National Institutes of Health State of the Science Symposium in Therapeutic Apheresis: scientific opportunities in extracorporeal photopheresis. Transfus Med Rev. 2015;29:62-70. [PMID: 25459074 DOI: 10.1016/j.tmrv.2014.09.004]

Ex vivo dendritic cell generation-A critical comparison of current approaches

Dendritic cells (DCs) are professional antigen-presenting cells, required for the initiation of naïve and memory T cell responses and regulation of adaptive immunity. The discovery of DCs in 1973, which culminated in the Nobel Prize in Physiology or Medicine in 2011 for Ralph Steinman and colleagues, initially focused on the identification of adherent mononuclear cell fractions with uniquely stellate dendritic morphology, followed by key discoveries of their critical immunologic role in initiating and maintaining antigen-specific immunity and tolerance. The medical promise of marshaling these key capabilities of DCs for therapeutic modulation of antigen-specific immune responses has guided decades of research in hopes to achieve genuine physiologic partnership with the immune system. The potential uses of DCs in immunotherapeutic applications include cancer, infectious diseases, and autoimmune disorders; thus, methods for rapid and reliable large-scale production of DCs have been of great academic and clinical interest. However, difficulties in obtaining DCs from lymphoid and peripheral tissues, low numbers and poor survival in culture, have led to advancements in ex vivo production of DCs, both for probing molecular details of DC function as well as for experimenting with their clinical utility. Here, we review the development of a diverse array of DC production methodologies, ranging from cytokine-based strategies to genetic engineering tools devised for enhancing DC-specific immunologic functions. Further, we explore the current state of DC therapies in clinic, as well as emerging insights into physiologic production of DCs inspired by existing therapies.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice - Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Eighth Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating and categorizing indications for the evidence-based use of therapeutic apheresis (TA) in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Eighth Edition of the JCA Special Issue continues to maintain this methodology and rigor in order to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Eighth Edition, like its predecessor, continues to apply the category and grading system definitions in fact sheets. The general layout and concept of a fact sheet that was introduced in the Fourth Edition, has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of TA in a specific disease entity or medical condition. The Eighth Edition comprises 84 fact sheets for relevant diseases and medical conditions, with 157 graded and categorized indications and/or TA modalities. The Eighth Edition of the JCA Special Issue seeks to continue to serve as a key resource that guides the utilization of TA in the treatment of human disease.

Therapeutic apheresis in kidney transplantation: An updated review

Therapeutic apheresis is a cornerstone of therapy for several conditions in transplantation medicine and is available in different technical variants. In the setting of kidney transplantation, immunological barriers such as ABO blood group incompatibility and preformed donor-specific antibodies can complicate the outcome of deceased- or living- donor transplantation. Postoperatively, additional problems such as antibody-mediated rejection and a recurrence of primary focal segmental glomerulosclerosis can limit therapeutic success and decrease graft survival. Therapeutic apheresis techniques find application in these issues by separating and selectively removing exchanging or modifying pathogenic material from the patient by an extracorporeal aphaeresis system. The purpose of this review is to describe the available techniques of therapeutic aphaeresis with their specific advantages and disadvantages and examine the evidence supporting the application of therapeutic aphaeresis as an adjunctive therapeutic option to immunosuppressive agents in protocols before and after kidney transplantation.

Photopheresis efficacy in the treatment of rheumatoid arthritis: a pre-clinical proof of concept

BACKGROUND

Despite major advances in rheumatoid arthritis outcome, not all patients achieve remission, and there is still an unmet need for new therapeutic approaches. This study aimed at evaluating in a pre-clinical murine model the efficacy of extracorporeal photopheresis (ECP) in the treatment of rheumatoid arthritis, and to provide a relevant study model for dissecting ECP mechanism of action in autoimmune diseases.

METHODS

DBA/1 mice were immunized by subcutaneous injection of bovine collagen type II, in order to initiate the development of collagen-induced arthritis (CIA). Arthritic mice received 3 ECP treatments every other day, with psoralen + UVA-treated (PUVA) spleen cells obtained from arthritic mice. Arthritis score was measured, and immune cell subsets were monitored.

