Treatment of cutaneous T-cell lymphoma by extracorporeal photochemotherapy. Preliminary results

Photopheresis for rheumatoid arthritis

For rheumatoid arthritis, an effective therapy with minimal toxicity would be welcome. In a six-month pilot study of seven patients with a variety of presentations and previous treatments, we tested a therapy involving the extracorporeal photoactivation of biologically inert methoxsalen (8-methoxypsoralen) by ultraviolet A energy to a form that covalently cross-links lymphocyte DNA; the injured cells are returned to the patient. Prior experimental studies had indicated that this regimen produces an immune reaction against antigens on treated T Cells, and a clinical trial in cutaneous T cell lymphoma had been successful. The current patients were treated on two successive days monthly (or, later on, biweekly). Between 12 and 16 weeks of therapy there appeared to be a breakpoint after which joint counts and joint scores of four patients began to improve. In three of them, these measures eventually diminished by mean values of 71% and 80%, respectively, of their baseline values, along with variable improvement in less direct indicators of clinical response. The joints of the fourth patient improved modestly (by 33% and 59%, respectively, of baselines) but he required alternative therapy, and those of the remaining three patients did not improve. Mean slopes for the joint counts were significantly different from zero after the apparent breakpoint (but not before), whether one examined the four apparent responders (p = 0.01) or the entire group of seven (p = 0.01). After completion of therapy, there was also a delay, of two to three months, in the clinical deterioration of those who had improved. There was only one mechanical adverse effect--a single episode of transient hypotension in 102 treatment sessions--and no toxic ones. This preliminary study suggests that extracorporeal photochemotherapy may be effective at least in the short term in certain patients with rheumatoid arthritis, with less apparent toxicity than that of any of the drugs currently used for this disorder. It deserves further evaluation.

Photopheresis: a clinically relevant immunobiologic response modifier

Photopheresis, the process by which peripheral blood is exposed in an extracorporeal flow system to photoactivated 8-methoxypsoralen (8-MOP), is an effective new treatment for certain disorders caused by aberrant T lymphocytes. It has become a standard therapy for advanced cutaneous T cell lymphoma and shows promise in the treatment of four autoimmune disorders (pemphigus vulgaris, the progressive systemic sclerosis form of scleroderma, rheumatoid arthritis, systemic lupus erythematosus) and in reversal of immunologic rejection of transplanted organs. Positive immunologic alterations observed in patients with AIDS-related complex merit further investigation, and preliminary trials in the management of patients with multiple sclerosis, myasthenia gravis and autoimmune insulin-dependent diabetes mellitus have recently been initiated. The inability of the treatment to meaningfully alter the course of the B cell malignancy, chronic lymphocytic leukemia, suggests that B cell proliferations, at least those involving malignant cells, may be more resistant to this treatment. The mechanism of action of photopheresis is likely to be multifaceted, but at least in experimental systems appears to involve an immunization against the pathogenic T cells, in a highly specific manner. Photoactivated 8-MOP initiates a cascade of cellular events by forming covalent photoadducts with nuclear DNA, with cell surface molecules and possibly with other cytoplasmic components of the ultraviolet exposed leukocytes. For reasons not yet clear, exposure of populations of T cells containing expanding a clone(s) of pathogenic T cells to photoactivated 8-MOP alters these cells so that their reinfusion induces a therapeutically significant immunologic reaction that targets unirradiated T cells of the same pathogenic clone(s). It is suggested that the specificity of the induced immunologic reaction may result, in sequence, from the exquisitely titratable damage that 8-MOP inflicts upon cells of the pathogenic clone(s), the return of these cells to an immunocompetent individual, the removal of the photo-damaged cells from the blood by the reticuloendothelial system and the preferential induction of an immune response against cells of the pathologically expanded clone(s).

