Cutaneous and noncutaneous disorders treated with extracorporeal photopheresis

Pathogen-reduced PRP blocks T-cell activation, induces Treg cells, and promotes TGF-β expression by cDCs and monocytes in mice

Alloimmunization against platelet-rich plasma (PRP) transfusions can lead to complications such as platelet refractoriness or rejection of subsequent transfusions and transplants. In mice, pathogen reduction treatment of PRP with UVB light and riboflavin (UV+R) prevents alloimmunization and appears to induce partial antigen-specific tolerance to subsequent transfusions. Herein, the in vivo responses of antigen-presenting cells and T cells to transfusion with UV+R-treated allogeneic PRP were evaluated to understand the cellular immune responses leading to antigen-specific tolerance. Mice that received UV+R-treated PRP had significantly increased transforming growth factor β (TGF-β) expression by CD11b+ CD4+ CD11cHi conventional dendritic cells (cDCs) and CD11bHi monocytes (P < .05). While robust T-cell responses to transfusions with untreated allogeneic PRP were observed (P < .05), these were blocked by UV+R treatment. Mice given UV+R-treated PRP followed by untreated PRP showed an early significant (P < .01) enrichment in regulatory T (Treg) cells and associated TGF-β production as well as diminished effector T-cell responses. Adoptive transfer of T-cell-enriched splenocytes from mice given UV+R-treated PRP into naive recipients led to a small but significant reduction of CD8+ T-cell responses to subsequent allogeneic transfusion. These data demonstrate that pathogen reduction with UV+R induces a tolerogenic profile by way of CD11b+ CD4+ cDCs, monocytes, and induction of Treg cells, blocking T-cell activation and reducing secondary T-cell responses to untreated platelets in vivo.

Pathogen reduction with riboflavin and ultraviolet light induces a quasi-apoptotic state in blood leukocytes

BACKGROUND

Alloimmunization to platelet-rich plasma (PRP) transfusions can cause adverse reactions such as platelet refractoriness or transplant rejection. Pathogen reduction treatment with ultraviolet light and riboflavin (UV + R) of allogeneic PRP was shown to reduce allogeneic antibody responses and confer partial antigen-specific immune tolerance to subsequent transfusions in mice. Studies have shown that UV + R was effective at both rapidly killing donor white blood cells (WBCs) and reducing their ability to stimulate an allogeneic response in vitro. However, the manner in which UV + R induces WBC death and its associated role in the immune response to treated PRP is unknown.

METHODS AND MATERIALS

This study evaluates whether UV + R causes WBC apoptosis by examining phosphatidylserine exposure on the plasma membrane, membrane asymmetry, caspase activity, and chromatin condensation by flow cytometry. The immunogenicity of WBCs killed with UV + R versus apoptotic or necrotic pathways was also examined in vivo.

RESULTS

WBCs after UV + R exhibited early apoptotic-like characteristics including phosphatidylserine exposure on the outer leaflet of the plasma membrane and loss of membrane asymmetry, but unlike canonical apoptotic cells, caspase activity and chromatin condensation were not apparent. However, in vivo studies demonstrated, unlike untreated or necrotic WBCs, both apoptotic WBCs and UV + R-treated WBCs failed to prime alloantibody responses to subsequent untreated transfusions.

CONCLUSION

Overall, the mechanism of WBC death following UV + R treatment shares some membrane characteristics of early apoptosis but is distinct from classic apoptosis. Despite these differences, UV + R-treated and apoptotic WBCs both offer some protection from alloimmunization.

Reduced MHC alloimmunization and partial tolerance protection with pathogen reduction of whole blood

BACKGROUND

Allogeneic blood transfusion can result in an immune response against major histocompatibility complex (MHC) antigens, potentially complicating future transfusions or transplants. We previously demonstrated that pathogen reduction of platelet-rich plasma (PRP) with riboflavin and ultraviolet light (UV+R) can prevent alloimmunization in mice. A similar pathogen-reduction treatment is currently under development for the treatment of whole blood using riboflavin and a higher dose of UV light. We sought to determine the effectiveness of this treatment in the prevention of alloimmunization.

