Photopheresis--extracorporeal irradiation of 8-MOP containing blood--a new therapeutic modality

Pemphigus autoimmunity: hypotheses and realities

The goal of contemporary research in pemphigus vulgaris and pemphigus foliaceus is to achieve and maintain clinical remission without corticosteroids. Recent advances of knowledge on pemphigus autoimmunity scrutinize old dogmas, resolve controversies, and open novel perspectives for treatment. Elucidation of intimate mechanisms of keratinocyte detachment and death in pemphigus has challenged the monopathogenic explanation of disease immunopathology. Over 50 organ-specific and non-organ-specific antigens can be targeted by pemphigus autoimmunity, including desmosomal cadherins and other adhesion molecules, PERP cholinergic and other cell membrane (CM) receptors, and mitochondrial proteins. The initial insult is sustained by the autoantibodies to the cell membrane receptor antigens triggering the intracellular signaling by Src, epidermal growth factor receptor kinase, protein kinases A and C, phospholipase C, mTOR, p38 MAPK, JNK, other tyrosine kinases, and calmodulin that cause basal cell shrinkage and ripping desmosomes off the CM. Autoantibodies synergize with effectors of apoptotic and oncotic pathways, serine proteases, and inflammatory cytokines to overcome the natural resistance and activate the cell death program in keratinocytes. The process of keratinocyte shrinkage/detachment and death via apoptosis/oncosis has been termed apoptolysis to emphasize that it is triggered by the same signal effectors and mediated by the same cell death enzymes. The natural course of pemphigus has improved due to a substantial progress in developing of the steroid-sparing therapies combining the immunosuppressive and direct anti-acantholytic effects. Further elucidation of the molecular mechanisms mediating immune dysregulation and apoptolysis in pemphigus should improve our understanding of disease pathogenesis and facilitate development of steroid-free treatment of patients.

Current and emerging treatment strategies for cutaneous T-cell lymphoma

Cutaneous T-cell lymphomas (CTCLs) are a rare group of mature T-cell lymphomas presenting primarily in the skin. The most common subtypes of CTCL are mycosis fungoides and its leukaemic variant Sézary's syndrome. Patients with early-stage disease frequently have an indolent clinical course; however, those with advanced stages have a shortened survival. For the treating physician, the question of how to choose a particular therapy in the management of CTCL is important. These diseases span the disciplines of dermatology, medical oncology and radiation oncology. Other than an allogeneic stem cell transplant, there are no curative therapies for this disease. Hence, many treatment modalities need to be offered to the patient over the course of their life. An accepted treatment approach has been to delay traditional chemotherapy, which can cause excessive toxicity without durable benefit. More conservative treatment strategies in the initial management of CTCL have led to the development of newer biological and targeted therapies. These therapies include biological immune enhancers such as interferon alpha and extracorporeal photopheresis that exert their effect by stimulating an immune response to the tumour cells. Retinoids such as bexarotene have been shown to be effective and well tolerated with predictable adverse effects. The fusion toxin denileukin diftitox targets the interleukin-2 receptor expressed on malignant T cells. Histone deacetylase inhibitors such as vorinostat and romidepsin (depsipeptide) may reverse the epigenetic states associated with cancer. Forodesine is a novel inhibitor of purine nucleoside phosphorylase and leads to apoptosis of malignant T cells. Pralatrexate is a novel targeted antifolate that targets the reduced folate carrier in cancer cells. Lastly, systemic chemotherapy including transplantation is used when rapid disease control is needed or if all other biological therapies have failed. As response rates to most of the biological agents used to treat CTCL are 25-30%, it is also reasonable to consider clinical trials with novel agents if one or two front-line therapies have failed, especially before considering chemotherapy. CTCL is largely an incurable disease with significant morbidity and more active agents are needed.

Extracorporeal photochemoimmunotherapy in cutaneous T-cell lymphoma

Extracorporeal photochemotherapy was originally conceived for the treatment of cutaneous T-cell lymphoma (CTCL) and as well as other T-cell mediated diseases. Evidence collected in the past 17 years has demonstrated that this treatment modality can have a very significant effect on the course of a subset of CTCL patients. The evidence available is positive but for a variety of reasons has been controversial within the medical community. A number of very well-designed multi-center trials which have been lacking since the first publication by Edelson et al. are being carried out so that hopefully a number of open questions will be resolved with greater clarity in the coming years. The fact remains that this innovative approach for the treatment of CTCL and T-cell mediated diseases has certainly opened new avenues of therapy and thought in photoimmunology and photomedicine. Clearly the very low side effect profile of this therapy has made it more attractive than the chemotherapeutic and immunosuppressive substances that are presently available or in experimental protocols. If and when the mechanisms of action are fully understood and appropriate studies investigating different treatment schedules and different combination therapies and modifications of its present form are performed the place of photopheresis in the therapeutics of CTCL as well as other T-cell mediated diseases and oncology will be better placed.