Antigen-specific tolerance induced by autoimmunization with photoinactivated syngeneic effector cells

Development of a protocol that could invoke specific suppression of an undesired immune response, while sparing normal immune competence, would be of great clinical value. This report demonstrates that multiple infusions of splenocytes sensitized in vivo to sheep red blood cells (SRBC) and photoinactivated in vitro with 8-methoxypsoralen and ultraviolet A light can render a syngeneic recipient selectively unresponsive to subsequent challenge with this antigen. Mice treated in this fashion did not develop a T cell-mediated delayed type hypersensitivity (DTH) reaction to SRBC. In contrast, control mice exposed to nonimmune splenocytes pretreated in an identical manner developed a normal DTH response to SRBC, thereby demonstrating that drug and light in the absence of effector T cells were not suppressive. Inhibition of the DTH response was antigen specific, since animals rendered unresponsive to SRBC developed a normal DTH response to chicken red blood cells. Cell transfer experiments demonstrated that unprimed recipients of splenocytes from mice rendered unresponsive to SRBC could not mount a DTH reaction when challenged. Moreover, this procedure can also suppress established immunity to that antigen. The use of photoinactivated syngeneic antigen-reactive effector cells as immunosuppression agents suggests that this method may be clinically useful in inhibiting pathogenic antigen-specific immunologic reactions.

Autoregulation of the immune response in autoimmune disease and cardiac transplantation by photoinactivated autologous lymphocytes

These studies demonstrate that photochemotherapy can be successfully evaluated in animal models. The therapy mediates specific suppression of immune responses and appears to operate at the level of the effector T cells. Future studies will focus on isolation and characterization of the host response to photochemotherapy. The extention of this form of therapy to conditions mediated by dysfunctional regulation of effector T cells is already in progress in clinical trials of cardiac allograft transplantation and autoimmune disease. The results of these trials will provide more evidence on the role of this form of therapy in autoregulation of the immune response.

Viral-specific immunization in AIDS-related complex by photopheresis

The potential for therapeutic intervention in 7 patients with AIDS-related complex (ARC) was evaluated through the use of photopheresis. The rationale for the study was based on: 1. the demonstration that psoralen and UVA could inactivate HIV/virus in vitro; 2. CD4 cells are the primary target population effected by HIV and photopheresis; and 3. reinfusion of inactivated virus and cell-associated virus might serve to engender an immune response. Preliminary results in 7 patients with ARC over 6 to 18 months revealed a virus-specific response with an elevation of HIV antibodies, while EBV and CMV titers remained unchanged. The immunologic results revealed an increase in the CD8 lymphocyte population, stable activation markers (B2 microglobulin neopterin), a decrease in p24 antigen titers and inability to culture HIV virus in 3 patients. All of these results were in the context of a stable or increasing CD4+ percent. Six patients did not reveal a generalized inhibition of other immune responses as demonstrated by recovery of DTH. In addition, the resolution of lymphadenopathy, night sweats, fever and weight loss, paralleled the immunologic response.

Inhibition of antiskin allograft immunity induced by infusions with photoinactivated effector T lymphocytes (PET cells). Is in vivo cell transferrable?