STUDY DESIGN AND METHODS

BALB/cJ mice were transfused with untreated or UV+R-treated, allogeneic C57Bl/6J whole blood with or without leukoreduction. Mice were evaluated for donor-specific antibodies, ex vivo splenocyte cytokine responses, and changes in the frequency of regulatory T (T_reg ) cells.

RESULTS

UV+R treatment blocked cytokine priming and reduced anti-MHC alloantibody responses to transfused whole blood. Leukoreduction reduced alloantibody levels in both the untreated and UV+R-treated groups. Mice transfused with UV+R-treated whole blood had reduced alloantibody and cytokine responses when subsequently transfused with untreated blood from the same donor type. This reduction in responses was not associated with increased T_reg cells.

CONCLUSIONS

Pathogen reduction of whole blood with UV+R significantly reduces, but does not eliminate, the alloimmune response. Exposure to UV+R-treated whole blood transfusion does appear to induce tolerance to alloantigens, resulting in reduced anti-MHC alloantibody and cytokine responses to subsequent exposures to the same alloantigens. This tolerance does not appear to be driven by an increase in T_reg cells.

Reduced alloimmunization in mice following repeated transfusion with pathogen-reduced platelets

BACKGROUND

Allogeneic transfusion can result in alloimmunization, leading to platelet (PLT) refractoriness and rejection of solid organ transplants. Previously we demonstrated that pathogen reduction using UV light and riboflavin (UV + R) eliminates the immunogenicity of white blood cells (WBCs) in vitro, blocks alloimmunization from transfusion in mice, and results in reduced ex vivo cytokine responses to subsequent untreated transfusions. We sought to determine if repeated transfusion with pathogen-reduced PLT-rich plasma (PRP) would eventually cause breakthrough alloimmunization or enhanced tolerance.

STUDY DESIGN AND METHODS

BALB/cJ mice were transfused weekly for 2, 4, or 8 weeks with C57Bl/6J PRP that was either untreated or pathogen reduced with UV + R and leukoreduced or not. Alloimmunization was determined by measuring donor antibody levels, ex vivo cytokine responses, and 24-hour donor PLT recovery. The role of donor antibodies in PLT refractoriness was also assessed by transfer of diluted immune sera into naïve recipients.

RESULTS

Donor antibody levels increased with the number of transfusions, but levels were significantly reduced using either UV + R or leukoreduction, and combining UV + R and leukoreduction gave the best protection. Priming of ex vivo cytokine responses required WBCs and remained suppressed with repeated UV + R-treated transfusion. PLT recovery was reduced with UV + R in naïve mice, and multiply transfused mice had poor PLT recovery even when antibody levels were relatively low. Approximately 1/100 dose of serum from a multiply transfused mouse was sufficient for complete rejection of donor PLTs.

CONCLUSIONS

Pathogen reduction significantly reduces alloimmunization in repeatedly transfused mice and combined with leukoreduction provides a high level of protection from alloimmunization.

Cyclosporine and Extracorporeal Photopheresis are Equipotent in Treating Severe Atopic Dermatitis: A Randomized Cross-Over Study Comparing Two Efficient Treatment Modalities

Background: Severe atopic dermatitis (AD) is a recurrent and debilitating disease often requiring systemic immunosuppressive treatment. The efficacy of cyclosporine A (CsA) is well proven but potential side effects are concerning. Several reports point at extracorporeal photopheresis (ECP) as an alternative treatment modality with few and mild side effects. However, no direct comparison between CsA and ECP in the treatment of AD has been performed so far.

Objectives: To compare the efficacy of CsA (3 mg/kg/day) and ECP (administered two consecutive days twice a month) in a cohort of patients with severe AD.

