Extracorporeal photopheresis: technique, established and novel indications

Novel insights in the clinical management of hyperimmune patients before and after transplantation

Despite improvements in anti-Human Leucocyte Antigens antibody detection, identification, and characterization offer a better in peri-operative management techniques, antibodies remain a serious cause of morbidity and mortality for patients both before and after organ transplantation. Hyperimmune patients are disadvantaged by having to wait longer to receive an organ from a suitably matched donor. They could benefit from desensitization protocols in both pre- and post-transplantation period. Clinical studies are underway to highlight which best desensitization strategies could be assure the best outcome in both heart and kidney transplantation. Although most clinical evidence about desensitization strategies by using anti-CD20 monoclonal antibodies, proteasome inhibitors, anti-CD38 monoclonal antibodies, interleukin-6 blockade, cysteine protease and complement inhibitors, comes from kidney transplantation studies, many of the debated novel concepts can be easily applied to desensitization also in heart transplantation. Here, we discuss the candidates and recipients' management by using most common standard of care and novel therapeutics, desensitization endpoints, and strategies for future studies.

Apoptosis induction by extracorporeal photopheresis is enhanced by increasing the 8-methoxypsoralen concentration and by replacing plasma with saline

BACKGROUND

Extracorporeal photopheresis (ECP), an apheresis-based therapy for various immunological diseases, works mainly by inducing apoptosis in lymphocytes. Several factors influence the efficacy of ECP with the photosensitizer 8-methoxypsoralen (8-MOP) and ultraviolet light A (UVA). This study aimed to optimize treatment by varying the 8-MOP starting concentration and the cell suspension medium.

MATERIALS AND METHODS

All patients (n = 13) included in this study received photopheresis as medically indicated. Cells collected with a Spectra Optia apheresis system were suspended in plasma or physiological saline (NaCl) and incubated with 200 ng/ml versus 340 ng/ml photosensitizer before UVA irradiation (Macogenic G2 or UVA PIT system). Lymphocyte apoptosis and caspase activity were analyzed by flow cytometry and fluorimetry, and residual 8-methoxypsoralen concentrations by liquid chromatography-mass spectrometry.

RESULTS

Raising the 8-MOP starting concentration significantly increased lymphocyte apoptosis, with values of 22% versus 35% (plasma) and 28%-46% (NaCl) at 24 h post-ECP and 37% versus 86% (plasma) and 74% versus 97% (NaCl) at 48 h for 200 ng/ml versus 340 ng/ml. Pre-transfusion residual 8-MOP levels were 168 ng/ml (plasma) and 162 ng/ml (NaCl) versus 290 ng/ml (plasma) and 266 ng/ml (NaCl) for the lower versus higher dose, respectively.

DISCUSSION

Hence, 8-MOP concentration influences the efficacy of photopheresis as lymphocyte apoptosis rates were significantly higher with the higher starting concentration and with NaCl versus plasma. This indicates that increased 8-MOP starting doses and saline as additional suspension medium could help in improving ECP's efficacy.

Photopheresis Abates the Anti-HLA Antibody Titer and Renal Failure Progression in Chronic Antibody-Mediated Rejection

Simple Summary

The most common cause of late allograft failure is chronic active antibody-mediated rejection (ABMR), but no effective therapy is available. Different immunosuppressive drugs in combination with procedures that remove serum antibodies have been used and the results have not shown to improve graft and patient outcome, but only an increased risk of adverse events. Extracorporeal pho-topheresis (ECP) is leukapheresis-based immunomodulatory therapy not associated with adverse effect, in which lymphocytes treat-ed with 8-methoxypsoralen (8-MOP) are irradiated with ultraviolet-A (UVA) ex vivo and re-infused into the patient. In this study we investigated therapeutic long-term effect of ECP in patients with biopsy proved chronic ABMR.