We previously reported producing donor-specific tolerance to alloantigens by intravenous exposure to pretreated antidonor T cells. The current study extends that work by adoptively transferring the donor-specific tolerance into naive syngeneic recipients. Eight days after BALB/c mice received histoincompatible CBA/j skin grafts, their splenocytes which included an expanded population of cells mediating rejection were treated with 100 ng/ml 8-methoxypsoralen (8-MOP) photoactivated by 1 Joule/cm2 of ultraviolet A (UVA) light prior to infusion into naive BALB/c recipients. Whereas 8-MOP itself is biologically inert, photoactivated 8-MOP crosslinks DNA by covalently binding to pyrimidine bases. Recipient BALB/c mice which had been previously demonstrated to be hyporesponsive to CBA/j alloantigens in mixed leukocyte culture (MLC), cytotoxicity (CTL) and in vivo delayed type hypersensitivity (DTH) assays were the donors of spleen cells for the adoptive transfer experiments. Fifty to one hundred million viable spleen cells from these pretreated BALB/c mice were transferred into naive syngeneic recipients which then were tested for DTH response and allograft survival to the relevant and irrelevant antigens. The radiosensitivity of this transferrable suppression was evaluated by exposing the adoptively transferred cell population to 3200 rads of C-irradiation prior to cell transfer. The phenotype of the cells transferring this suppressive response was performed by depleting specific populations of cells with monoclonal antibodies prior to cell transfer. In vivo the DTH response of the pretreated BALB/c mice was specifically suppressed to the relevant alloantigen, correlating with retention of CBA/j skin grafts for up to 42 days post engraftment without visual evidence of rejection, in comparison to control mice complete rejection of the skin graft in less than 8 days. In vitro, splenocytes from BALB/c recipients of pretreated syngeneic splenocytes containing large numbers of BALB/c anti-CBA/j T cells proliferated less in MLC and generated lower cytotoxic T cell responses to CBA/j alloantigens than did controls and suppressed the naive and sensitized BALB/c MLC and CTL responses to CBA/j alloantigen. This specific suppressive response to alloantigen was optimally transferred into syngeneic naive recipients when the adoptive transfer was performed on the sixth day after the last infusion received by the spleen cell donor mice. The adoptive transfer of this suppressive response was abrogated by the prior X-irradiation of the donor spleen cells and significantly abolished by the depletion of Thy-1+, Lyt-2+, L3T4- T lymphocytes.(ABSTRACT TRUNCATED AT 400 WORDS)

Quantitation of plasma levels of 8-methoxypsoralen by competitive enzyme-linked immunosorbent assay

An immunologic method for the quantitation of 8-methoxypsoralen (8-MOP) levels in human plasma has been developed. A monoclonal antibody recognizing 8-MOP was prepared by immunizing mice with an 8-MOP derivative conjugated to bovine serum albumin with 1-ethyl-3-(3-dimethylamino-propyl)-carbodiimide-HCl. The antibody was characterized by competitive enzyme-linked immunosorbent assay (ELISA) and recognizes 8-MOP (50% inhibition at 2 pmol) as well as structurally related psoralen derivatives including 4'-aminomethyl-4,5',8-trimethylpsoralen (50% inhibition at 50 pmol), 5-methoxypsoralen (50% inhibition at 150 pmole), and 6,4,4'-trimethylangelicin (50% inhibition at 360 pmol). The assay has a limit of sensitivity of 1 ng/ml plasma. For analysis of 8-MOP levels in plasma, samples were first extracted using SepPak C18 cartridges. The extracts were analyzed for 8-MOP levels both by ELISA and high-pressure liquid chromatography. There was a good correlation between the values determined by both methods (r = 0.92, p less than 0.0005). The development of immunologic methods should greatly facilitate the quantitation of 8-MOP levels in patient plasma.

Inhibition and induction of drug metabolism by psoralens: alterations in duration of sleep induced by hexobarbital and in clearance of caffeine and hexobarbital in mice

1. Hexobarbital (100 mg/kg i.p.) sleeping times in male CD-1 mice pretreated (-1 h) with a single i.p. injection of 150 mumol/kg of psoralen or coumarin analogues were increased, most markedly (6-fold) by linear, methoxy-substituted psoralens. 2. Hexobarbital sleeping times of mice which received three daily injections (231 mumol/kg; 50 mg/kg) of 8-methoxypsoralen (8-MOP) were 44% of controls (corn oil). 3. The whole-body half-life of caffeine (1 mg) in mice was 10.2, 1.2, and 0.37 h following 8-MOP (50 mg/kg per day) x 1, vehicle, and 8-MOP x 3 respectively. 4. The whole-body concentrations of hexobarbital (100 mg/kg dose) in mice 30 min after dosing were 14.3 +/- 0.9, 8.4 +/- 0.3, and 5.2 +/- 0.5 micrograms/ml (1 mouse = 150 ml) following 8-MOP (50 mg/kg per day) x 1, vehicle, and 8-MOP x 3 respectively. 5. It is concluded that, administered acutely, psoralen analogues inhibit hexobarbital metabolism in mice; and 8-MOP administered acutely inhibits the metabolism of caffeine and hexobarbital, but administered repeatedly increases their metabolism.