Methods: A randomized cross-over study involving twenty patients with severe AD (SCORAD index 41-89) refractory to other treatments. The patients were allocated to a 4-month course of either of the two treatment modalities. Individual relapse periods (2–8 weeks) were interspersed before cross-over to the other treatment modality. Treatment efficacy was evaluated by SCORAD, PRURITUS (VAS-index 0–10), “overall global assessment” and serological biomarkers; sIL-2Rα, sE-selectin, eosinophilocytes, basophilocytes, and sIgE.

Results: 15 patients completed treatment. Both treatments lead to a marked and significant decrease in SCORAD and pruritus index. The average reduction of the SCORAD and pruritus index, respectively was a little higher for ECP treatment compared to CsA treatment; however, the differences did not reach statistical significance. The “overall global assessment” was significantly better in patients who underwent ECP therapy as compared to CsA treatment. None of the biomarkers showed significant changes after either treatment when compared to the initial values.

Conclusion: ECP administered on two consecutive days twice a month to patients with severe AD has similar potency as CsA administered daily in a moderate dose. ECP is a treatment alternative in patients with severe AD that do not tolerate or are refractory to conventional immunosuppressants.

Immune modulation and lack of alloimmunization following transfusion with pathogen-reduced platelets in mice

BACKGROUND

Transfusion of allogeneic blood products can lead to alloimmunization, impacting success of subsequent transfusions and solid organ transplants. Pathogen reduction using riboflavin and ultraviolet B (UVB) light has been shown to eliminate the immunogenicity of white blood cells (WBCs) in vitro through down regulation of surface adhesion molecules, effectively blocking cell-cell conjugation and direct presentation. We sought to determine if this loss of immunogenicity is extended in vivo where indirect presentation of allogeneic antigens can occur.

STUDY DESIGN AND METHODS

BALB/cJ mice were transfused with either untreated or riboflavin and UVB-treated C57Bl/6J platelet-rich plasma (PRP) containing WBCs. Circulating alloantibody and allospecific splenocyte cytokine responses were measured.

RESULTS

Pathogen reduction of allogeneic WBC-enriched PRP using riboflavin and UVB light before transfusion prevented alloimmunization, with a loss of both alloantibody generation and priming of secondary cytokine responses ex vivo. When mice given treated transfusions were subsequently given untreated transfusions, they produced normal levels of alloantibodies but had reduced secondary cytokine responses ex vivo. This immune modulation was antigen specific and was dependent on the presence of WBCs in the treated product.

CONCLUSIONS

UVB plus riboflavin treatment of WBC-enriched PRP effectively blocks alloimmunization and modulates immune responses to subsequent exposures.

UV-induced immunosuppressive and anti-inflammatory actions: mechanisms and clinical applications

The introduction in 1974 of psoralens UVA (PUVA) therapy followed in 1987 by extracorporeal photopheresis (ECP) has launched UV light in medicine field. A significant number of potential mechanisms could be linked to the basic cellular UV action (i.e., DNA damage and subsequent cells apoptosis). Phagocytosis by macrophages and dendritic cells (DCs) leads, through a receptor-mediated process, to their modulation. A state of antigen-specific tolerance is induced by induction of Treg cells, inhibition of DCs, which remain at a an immature state, inhibition of production of the proinflammatory cytokines IL-2, IFN-gamma, TNF-alpha and IL-12, and induction of production of cytokines IL-10, TGF-beta and IL-1Ra. Beside cutaneous T-cell lymphoma, use of ECP remains experimental except for graft-versus-host disease, especially the chronic-resistant form. The sparing action of corticosteroids as described in studies on transplantation deserves further attention.

Understanding loss of donor white blood cell immunogenicity after pathogen reduction: mechanisms of action in ultraviolet illumination and riboflavin treatment

BACKGROUND

Donor white blood cells (WBCs) present in transfusion products can lead to immune sequelae such as production of HLA antibodies or graft-versus-host disease in susceptible transfusion recipients. Eliminating the immunogenicity of blood products may prove to be of clinical benefit, particularly in patients requiring multiple transfusions in whom allosensitization is common. This study examines a method of pathogen reduction based on ultraviolet light illumination in the presence of riboflavin. In addition to pathogens, WBCs treated with this system are affected and fail to stimulate proliferation of allogeneic peripheral blood mononuclear cells (PBMNCs) in vitro.