RESULTS

ECP-treated mice recovered from arthritis as evidenced by a decreasing arthritic score over time. Significant decrease in the frequency of Th17 cells in the spleen of treated mice was observed. Interestingly, while PUVA-treated spleen cells from healthy mouse had no effect, PUVA-treated arthritic mouse derived-spleen cells were able to induce control of arthritis development.

CONCLUSIONS

Our results demonstrate that ECP can control arthritis in CIA-mice, and clarifies ECP mechanisms of action, showing ECP efficacy and Th17 decrease only when arthritogenic T cells are contained within the treated sample. These data represent a pre-clinical proof of concept supporting the use of ECP in the treatment of RA in Human.

Frequency of Alterations in Apheresis-Related Abstracts Prior to Publications as Peer-Reviewed Articles

High-quality evidence supporting clinical practice is lacking in apheresis. A potential source of evidence is provided by abstracts submitted to the Annual Meetings of the American Association of Blood Banks (AABB) and the American Society for Apheresis (ASFA). However, there is potential for study conclusions to be altered significantly following abstract presentations prior to publications in peer-reviewed journals. Therefore, we evaluated the discordance rate between apheresis-related meeting abstracts and their corresponding published articles. Abstracts accepted to either AABB or ASFA Annual Meetings from 2005 to 2012 and corresponding PubMed-indexed peer-reviewed articles' abstracts published prior to 9/2014 were reviewed for altered methods, results, and conclusions. When present, changes were evaluated for clinical significance. During the 8-year period, 198 out of 1152 abstracts were published as peer-reviewed articles. Of these, 36 (18.2%) presented discordant results, six of which (16.7%) were potentially clinically significant. An alteration in results (58.3%) was the leading reason for discordance. The discordance rate for ASFA abstracts was significantly higher (HR = 4.69, P = 0.0028) than the AABB ones. However, clinically significant alterations occurred more frequently among AABB abstracts (P = 0.025). Approximately 18% of meeting abstracts demonstrated alterations prior to publication in peer-reviewed journals. Given that approximately one in six changes represented clinically significant alterations, potentially affecting clinical practice, we recommend caution when modifying one's clinical practice based on abstract presentations at Annual Meetings. Future studies involving abstracts from both the International Society for Apheresis and the World Apheresis Association should also be performed.

Monocytes show immunoregulatory capacity on CD4+ T cells in a human in-vitro model of extracorporeal photopheresis

Extracorporeal photopheresis (ECP) is a widely used immunomodulatory therapy for the treatment of various T cell-mediated disorders such as cutaneous T cell lymphoma (CTCL), graft-versus-host disease (GvHD) or systemic sclerosis. Although clinical benefits of ECP are already well described, the underlying mechanism of action of ECP is not yet fully understood. Knowledge on the fate of CD14⁺ monocytes in the context of ECP is particularly limited and controversial. Here, we investigated the immunoregulatory function of ECP treated monocytes on T cells in an in-vitro ECP model. We show that ECP-treated monocytes significantly induce proinflammatory T cell types in co-cultured T cells, while anti-inflammatory T cells remain unaffected. Furthermore, we found significantly reduced proliferation rates of T cells after co-culture with ECP-treated monocytes. Both changes in interleukin secretion and proliferation were dependent on cell-contact between monocytes and T cells. Interestingly, blocking interactions of programmed death ligand 1 (PD-L1) to programmed death 1 (PD-1) in the in-vitro model led to a significant recovery of T cell proliferation. These results set the base for further studies on the mechanism of ECP, especially the regulatory role of ECP-treated monocytes.

Extracorporeal Photochemotherapy Drives Monocyte-to-Dendritic Cell Maturation to Induce Anticancer Immunity

