Diagnosis and treatment of human adenovirus infection following allogeneic stem cell transplantation

BackgroundHuman adenovirus (HAdV) infections are increasingly recognized as a frequent cause of potentially fatal infections in paediatric allogeneic stem cell transplantation (SCT) recipients.AimTo analyse data in the field of diagnosis and treatment of human adenovirus infection following allogeneic haematopoietic stem cell transplantation.Materials/MethodsA review of PubMed references based on evidence-based recommendations and own experience.ResultsIncidence of HAdV infections is higher in paediatric than in adult SCT recipients, which might be related to the high exposure to HAdV at young age, while HAdV-specific immunity has still to be mounted, especially in children receiving a T-cell depleted graft and/or a graft of another than an HLA-genotypically identical related donor. In subsequent retrospective and prospective studies evidence has been provided that monitoring of serum/plasma by RQ-PCR is a sensitive tool for the recognition of patients at risk of potentially fatal infection, and that quantification of HAdV DNA is instrumental to make decisions on clinical intervention, and to accurately monitor the response to antiviral therapy. Several antiviral drugs (ribavirin and cidofovir) are being used to treat HAdV infections and variable efficacy has been reported. Reports on possible clinical efficacy of drugs are often biased, because of the heterogeneity of patients and lack of information about the level of simultaneous immune reconstitution. Data from several retrospective and prospective studies have demonstrated that lymphocyte recovery is essential for the elimination of HAdV infection.ConclusionsBased on current knowledge, boosting of immunity by tapering of immunosuppression or infusion of lymphocytes from the donor seems to be an essential element in treatment of patients at risk of HAdV viraemia. Simultaneous analysis of lymphocyte reconstitution will further improve the identification of individuals that will require and benefit most from the immunotherapeutic interventions

IMPLEMENTATION ROUTES OF ADVANCED THERAPY MEDICINAL PRODUCTS DEVELOPED IN ACADEMIA IN CLINICAL PRACTICE IN THE NETHERLANDS

Clinical Pharmacy and Toxicolog

Co-ordinated isolation of CD8(+) and CD4(+) T cells recognizing a broad repertoire of cytomegalovirus pp65 and IE1 epitopes for highly specific adoptive immunotherapy

Background aims. Adoptive transfer of cytomegalovirus (CMV)-specific memory T cells can be used for treatment of CMV reactivation after allogeneic stem cell transplantation. As co-ordinated CD8(+) and CD4(+) T cells specific for a broad repertoire of CMV epitopes may be most effective for adoptive immunotherapy, the aim of this study was to isolate these cells from peripheral blood of CMV seropositive donors, irrespective of their HLA type. Methods. Activation of CMV-specific CD8(+) and CD4(+) T cells was compared after stimulation of donor peripheral blood with minimal epitope peptides, pools of overlapping 15-mer peptides or full-length protein. Furthermore, the kinetics of interferon (IFN)-gamma production after stimulation was analyzed to determine the optimal time-point for IFN-gamma-based isolation of CMV-specific T cells. The specificity, phenotype and functionality of generated T-cell lines were analyzed. Results. CMV protein-spanning 15-mer peptide pools induced simultaneous activation of both CD8(+) and CD4(+) CMV-specific T cells, while full-length CMV protein only efficiently activated CD4(+) CMV-specific T cells. Isolation of IFN-gamma-secreting cells at the peak of the IFN-gamma response after 4-h stimulation with CMV pp65 and IE1 peptide pools resulted in efficient enrichment of CMV-specific T cells. The T-cell lines contained high frequencies of CD8(+) and CD4(+) T cells recognizing multiple CMV pp65 and IE1 epitopes, and produced IFN-gamma and tumor necrosis factor (TNF)-alpha upon specific restimulation. Conclusions. This study provides a feasible strategy for the rapid generation of clinical-grade CD8(+) and CD4(+) T-cell lines with high specificity for multiple CMV pp65 and IE1 epitopes, which may be used for effective adoptive immunotherapy

Hurdles in clinical implementation of academic advanced therapy medicinal products: A national evaluation

Personalised Therapeutic

T-cell lines specific for peptides of adenovirus hexon protein and devoid of alloreactivity against recipient cells can be obtained from HLA-haploidentical donors