STUDY DESIGN AND METHODS

This study sought to determine the mechanisms regulating this loss of immunogenicity. Treated cells were examined for surface expression of a number of molecules involved in activation and adhesion, viability, cell-cell conjugation, and ability to stimulate immune responses in allogeneic PBMNCs.

RESULTS

Compared with untreated controls, ultraviolet (UV)-irradiated antigen-presenting cells showed slightly reduced surface expression of HLA Class II and costimulatory molecules and had more significant reductions in surface expression of a number of adhesion molecules. Furthermore, treated cells had a severe defect in cell-cell conjugation. The observed loss of immunogenicity was nearly complete, with UV-irradiated cells stimulating barely measurable interferon-gamma production and no detectable STAT-3, STAT-5, or CD3-epsilon phosphorylation in allospecific primed T cells.

CONCLUSION

These results suggest that defective cell-cell adhesion prevents UV-irradiated cells from inducing T-cell activation.

In vitro experiments demonstrate that monocytes and dendritic cells are rendered apoptotic by extracorporeal photochemotherapy, but exhibit unaffected surviving and maturing capacity after 30 Gy gamma irradiation

Extracorporeal photochemotherapy (ECP) has been shown to induce apoptosis in lymphocytes. Until recently the prevailing opinion has been that the monocytes were mainly not affected by this treatment. This study has investigated the effect of ECP and gamma irradiation on monocytes and immature dendritic cells (DC) in vitro and followed the ability of the cells to differentiate and survive post treatment. ECP induced apoptosis in lymphocytes, monocytes and immature DC within 72 h following treatment, in contrast to 30 Gy gamma irradiation, which seemed mainly to affect lymphocytes. The minority of the surviving ECP-treated monocytes presented a reduced ability to differentiate into immature DC within this time frame. We also demonstrated that immature DC after ECP-treatment lost their normal ability to mature on stimulation with lipopolysaccharide. As monocytes and immature DC seem to have a reduced ability to differentiate after ECP-treatment, it is suggested that the therapeutic effect of ECP is caused by in vivo effects of reinfused apoptotic cells, rather than by infusion of monocytes induced to differentiate into immature DC.

Apoptosis: A target for potentiation of UV-induced IL-1Ra synthesis by IVIg

IL-1Ra prevents IL-1 induced inflammatory signalling, a mechanism potentially important for several pathological conditions characterized by inflammation. When administered as a drug in the recombinant form, it displays a protective effect towards them. We postulated that this action could also be achieved by pharmacological activation of endogenous IL-1Ra production. We previously showed that photochemotherapy and UV-light increased monocyte/macrophages IL-1Ra secretion. A similar effect has been shown for IVIg. The aim of this study was to define optimal in vitro conditions for induction of IL-1Ra secretion. As both agents induce lymphocytes apoptosis, we focused our analysis on the influence of IVIg on UV-induced-IL-1Ra production on this mechanism. After overnight preincubation at 37 degrees C, UV-irradiated PBL mixed with two IVIg concentrations (1 and 25 mg/ml) were cocultured with autologous PBMC. Apoptosis was measured by annexin V/PI. IL-1Ra secretion was evaluated by RT-PCR and Luminex microbead array assay. A significant additive dose-dependent influence of IVIg (+85%; p=0.0005) on UV-induced IL-1Ra secretion, involved both Fc-receptor activation at a low dose (1 mg/ml) and a potent apoptotic action on PBL reinforcing the UV effect at high concentrations (25 mg/ml). We conclude that lymphocyte apoptosis represents an important pathway contributing to enhancement of UV-induced monocyte/macrophages IL-1Ra production by IVIg and that these findings should be considered when evaluating in vivo protocols for photochemotherapy and IVIg treatment, in hope of improving efficacy.