Extracorporeal photochemotherapy (ECP) is a cancer immunotherapy for cutaneous T-cell lymphoma (CTCL) operative in more than 350 centers worldwide. Although its efficacy and favorable safety profile have driven its widespread use, elucidation of its underlying mechanism has been difficult. In this study, we identify the principal contributors to the anticancer immunotherapeutic effects of ECP, with the goal of enhancing potency and broadening applicability to additional malignancies. First, we scaled down the clinical ECP leukocyte-processing device to mouse size. Second, we used that miniaturized device to produce a cellular vaccine that regularly initiated therapeutic antimelanoma immunity. Third, we individually subtracted key factors from either the immunizing inoculum or the treated animal to ascertain their contribution to the in vivo antimelanoma response. Platelet-signaled monocyte-to-dendritic cell (DC) differentiation followed by sorting/processing/presentation of tumor antigens derived from internalized apoptotic tumor cells were absolute requirements. As in clinical ECP, immunogenic cell death of tumor cells was finely titrated by DNA cross-linkage mediated by photoactivated 8-methoxypsoralen (8-MOPA). ECP-induced tumor-loaded DC were effective immunotherapeutic agents only if they were spared exposure to 8-MOPA, indicating that healthy DC are required for ECP. Infusion of responder T cells into naïve tumor-challenged mice established the protective role of stimulated T-cell antitumor immunity. Collectively, these results reveal that selective antitumor effects of ECP are initiated by tumor antigen-loaded, ECP-induced DC, which promote potent collaboration between CD4 and CD8 tumor-specific T cells. These mechanistic insights suggest potential therapeutic applicability of ECP to solid tumors in addition to CTCL.Significance: These findings identify principal cellular contributors to the anticancer immunotherapeutic impact of ECP and suggest this treatment may be applicable to a broad spectrum of immunogenic malignancies. Cancer Res; 78(14); 4045-58. ©2018 AACR.

Apheresis buffy coat collection without photoactivation has no effect on apoptosis, cell proliferation, and total viability of mononuclear cells collected using photopheresis systems

BACKGROUND

Extracorporeal photopheresis (ECP) has been approved for the treatment of advanced cutaneous T-cell lymphoma since 1988. While the precise mechanisms resulting in clinical effects are not fully understood, the photoactivation of mononuclear cells (MNCs) using ultraviolet A (UVA) light and methoxsalen is believed to be the predominant initiating process. The effects of MNC passage through the instrument without photoactivation are unknown. The objective of this study was to evaluate the effect of cell processing through the photopheresis instruments on MNCs.

STUDY DESIGN AND METHODS

Fourteen healthy male subjects underwent one simulated ECP procedure without reinfusion of buffy coats (BCs) in a two-center, open-label, prospective trial. Baseline peripheral blood BC, apheresis-separated untreated BC (BC1), and photoactivated BC (BC2) were evaluated in culture for viability by dye exclusion, apoptosis by annexin V binding, and cell proliferation response to phytohemagglutinin (PHA) stimulation by bromodeoxyuridine (BrdU) incorporation.

RESULTS

Photoactivation (BC2) resulted in 88% expression of annexin V by Day 1 of culture compared with 37 and 39% for baseline and untreated BC1. Cell viability by propidium iodide exclusion was reduced to 10% in BC2 on Day 1 versus 65 and 60% for baseline and BC1. The proliferative response to PHA stimulation was 97% inhibited in the photoactivated BC2.

CONCLUSIONS

These results demonstrate that the mechanical processes used for cell separation and processing of the BC in the absence of photoactivation do not induce a significant amount of apoptosis compared to the standard ECP with methoxsalen and UVA photoactivation.

The mechanisms of rejection in solid organ transplantation

Organ transplantation represents the preferred treatment option for many patients in terminal organ failure. The half-life of transplanted organs, however, is still far from being satisfactory with the vast majority of the organs failing within the first two decades following transplantation. At this stage, it has become apparent that rejection (prevalently mediated by humoral events) remains the primary cause of graft loss after the first year. In this light, studies are underway to better comprehend the immune events underlying graft rejection and novel immunosuppressive strategies are being explored. In this context, therapeutic apheresis techniques, that include therapeutic plasma exchange (TPE), immunoadsorption (IA) and extracorporeal photochemotherapy (ECP), represent an important adjunct in the current immunosuppressive armamentarium. This article briefly reviews our current understanding of the immune process underlying rejection of a solid organ transplant and describes the principal areas of application of therapeutic apheresis techniques in transplantation.

Treatment of Pediatric Acute Graft-versus-Host Disease-Lessons from Primary Immunodeficiency?