Abstract

Objective: Chronic renal antibody-mediated rejection (ABMR) is a common cause of allograft failure, but an effective therapy is not available. Extracorporeal photopheresis (ECP) has been proven successful in chronic lung and heart rejection, and graft versus host disease. The aim of this study was to evaluate the effectiveness of ECP in chronic ABMR patients. Patients and Methods: We investigated ECP treatment in 14 patients with biopsy-proven chronic ABMR and stage 2–3 chronic renal failure. The primary aim was to e valuate the eGFR lowering after 1 year of ECP therapy. The ECP responders (R) showed eGFR reduction greater than 20% vs the basal levels. We also evaluated the effectiveness of ECP on proteinuria, anti-HLA antibodies (HLAab), interleukin 6 (IL-6) serum levels, and CD3, CD4, CD8, CD19, NK, Treg and T helper 17 (Th17) circulating cells. Results: Three patients dropped out of the study. The R patients were eight (72.7%) out of the 11 remaining patients. Because ECP was not associated with any adverse reaction, the R patients continued such treatment for up to 3 years, showing a persisting eGFR stabilization. Twenty four hour proteinuria did not increase in the R patients over the follow-up when compared to the non-responder patients (NR). In the R patients, the HLAab levels were reduced and completely cleared in six out of eight patients when compared with the NR patients. The NR HLAab levels also increased after the discontinuation of the ECP. The ECP in the R patients showed a decrease in CD3, CD4, CD8, CD19, and NK circulating cells. The ECP treatment in the R patients also induced Tregs and Th17 cell increases, and a decrease of the IL-6 serum levels. Conclusions: ECP abates the HLAab titer and renal failure progression in patients with chronic renal ABMR, modulating the immune cellular and humoral responses.

Validation of an apoptosis assay for extracorporeal photopheresis

OBJECTIVES

This validation study investigated a flow cytometric apoptosis assay according to good manufacturing practice (GMP).

BACKGROUND

Extracorporeal photopheresis (ECP) is a treatment for various immunological diseases and cutaneous T-cell lymphomas. It is based on the induction of apoptosis by 8-methoxypsoralene and ultraviolet A light. The quantification of apoptosis is therefore essential for ECP improvements. However, despite numerous publications on apoptosis, validated technical details are lacking.

METHODS AND MATERIALS

Mononuclear cells were collected by apheresis and treated by ECP or camptothecin. Samples taken before and after ECP were cultured for 24, 48 and 72 h and analysed for apoptosis and viability of T cells and monocytes by flow cytometry with Annexin V and 7-AAD staining. Accuracy of the assay, intra- and inter-assay precision and the pre-analytical and analytical stability of the analytes were the investigated parameters.

RESULTS

Our data indicate that the median intra- and inter-assay precision coefficient of variation for T cells was 3.86% and 4.80%, respectively. Pre-analytical stability of T cells and monocytes was ensured during short-term storage for up to 2 h on ice. After staining, analytical stability was limited to 30 min, likely because of ongoing apoptosis and loss of monocytes due to plastic adhesion.

CONCLUSION

The results of this validation study show that the assay is GMP-compliant and that its reliability, accuracy and precision are acceptable. While pre-analytical stability of the cells was compatible with on-site procedures, our analytical stability data indicate that this assay is not suited for batch mode analysis of ECP products.

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.

Iron deficiency anemia associated with extracorporeal photopheresis: A retrospective analysis

BACKGROUND

Extracorporeal photopheresis (ECP) is associated with few adverse effects. We have anecdotally noted patients treated with long-term ECP develop iron deficiency anemia (IDA).

METHODS

We performed a retrospective chart review of adult patients who received ECP for any indication at Mayo Clinic Rochester and Mayo Clinic Arizona. The primary objective was to describe the cumulative incidence of IDA at 1 year of ECP therapy.