Extracorporeal photochemotherapy in patients with cutaneous T-cell lymphoma: is clinical response predictable?

BACKGROUND

Extracorporeal photochemotherapy (ECP) has been accepted as a standard therapy in cutaneous T-cell lymphomas (CTCL), a category of lymphomas mainly resistant to conventional therapies. Approximately one half of patients demonstrate a reduction in skin affliction by at least 50% within 12 months of therapy and are categorized as responders to ECP. Predictive criteria for selecting patients who will respond to ECP are lacking. Such criteria would however, be of great benefit.

OBJECTIVES

This study compared T-cell clonality and serum levels of soluble interleukin-2 receptor (sIL-2R), lactate dehydrogenase (LD), neopterin, beta2-microglobulin (beta(2)-M) and granzyme B in CTCL patients in order to evaluate their potential usefulness as predictive markers.

PATIENTS/METHODS

Serum and T lymphocytes obtained from 16 patients with CTCL receiving ECP treatment were evaluated in an open retrospective study.

RESULTS

We found no evident correlation between detected T-cell clonality and response to ECP. The non-responding group had on average a higher level of serum sIL-2R. This difference was significant after 6 and 12 months of therapy, but not pretreatment. An individual reduction in serum sIL-2R, neopterin and beta(2)-M during a 6-month course of ECP was well correlated to clinical remission.

CONCLUSIONS

Seven out of 16 patients were classified as responders. Neither T-cell clonality nor any of the serum markers assessed pretreatment could reliably predict the response to ECP treatment. However, the individual relative changes in sIL-2R, neopterin and beta(2)-M during 6 months of ECP treatment coherently displayed correlation to the clinical response, as assessed after 12 months of ECP treatment.

Anti-inflammatory effects of UV-irradiated lymphocytes: induction of IL-1Ra upon phagocytosis by monocyte/macrophages

One of the mechanisms proposed to explain immunomodulatory actions of ultraviolet light (UV) is production of endogenous anti-inflammatory cytokines. The purpose of the present study is to evaluate how UV light affects the production of IL-10 and IL-1Ra and to provide insight as to the role of phagocytosis of apoptotic lymphocytes in this process. Cytokine production was evaluated in a coculture system consisting in UV-treated lymphocytes in the presence of autologous PBMC. The impact of phagocytosis was tested by two blocking agents cytochalasin E and anti-CD36 mAb. The apoptotic process affecting irradiated lymphocytes was progressive, culminating at 48 h. To achieve significant cytokine production, irradiated lymphocytes were incubated overnight at 37 degrees C. Coculture of apoptotic lymphocytes with autologous PBMC resulted in a significant increase of IL-1Ra mRNA (+340%; P = 0.001) and protein (+72%; P = 0.001) production. This synthesis was blocked by cytochalasin E but upregulated by CD36 receptor cross-linking. Our study shows that UV light induces lymphocyte apoptosis followed by its phagocytosis by monocyte/macrophages, a step that preferentially activates IL-1Ra.

Current management strategies for cutaneous T-cell lymphoma

Cutaneous T-Cell Lymphoma is a group of lymphomas characterized by a malignant proliferation of skin homing T cells. Prognosis is generally good and treatment is based on the stage of the disease with the goal of inducing remission. Patients with disease limited to the skin in the form of patches and plaques respond best to "skin directed therapy" with topical agents including corticosteroids, nitrogen mustard, carmustine, bexarotene gel, as well as phototherapy with ultraviolet B light, PUVA, or photodynamic therapy. Tazarotene and imiquimod show potential in the treatment of early CTCL. Patients with disease resistant to treatment or with advanced disease require more aggressive therapy in the form of total skin electron beam radiation, biologic response modifiers including interferon alpha, bexarotene, denileukin diftitox, extracorporeal photochemotherapy or combination therapy. The use of chemotherapy is used primarily for palliation. Allogeneic hematopoetic stem cell transplantation may represent a successful treatment for treatment resistant disease.