Human adenovirus (HAdV) infection may cause life-threatening complications in recipients of hematopoietic stem cell transplantation (HSCT), the highest risk being observed in children given T-cell depleted haploidentical allografts. The effectiveness of pharmacologic therapy for HAdV infection is suboptimal. Recently, cell therapy was demonstrated to offer a unique opportunity to restore antiviral immune surveillance, leading to clearance of infection and prevention/treatment of disease. However, infusion of insufficiently selected HAdV-specific T cells in haplo-HSCT may increase the risk of graft-versus-host disease. We conducted scale-up experiments to validate a method of in vitro culture to expand T cells specific for HAdV from donor peripheral blood mononuclear cells (PBMC), based on stimulation with a pool of five 30-mer peptides derived from HAdV5 hexon protein, for use in recipients of haplo-HSCT. A total of 21 T-cell lines that included a majority of CD4 T lymphocytes, were generated. Nineteen of the 21 T-cell lines proliferated specifically against HAdV. The 2 nonspecific, and 3 T-cell lines with lower specific activity, included a median of 48% CD8 T cells. The 19 HAdV-specific T-cell lines showed a median 357-fold decrease in alloreactivity, compared with proliferation of noncultured donor PBMC in response to recipient PBMC, only 4/19 T-cell lines showing residual alloreactivity. Our data indicate that HAdV-specific CD4 T-cell lines with efficient in vitro antiviral response and low/undetectable alloreactivity against recipient targets may be expanded from PBMC of most human leukocyte antigen-haploidentical HSCT donors after stimulation with HAdV hexon protein-derived peptides. These T cells may be safely employed for adoptive treatment of HAdV complications

Mesenchymal Stromal Cell Therapy Is Associated With Increased Adenovirus-Associated but Not Cytomegalovirus-Associated Mortality in Children With Severe Acute Graft-Versus-Host Disease

Transplantation and immunomodulatio

High Titers of Pre-existing Adenovirus Serotype-Specific Neutralizing Antibodies in the Host Predict Viral Reactivation After Allogeneic Stem Cell Transplantation in Children

Background. Human adenovirus (HAdV) infections are frequent in children after allogeneic stem cell transplantation (SCT) and may become fatal. Whether these infections occur through reactivation of endogenous virus or transmission via the graft remains a matter of debate. Methods. In a cohort of 24 pediatric patients who received SCT, infections with 1 or more of 5 serotypes of HAdV (1, 2, 5, 6, and 31) were detected by culture. Neutralizing antibody (NAb) titers were measured in vitro by means of a virus neutralization assay. Results. In 11 patients the infection was restricted to 1 site as demonstrated by culture only, and in 13 patients the HAdV infection was disseminated because plasma samples contained HAdV DNA. The 5 most commonly encountered HAdV serotypes caused 35 infectious episodes after SCT. Serum titers of NAb against these 5 serotypes of HAdV were measured before and after transplantation. High titers of NAb against a certain serotype in the recipient prior to SCT, reflecting previous infection, appeared to predispose for infection with the same serotype after SCT. In only 1 case of 41 independent samples of graft material, a very low level of HAdV DNA was detected. Antibody responses after SCT were detected in 21 of 35 infectious episodes. Conclusions. Together, these data suggest that adenoviral complications after SCT are caused by reactivation of endogenous persistent HAdV rather than by de novo infection from the donor or environment. This finding may offer a strategy of prophylactic treatment of high-risk patients before SCT to prevent infectious complications after allogeneic SCT.Transplantation and immunomodulatio

High titres of pre-existing adenovirus serotype-specific neutralizing antibodies predict viral reactivation after allogeneic stem cell transplantation in children

Transplantation and immunomodulatio

Extensive Cross-Reactivity of CD4(+) Adenovirus-Specific T Cells: Implications for Immunotherapy and Gene Therapy

Adenovirus (Ad)-specific T-cell responses in healthy adult donors were investigated. Ad5, inactivated by methylene blue plus visible light, induced proliferation and gamma interferon (IFN-γ) production in peripheral blood mononuclear cells of the majority of donors. Responding T cells were CD4(+) and produced IFN-γ upon restimulation with infectious Ad5 and Ads of different subgroups. T-cell clones showed distinct cross-reactivity patterns recognizing Ad serotypes from either one subgroup (C), two subgroups (B and C), or three subgroups (A, B, and C). This cross-reactivity of Ad-specific T cells has relevance both for Ad-based gene therapy protocols, as well as for the feasibility of T-cell-mediated adoptive immunotherapy in recipients of an allogeneic stem cell transplantation