Photopheresis in the treatment of autoimmune disease: experience with pemphigus vulgaris and systemic sclerosis

Extracorporeal photopheresis as a therapy for autoimmune diseases

Systemic autoimmune diseases (AID) have multiorgan, heterogeneous clinical presentations and are characterized by dysregulation of the immune system, immunodeficiency, irreversible organ damage and increased morbidity and mortality. Preventing or decreasing flares of AID correlate with durable disease control, significant reduction of inflammation and prevention of disability or therapy-related toxicity. There is an urgent need for better treatment of severe, therapy-refractory AID. Extracorporeal photopheresis (ECP) is a cell-based immunomodulatory treatment which has been extensively used in variety of autoimmune disorders for the last two decades. ECP treatment is FDA approved for the treatment of cutaneous T-cell lymphoma (CTCL) with particularly promising results seen in graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (HCT). Prolonged therapy is safe, well tolerated and allows reduction of systemic immunosuppression in therapy-refractory patients. Both clinical and experimental evidence suggest that ECP mechanism of action is characterized by apoptosis and phagocytosis of activated cells by antigen-presenting cells (APC), secretion of anti-inflammatory cytokines and stimulation of regulatory T cells (Tregs). The focus of this paper is to review the current evidence of ECP use in the treatment of AID. Here, we summarize the experience of nine major AID from 65 published reports. The key findings demonstrate substantial evidence of ECP feasibility, safety and in some AID also promising efficacy. However, the role of ECP in AID therapy is not established as most published studies are retrospective with limited number of patients and the trials are small or poorly standardized. The available data support future investigations of ECP as a therapeutic modality for the treatment of AID in well-designed prospective clinical studies. J

Pyrrolo[2,3-h]quinolinones: a new ring system with potent photoantiproliferative activity

A new class of compounds, the pyrrolo[2,3-h]quinolin-2-ones, nitrogen isosters of the angular furocoumarin Angelicin, was synthesized with the aim of obtaining new photochemotherapeutic agents with increased antiproliferative activity and lower undesired toxic effects than the lead compound. Two synthetic pathways were approached to allow the isolation both of the dihydroderivatives 10-17 and of the aromatic ring system 23. Compounds 10-17 showed a remarkable phototoxicity and a great UVA dose dependence reaching IC(50) values at submicromolar level. Intracellular localization of these compounds has been evaluated by means of fluorescence microscopy using tetramethylrhodamine methyl ester and acridine orange, which are specific fluorescent probes for mitochondria and lysosomes, respectively. A weak co-staining was observed with mitochondrial stain, whereas a specific localization in lysosomes was observed. Studies directed to elucidate the mode of action of this series of compounds revealed that they do not intercalate with DNA and do not induce photodamage to the macromolecule. On the contrary, they induce significative photodamage to lipids and proteins.

Treatment of pemphigus vulgaris: current and emerging options

BACKGROUND

Pemphigus vulgaris is a rare, chronic, autoimmune mucocutaneous blistering disease. The disease can progress to involve the skin and multiple mucosae. Pemphigus vulgaris can be associated with a high morbidity and significant mortality rate. Treatment of the condition can be challenging. Conventional therapy primarily consists of systemic corticosteroids and immunosuppressant agents. In some patients with pemphigus vulgaris, these agents fail to provide an effective clinical response or have significant adverse effects.

METHODS

We evaluated data on 792 patients with pemphigus vulgaris retrieved from PubMed, covering the period 1973-2004. Only patients reported in the English literature were included in this review. Recently, several new therapeutic agents and treatment modalities have been described for the treatment of patients with pemphigus vulgaris. Some therapeutic agents that were used in the past and abandoned have recently regained favor. This review focuses on the therapeutic uses of dapsone, methotrexate, mycophenolate mofetil, chlorambucil, dexamethasone-cyclophosphamide pulse therapy, immunoablative therapy with cyclophosphamide, plasmapheresis, and extracorporeal photochemotherapy. Newer agents, such as intravenous immunoglobulin (IVIg) therapy and rituximab (an anti-CD20 chimeric monoclonal antibody), are also discussed.

RESULTS AND CONCLUSIONS

Among the oral agents, dapsone may be considered a first-line agent. This is primarily because the risk of potentially fatal adverse effects with this drug is lower than that associated with other available chemotherapeutic agents. In patients who are refractory to oral agents, alternative treatments have been used to prevent further disease progression. Recently, the use of IVIg therapy, with a defined protocol, has been reported to be beneficial. This therapy is promising since it may allow for discontinuation of all other therapies and is safe. The adverse effects from IVIg therapy are minimal. Furthermore, compared with other therapies, it provides a better quality of life.