Increased production of interleukin-10 and interleukin-1 receptor antagonist after extracorporeal photochemotherapy in chronic graft-versus-host disease

BACKGROUND

Mechanisms of action of extracorporeal photochemotherapy (ECP) in graft-versus-host disease are incompletely understood. It has been proposed that phagocytosis of apoptotic bodies by monocytes and macrophages induces their activation, a process that increases production of immunosuppressive cytokines. We analyzed apoptosis and cytokine secretion in an autologous coculture system combining peripheral blood lymphocytes (PBL) obtained after ex vivo ECP treatment and nonirradiated peripheral blood mononuclear cells (PBMC).

METHODS

We studied 11 leukapheresis products treated by ECP from six patients with resistant limited or extensive chronic graft-versus-host disease. Purified PBL obtained by monocyte depletion of the buffy coat from leukapheresis products were mixed with nonirradiated PBMC. Nonirradiated PBL were used as control. Cytokine production was tested at the mRNA level by real-time reverse transcriptase-polymerase chain reaction for interleukin (IL)-10, IL-1 receptor antagonist (IL-1Ra), IL-1beta, tumor necrosis factor-alpha, and IL-12p40.

RESULTS

Morphologic analysis and flow cytometry displayed important lymphocyte apoptotic features culminating at 24 to 48 hr. Coculture of patient's PBMC with ultraviolet-irradiated PBL as compared with nonirradiated PBL resulted in significant increase of IL-10 mRNA (3418+/-1015 versus 10596+/-3402 mRNA copy numbers; P=0.001) and IL-1Ra mRNA (23890+/-6166 versus 41767+/-10181 mRNA copy numbers; P=0.001). Incubation with a neutralizing anti-IL-10 monoclonal antibody resulted in a marked decrease of IL-1Ra mRNA levels.

CONCLUSION

Our findings are consistent with the fact that ECP modifies patient's autologous lymphocytes by inducing a process of apoptosis that activates monocytes and macrophages, leading to increased synthesis of IL-10 and IL-1Ra mRNAs. The induction of this latter mediator is dependent on IL-10.

Extracorporeal photochemotherapy--the Columbia Presbyterian experience

BACKGROUND

Cutaneous T Cell Lymphoma (CTCL) is a lymphoma of skin homing usually CD4 + lymphocytes. There are numerous treatments available both for the early as well as the more advanced stages of the disease. Extracorporeal photochemotherapy is a well-accepted form of treating CTCL. The purpose of our study was to review the experience of treating 20 CTCL patients with extracorporeal photochemotherapy (ECP) at Columbia Presbyterian Medical Center over a seven-year period.

METHODS

The study was conducted as a retrospective chart review of these 20 patients. Summarized demographic characteristics included age at diagnosis, gender, and race. We analyzed the overall response by categorizing patients as having complete response, partial response, stable disease, and progressive disease. We also analysed the predictive value for three factors: peripheral blood CD4 : CD8 (< 10, > 10), LDH level (normal, elevated), and erythrodermic status (erythrodermic or nonerythrodermic). The potential prognostic variables were evaluated for linear association with response using Mantel-Haenszel chi-square tests. All statistical tests were two-sided with alpha = 0.05. The tests were considered to be exploratory and no adjustments for multiple testing were made.

RESULTS

There was a significant linear association between response and CD4 : CD8. Patients with a ratio < 10 were more likely to respond than patients with a ratio > 10. There was a marginally significant linear association between response and LDH level. Patients whose LDH was not elevated at the start of treatment, tended to have a better response to ECP compared to patients with an elevated LDH. There was a suggestion of an association between erythroderma and response although this was not statistically significant. The majority of patients with erythroderma were responders compared to the majority of non-erythrodermic patients who were non-responders. The treatment was well tolerated with minimal side-effects.

CONCLUSION

Apparent predictors of good response to ECP include erythroderma, a relatively low (closer to normal) peripheral CD4 : CD8, and a normal LDH. This report confirms reports from other institutions indicating that CTCL patients who are erythrodermic with a relatively intact immune system are optimal candidates for ECP.