Extracorporeal photochemotherapy in the treatment of cutaneous T-cell lymphoma. Complexity of objective evaluation

The term cutaneous T-cell lymphoma (CTCL) encompasses the spectrum of diseases characterized by a monoclonal proliferation of malignant T lymphocytes predominantly of the mature T-helper cell type. These include mycosis fungoides, which is usually localized to the skin for many years, and the Sezary syndrome, the leukemic variant in which characteristic, bizarre lymphatic cells with deeply indented or cerebriform nuclei, the Sezary cells, infiltrate lymph glands and internal organs such as the spleen, liver, lungs, heart, and bone marrow. The condition is more common in men after their fourth decade. The treatment of CTCL varies depending on the stage of the disease. The skin of the patient is the primary index of effectiveness of therapy. Options range from topical steroids, topical nitrogen mustard, X-irradiation, electron beam irradiation, and 8-methoxypsoralen (8-MOP) combined with ultraviolet A photochemotherapy (PUVA), to leukapheresis and systemic chemotherapy. More recently, extracorporeal photochemotherapy (ECPC) has been introduced. The safety and efficacy of this modality is further investigated in six patients who fulfilled the criteria of diagnosis of CTCL. The problems encountered in objectively evaluating the clinical responses in the patients are outlined and improvements in the protocol to overcome these are suggested. The proposed mechanism of action is an immunostimulatory one and a procedure that is relatively free from side effects; it offers promise as a potential treatment for a difficult cancer.

PUVA-induced lymphomatoid papulosis in a patient with mycosis fungoides

The occurrence of lymphomatoid papulosis in patients with cutaneous lymphoma, particularly mycosis fungoides, has been described in medical literature. A 68-year-old woman affected by mycosis fungoides in the plaque stage noticed that multiple papulonodular lesions of lymphomatoid papulosis developed suddenly after a few sessions of PUVA therapy. The PUVA induction of lymphomatoid papulosis was confirmed by the appearance of new lesions after a second cycle of PUVA exposure on a limited area of the body. Complete regression of all PUVA-induced lymphomatoid papulosis lesions was achieved within a few weeks with oral prednisone and topical steroids. During the entire treatment the patches and plaques of mycosis fungoides persisted unchanged.

High-performance liquid chromotography analysis of 8-methoxypsoralen monoadducts and crosslinks in lymphocytes and keratinocytes

Human lymphocytes and murine keratinocytes were treated with clinically relevant doses of 8-methoxypsoralen and long-wavelength ultraviolet radiation. The extent of 8-MOP photoadduct formation was determined by liquid scintillation analysis. The distribution of photoadducts was determined by HPLC analysis of enzymatically hydrolyzed DNA from these cells. Analysis of photoadduct formation in lymphocytes and keratinocytes showed that 4',5'-monoadducts were the predominant photoadducts (42% and 41%, respectively). Monoadduct and crosslink yields were dependent on cell type as well as irradiating wavelength. The photochemical conversion of 400 nm-induced 4',5'-monoadducts to crosslinks, as well as 3,4-monoadducts in poly(dA-dT), was measured.