Psoralen and UVA light: an in vitro investigation of multiple immunological mechanisms underlying the immunosuppression induction in allograft rejection

Photopheresis (ECP) is a novel immunomodulatory therapy effectively used to treat several T-cell-mediated diseases and to reverse allograft rejection after organ transplantation. It consists of infusion of UVA-irradiated autologous leukocytes collected by apheresis and extracorporeally incubated with 8-methoxypsoralen (8-MOP). In this study we explored the potential immunological events for therapeutic efficacy of photopheresis in preventing allograft rejection by evaluating in vitro the combined effects of 8-MOP and UVA (PUVA) on multiple immunological parameters, such as induction of apoptosis, production of soluble mediators, and expression of cell antigens. Peripheral blood mononuclear cells (PBMCs) obtained from healthy subjects were treated with 8-MOP and UVA at the same doses as those clinically used in ECP. We demonstrate that PUVA treatment induced leukocyte hyporesponsiveness and a decrease in expression of co-stimulatory and adhesion molecules as well as of cytokine levels. Additionally, PUVA treatment induced apoptosis in both mononuclear cells (possibly through the Fas/FasL system and/or the CD38 pathway) and purified monocytes. In conclusion, our work focuses attention on the initial phase of immune response and identifies some new targets of therapy (e.g., costimulatory molecules) able to trigger final effects underlying therapeutic efficacy of photopheresis.

Treatment of systemic sclerosis

Systemic sclerosis is an extremely variable disease in its manifestations and consequently, treatment needs to be individualized depending on the specific problems that each patient has. Limited scleroderma patients have a prolonged duration of Raynaud's phenomenon and puffy fingers before they develop any skin thickening, digital ulcers or gastrointestinal symptoms. They are likely to present with all the classic manifestations of scleroderma. Diffuse scleroderma patients have a much more acute systemic onset with marked whole hand swelling and may initially have only subtle skin thickening. A good understanding of the differences between the natural history of limited and diffuse scleroderma will enable the physician to treat present problems and anticipate future ones more effectively. One should determine which major subset and organ systems are involved before deciding on the appropriate therapy. Advances in organ-specific therapy, particularly calcium channel antagonists in Raynaud's phenomenon, proton pump inhibitors in esophageal reflux, intravenous iloprost and endothelin receptor antagonists in pulmonary hypertension, and ACE inhibitors in renal crisis, have decreased morbidity and mortality in patients with scleroderma. Studies of aggressive therapies to prevent or improve pulmonary fibrosis are in progress. Further clinical experience in wound healing, gastrointestinal malabsorption and physical therapy for loss of motion has helped patients to have a more comfortable life. In recent years, a significant number of controlled clinical trials have been performed and there has been improved understanding of the best way to perform studies and of which patients are most likely to respond to therapy. Penicillamine, methotrexate, photopheresis, relaxin, interferons, and cyclosporine have all been studied in controlled trials with variable outcomes. Although an overall remittive therapy has not yet been determined, new, potentially useful agents are being investigated.

Extracorporeal photochemotherapy does not suppress T- or B-cell responses to novel or recall antigens

BACKGROUND

Extracorporeal photopheresis (ExP) is an effective therapy for several conditions including cutaneous T-cell lymphoma, scleroderma, and allograft rejection. Experimental animal models suggest that ExP may induce antigen-specific immunosuppression.

OBJECTIVE

Our purpose was to determine the effect of photopheresis on humoral and cell-mediated immunity in human subjects.

METHODS

Recall and primary immune responses of patients with scleroderma receiving monthly ExP treatments were assessed by delayed type hypersensitivity skin tests, T-cell proliferative responses after immunizations with tetanus toxoid and keyhole limpet hemocyanin, and serum antibody titers against common viral pathogens.

RESULTS

After 6 months of ExP, viral antibody titers and delayed type hypersensitivity responses were not significantly different from baseline values in all 7 patients tested. T-cell responses to tetanus toxoid remained normal in 3 of 3 patients tested for a minimum of 6 months after booster immunization. Immunization with the protein antigen keyhole limpet hemocyanin after initiation of ExP therapy resulted in sustained T-cell proliferative responses up to 6 months in 3 of 3 patients.

CONCLUSION

These results, along with the observation of no increased incidence of opportunistic infections or neoplasms, suggest that ExP is not broadly immunosuppressive and does not prevent primary responses to vaccination or other antigenic challenges.

Treatment of autoimmune blistering diseases

The treatment of autoimmune blistering diseases remains therapeutically challenging. Significant improvement in the management of autoimmune bullous diseases has occurred as a consequence of improvements in our ability to predict, monitor, and treat the deleterious effects associated with the drugs used to treat these conditions and the introduction of new agents with lower toxicity. Examples include improvements in monitoring and preventing osteoporosis in patients on long-term systemic corticosteroids, the detection of those at risk for azathioprine toxicity bowing to low thiopurine methyltransferase activity, and the addition of agents such as mycophenolate mofetil and IVIG to our therapeutic armamentarium. These advances offer the promise of improved disease control with fewer side-effects and long-term toxicity for our patients.

Normal oxidative activity and chemotaxis of circulating neutrophils in patients treated with photopheresis

In photopheresis peripheral leukocytes are exposed to photoactivated 8-methoxypsoralen in an extra-corporeal flow system. The present study was performed to characterize the effect of photopheresis upon the function of peripheral circulating neutrophils. Superoxide generating capacity and chemotactic ability of peripheral circulating neutrophils were tested in seven patients immediately before and after treatment with photopheresis. Superoxide generation stimulated by phorbol-12-myristate-13-acetate and N-formyl-methionyl-leucyl-phenylalanine (fMLP) and fMLP-induced chemotaxis were found not to be influenced by photopheresis. We conclude that circulating neutrophils obtained from patients treated with photopheresis possess normal superoxide-generating capacity and chemotactic ability.