Allogeneic hematopoietic stem cell transplant (HSCT) is used to treat increasing numbers of malignant and non-malignant disorders. Despite significant advances in improved human leukocyte antigens-typing techniques, less toxic conditioning regimens and better supportive care, resulting in improved clinical outcomes, acute graft-versus-host disease (aGvHD) continues to be a major obstacle and, although it principally involves the skin, gastrointestinal tract, and liver, the thymus is also a primary target. An important aim following HSCT is to achieve complete and durable immunoreconstitution with a diverse T-cell receptor (TCR) repertoire to recognize a broad range of pathogens providing adequate long-term adaptive T-lymphocyte immunity, essential to reduce the risk of infection, disease relapse, and secondary malignancies. Reconstitution of adaptive T-lymphocyte immunity is a lengthy and complex process which requires a functioning and structurally intact thymus responsible for the production of new naïve T-lymphocytes with a broad TCR repertoire. Damage to the thymic microenvironment, secondary to aGvHD and the effect of corticosteroid treatment, disturbs normal signaling required for thymocyte development, resulting in impaired T-lymphopoiesis and reduced thymic export. Primary immunodeficiencies, in which failure of central or peripheral tolerance is a major feature, because of intrinsic defects in hematopoietic stem cells leading to abnormal T-lymphocyte development, or defects in thymic stroma, can give insights into critical processes important for recovery from aGvHD. Extracorporeal photopheresis is a potential alternative therapy for aGvHD, which acts in an immunomodulatory fashion, through the generation of regulatory T-lymphocytes (Tregs), alteration of cytokine patterns and modulation of dendritic cells. Promoting normal central and peripheral immune tolerance, with selective downregulation of immune stimulation, could reduce aGvHD, and enable a reduction in other immunosuppression, facilitating thymic recovery, restoration of normal T-lymphocyte ontogeny, and complete immunoreconstitution with improved clinical outcome as the ability to fight infections improves and risk of secondary malignancy or relapse diminishes.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice-Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Seventh Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating, and categorizing indications for the evidence-based use of therapeutic apheresis in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the Committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Seventh Edition of the JCA Special Issue continues to maintain this methodology and rigor to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Seventh Edition, like its predecessor, has consistently applied the category and grading system definitions in the fact sheets. The general layout and concept of a fact sheet that was used since the fourth edition has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis in a specific disease entity. The Seventh Edition discusses 87 fact sheets (14 new fact sheets since the Sixth Edition) for therapeutic apheresis diseases and medical conditions, with 179 indications, which are separately graded and categorized within the listed fact sheets. Several diseases that are Category IV which have been described in detail in previous editions and do not have significant new evidence since the last publication are summarized in a separate table. The Seventh Edition of the JCA Special Issue serves as a key resource that guides the utilization of therapeutic apheresis in the treatment of human disease. J. Clin. Apheresis 31:149-162, 2016. © 2016 Wiley Periodicals, Inc.

Apheresis research-more abstracts should be published as full manuscripts to provide more evidence for clinical practice guidelines

High-quality evidence to support clinical practice is lacking in apheresis medicine compared to other therapeutic modalities. A potential source of evidence comes from the abstracts submitted to the Annual Meetings of the American Society for Apheresis (ASFA). Therefore, the goal of this study is to determine the proportion of abstracts from the 2005 to 2012 ASFA Annual Meetings that subsequently became PubMed-indexed publications. Furthermore, we sought to determine the factor(s) that were associated with the likelihood of abstracts to be published as full manuscripts. During the 8-year study period, 684 abstracts were available for analysis (median: 82/year, range: 64-118). Most abstracts (74%) were from US institutions, and 67% of first authors were affiliated with academic centers. There were more abstracts (64%) on therapeutic versus donor apheresis (20%) and cellular therapy (16%). Overall, 16% of the abstracts have been published in PubMed-indexed journals, with a median time of 17 months from the ASFA Annual Meeting (range: 1-96 months). Abstracts whose first authors were affiliated with academic institutions were 3.14 times more likely to have been published than abstracts with ones affiliated with an apheresis organization and/or a community hospital. However, neither the first author's location nor the type of apheresis procedure significantly affected the publication rate after adjusting for other covariates. In conclusion, the rate of publication is low and authors should be encouraged to follow their presentations at the meeting with peer-reviewed manuscripts. This change is essential to provide more published evidence for future apheresis practice guidelines. J. Clin. Apheresis 31:353-358, 2016. © 2015 Wiley Periodicals, Inc.