RESULTS

A total of 123 patients were eligible for analysis. Graft-vs-host disease was the most common indication for ECP (n = 76, 61.8%). At 1 year of ECP therapy, the cumulative incidence of IDA was 24.1% (95% CI, 14.2%-32.9%). At 5 years, the cumulative incidence of IDA was 68.3% (95% CI, 38%-83.8%). Risk factors for the development of IDA included: cumulative number of ECP sessions (HR 1.34, 95% CI, 1.05-1.73 per 10 additional sessions, P = .022), an indication for ECP of solid organ transplant rejection (compared to cutaneous T-cell lymphoma, HR 5.46, 95% CI, 2.06-14.49, P < .001), and proton pump inhibitor use at baseline (HR 2.15, 95% CI, 1.1-4.21, P = .03). Iron supplementation was initiated in 29 of 37 evaluable patients who developed IDA, with a cumulative incidence of supplementation in 77.2% patients within 3 months of recognition of IDA (95% CI, 55.8%-88.3%). Hemoglobin normalized in 50.1% of patients started on iron supplementation for IDA within 7 months (95% CI, 25.2%-66.7%).

CONCLUSIONS

Iron deficiency anemia is common in patients receiving long-term ECP and occurs throughout ECP therapy. IDA resolved with iron supplementation in half of patients.

A standardized methodical approach to characterize the influence of key parameters on the in vitro efficacy of extracorporeal photopheresis

Extracorporeal photopheresis (ECP) is an autologous immunomodulatory cell therapy that consists of the ex vivo collection of mononuclear cells (MNCs), which are irradiated with UVA in the presence of the photosensitizing agent 8-methoxypsoralen (8-MOP) to induce cell apoptosis. This photoactivated cell preparation is then reinfused into the patient. While the clinical benefits of ECP are well-demonstrated, no study has yet characterized the influence of variations in the composition of the cell preparation on the efficacy of ECP in vitro. Here, we describe a standardized methodology for the in vitro assessment of ECP that uses the human lymphoma T-cell line and mimics the clinical procedure. By quantifying cell apoptosis, inhibition of cell proliferation, and 8-MOP consumption, we used this approach to characterize the specific influence of key variables on the cellular response to ECP. We found that (i) increases in hematocrit and plasma concentrations attenuated the cellular response to ECP; (ii) plasma concentration was the only variable tested that influenced 8-MOP consumption; and (iii) the loss of efficacy due to variations in the concentration of certain blood components could be counteracted by modulating the UVA dose. This methodology may enable evaluation of other leukapheresis preparation protocols and better determination of the optimal working parameters for ECP.

A method for the quantification of 8-methoxypsoralen by mass spectrometry for offline extracorporeal photopheresis

An LC-MS/MS assay for analysis of 8-methoxypsoralene was developed as assay to monitor extracorporeal photopheresis. This allows quantification of 8-MOP adhering to plastic surface and of the UV light-dependent decay constant.

Extracorporeal photopheresis in solid organ transplant-associated acute graft-versus-host disease

BACKGROUND

Extracorporeal photopheresis (ECP) culls pathogenic T lymphocytes, be these the clones of cutaneous T-cell lymphoma, or mediators of chronic graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation (BMT-GVHD). Whether or not ECP may have an effect in the rarer instances of solid organ transplantation-associated GVHD (SOT-GVHD) is unclear. Mortality rates in SOT-GVHD rival those of transfusion-associated GVHD, with fatalities preceded by pancytopenia and peripheral blood chimerism (PBC) levels exceeding 20%. ECP has been described in two SOT-GVHD cases to date, with one surviving.

STUDY DESIGN AND METHODS

Clinicolaboratory features (including HLA relationships) in a case of multivisceral transplantation were reviewed from the time of surgery to the onset and progression of SOT-GVHD. ECP, which was introduced as a less immunosuppressive and more selective intervention, was assessed for its effect on serial PBC (as measured by short-tandem-repeat analysis) and clinical outcome.

RESULTS

Multivisceral SOT-GVHD manifested with erythroderma, neutropenic sepsis, and PBC increasing from 6% on Posttransplant Day (PTD) 38 to 78% by PTD 60 (at a doubling time of 6 days despite corticosteroids). ECP was administered on PTDs 62 and 67 and was associated with the first evidence of PBC decay to 67% on PTD 69. Death nevertheless ensued on the last day of salvage antithymocyte globulin (PTDs 69-73) despite further PBC reduction to 41%.

CONCLUSION

Further study is needed to determine if the sooner or more frequent application of ECP might attenuate the high case fatality rates of SOT-GVHD.