida had a significant increased incidence of acute GvHD compared to non-colonized patients (OR=2.6, P=0.04). The fact that this was not the case in patients from pairs with the Y238X polymorphism (OR=1.2, ns) suggests that despite increased colonization defective dectin-1 signaling might have prevented an impact of Candida colonization on the incidence of acute GvHD to occur. These are the first human data showing a role for Candida in the pathogenesis of acute GvHD. The mechanism could involve C-type lectin receptor mediated Th17 responses.

Targeting the IL17 Pathway for the Prevention of Graft-Versus-Host Disease

Graft-versus-host disease (GVHD) is still a major complication of allogeneic stem cell transplantation (allo-SCT). The pathophysiology of GVHD is a multistep process initiated by tissue damage and proinflammatory cytokine cascades induced by the pretransplantation conditioning therapy. This eventually results in Th1-driven tissue damage. However, increasing evidence indicates the involvement of IL17-producing T cells in GVHD pathogenesis. Both CD4(+) and CD8(+) IL17-producing T cells are suspected of initiating the Th1 response and aggravating tissue inflammation, resulting in full-blown GVHD. In this review, we discuss the involvement of IL17-producing T cells in GVHD and the factors involved in their expansion, differentiation, and activation. Different dendritic cell (DC) subsets, such as plasmacytoid DCs and DC NK lectin group receptor 1(+) myeloid DCs have the capability to stimulate Th/Tc17 responses through the release of cytokines. Pivotal cytokines include IL1β, IL6, IL23, and TGFβ, which are known to drive differentiation and expansion of IL17-producing T cells, and these cytokines are highly elevated in patients after allo-SCT. Potent activators of these DC subsets are motifs that are released upon tissue damage and microbial exposure during allo-SCT. These motifs aggravate the Th/Tc17 response via the activation of various pathogen recognition receptors, thereby initiating and perpetuating GVHD. A more comprehensive understanding of the factors and DC subsets driving the IL17 pathway will result in developing and testing novel therapeutic approaches for the prevention of GVHD.