Long-term follow-up of patients with cutaneous T-cell lymphoma treated with extracorporeal photochemotherapy

BACKGROUND

Few studies have assessed the long-term outcome of patients with cutaneous T-cell lymphoma (CTCL) treated with extracorporeal photochemotherapy (ECP).

OBJECTIVE

Our objective was to assess the efficacy, safety, and survival of a cohort of patients with refractory T-cell lymphoma in various stages of cutaneous involvement who were treated with ECP.

METHODS

Twenty patients who had received at least 6 months of ECP between September 1988 and April 1991 were reevaluated and the data analyzed statistically to obtain outcome data through December 1995.

RESULTS

A complete response (disappearance of all lesions) was obtained in five patients (25%) and a partial response (disappearance of at least 50% of lesions) in five patients (25%). Of the 10 responders, seven (70%) were weaned from ECP. Two of seven patients had a relapse. Ten patients (50%) showed no response to ECP. No statistically significant differences between responders and nonresponders were found with respect to demographic, clinical, or laboratory variables. Seven patients died of causes directly related to CTCL and two patients died of unrelated causes. Median survival time for the entire cohort was 96 months (range, 16 to 152 months). An assessment of early response after 6 to 8 months of ECP had a sensitivity of 100% and a specificity of 90% for predicting long-term (> 4 years) outcome. Adverse effects were minimal.

CONCLUSION

ECP is a safe effective alternative therapy for CTCL that is refractory to other therapies; it can induce a long-term, disease-free remission in a minority of patients. Response in the first 6 to 8 months of treatment predicts long-term outcome.

Extracorporeal photopheresis--a new approach for the treatment of cutaneous T cell lymphomas

Extracorporeal photochemotherapy (extracorporeal photopheresis, ECP) is going to become a new alternative in the treatment of cutaneous T cell lymphomas (CTCL), autoimmune disorders, and transplant rejections. After the first promising results in the treatment of CTCL reported in 1987 by Edelson et al. increasing numbers of CTCL patients in a growing number of ECP centers throughout the United States, Europe, and Japan have been successfully treated. Today, it seems that in particular Sézary's syndrome and the erythrodermic variant of mycosis fungoides (MF) respond very well to ECP. Compared to historical controls of MF with lymph node involvement, the median survival of the ECP-treated patients increased from 30 months to up to 60 months. It is our experience that the tumor stage of MF, however, cannot be treated with ECP alone, but is successfully controlled by combination regimens, for example with recombinant interferon alpha. CTCL patients heavily pretreated by polychemotherapy and severe endogenous or iatrogenic immunsuppression do not respond sufficiently and are not good candidates for ECP. The adverse reactions under ECP are well controlled and very low in number. In particular, general immunosuppression by ECP has not been reported so far.

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.

Extracorporeal photopheresis for the treatment of cutaneous T-cell lymphoma

BACKGROUND

Many regimens are used for cutaneous T-cell lymphoma (CTCL), but with advanced disease response rates and patient survival are not adequate with any current therapy. Recently extracorporeal photochemotherapy (ECP) was proposed as an alternative therapy.

OBJECTIVE

Our purpose is to present the results of ECP in patients with CTCL refractory to other treatments.

METHODS

Patients with CTCL received ECP at 3- to 5-week intervals for at least 6 months. All patients except one were in stage T2 (patch/plaque) or higher. Eight patients had extracutaneous disease involving lymph nodes (six patients), bone marrow (five), or Sézary cells (six). The interval between initial symptoms and diagnosis was 5.9 +/- 1.9 years (mean +/- standard error of the mean) and the interval between diagnosis and ECP was 2.2 +/- 0.4 years.

RESULTS

A complete response (disappearance of all lesions) was obtained in five patients (25%) and a partial response (disappearance of at least 50% of lesions) in six patients (30%). Four patients (20%) showed stabilization of their disease and five progressed (25%). The only variable that predicted responders versus nonresponders was the number of ECP sessions (p < 0.05 by multivariate logistic regression). In contrast, no separate beneficial effect of adjunctive chemotherapy (p > 0.5) or electron beam therapy (p > 0.1) was found.

CONCLUSION

Long-term ECP may be an effective alternative treatment for CTCL refractory to other therapies and is likely to be even more useful when combined with other modalities.

Experimental treatment of chronic lymphocytic leukemia with extracorporeal photochemotherapy. Initial observations

Based on the encouraging results obtained with extracorporeal photochemotherapy (EP) in the treatment of the exfoliative erythrodermic form of cutaneous T-cell lymphoma (CTCL), leukemic form, as well as other T-cell-mediated diseases we evaluated the therapeutic potential of EP in patients with chronic lymphocytic leukemia (B-CLL). Three patients with B-CLL were treated for a period of 1 year. Two patients showed stabilization of disease, as demonstrated by reduction in their peripheral white blood cell count, with one patient showing lymph-node resolution. A third patient with significant intolerance to previous chemotherapy did not respond within the observed period. No significant side effects of EP were observed. Our observations suggest that EP may have a positive effect on the course of B-CLL in selected patients. Additional clinical trials are warranted to further define the role of EP alone or in combination therapy in the management of B-CLL.