Treatment of rheumatoid arthritis by extracorporeal photochemotherapy. A pilot study

In a 6-month pilot study of 7 patients with rheumatoid arthritis, we tested a treatment involving the extracorporeal photoactivation of biologically inert methoxsalen (8-methoxypsoralen) by ultraviolet A energy to a form that covalently cross-links lymphocyte DNA; the injured cells are reinfused into the patient. Prior experimental studies had indicated that this regimen produces an immune reaction against antigens on treated T cells, and a clinical trial in patients with cutaneous T cell lymphoma had been successful. The current study patients were treated monthly, on 2 successive days (or biweekly, later on). Between 12 and 16 weeks of therapy, there appeared to be a breakpoint, after which the joint counts and joint scores of 4 of the patients began to improve. In 3 of the 4 patients, these measures eventually diminished by a mean of 71% and 80% of baseline values, respectively, and there was variable improvement in less direct indicators of clinical response. The joint counts and scores of the fourth patient improved modestly (by 33% and 59% of baselines, respectively) but he required alternative therapy, and those of the remaining 3 study patients did not improve. Mean slopes for the joint counts were significantly different from zero after the apparent breakpoint (but not before), whether one examined the 4 apparent responders (P = 0.01) or the entire group of 7 patients (P = 0.01). After completion of therapy, there was also a delay, of 2-3 months, in the clinical deterioration of those patients who had improved. There was only 1 mechanical adverse effect--a single episode of transient hypotension in 102 treatment sessions--and no toxic effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Formation and removal of 8-MOP-DNA photoadducts in keratinocytes: effects of calcium concentration and retinoids

8-methoxypsoralen (8-MOP)-DNA photoadducts were quantified in freshly isolated human and murine keratinocytes and cultured keratinocyte cell lines after in vitro treatment with 8-MOP (1-200 ng/ml) and ultraviolet A (UVA; 0.2-24.0 J/cm2). Greater doses of 8-MOP and UVA led to proportionately greater numbers of photoadducts, with a dose reciprocity relationship between the amounts of 8-MOP and UVA. No significant difference in photoadduct formation was observed between basal and differentiated cells. However, the transformed keratinocyte cell lines showed fewer photoadducts than did normal keratinocytes, which appeared to be correlated with the finding that the adduct formation was inhibited in normal keratinocytes cultured with phorbol 12-myristate 13-acetate, because this agent leads to epidermal hyperproliferation. In viable keratinocytes that were treated with a sublethal dose of 8-MOP and UVA (15 ng/ml and 1 J/cm2, respectively), 54% of photoadducts formed were removed over a 20-h period. Adduct removal depended on the calcium concentration in the media; cells cultured in standard high calcium levels showed a higher removal rate than those cultured in low-calcium media. The addition of retinoids (etretinate, acitretin, and 13-cis retinoic acid) to the culture induced 55 to 80% of suppression of the adduct removal. The calcium ionophore A23187 partially restored the suppression of photoadduct removal induced by retinoids. The present studies suggest that calcium performs an important role in the photoadduct removal and raise the possibility that the synergism of systemic retinoids and psoralen plus UVA photochemotherapy relates to the former's inhibition of repair of 8-MOP photoadducts in DNA.

Cytogenetic effects during extracorporeal photopheresis treatment of two patients with cutaneous T-cell lymphoma

The effect of extracorporeal photopheresis (EP) on various cytogenetic parameters has been investigated. During EP the photoactivatable agent 8-methoxypsoralen (8-MOP) was administered orally. After 2 h a leukocyte-enriched blood fraction was collected by haemocentrifugation, irradiated with UVA extracorporeally, and reinfused to the patient. Two patients suffering from cutaneous T-cell lymphoma showed a marked clinical improvement in response to therapy. In order to investigate the cytogenetic effects and mutagenic risk of EP, the mitotic index (MI), the type and number of chromosomal aberrations and the rate of sister chromatid exchanges (SCE) were studied. Following EP treatment the patients' lymphocytes were cultured and stimulated with phytohaemagglutinin (PHA) for 48 or 72 h. The cultured lymphocytes showed a decreased MI after 48 h as an indicator of cytotoxic effects, but not after 72 h. In lymphocyte cultures not stimulated with PHA, the MI was decreased even after 72 h. The number of chromosomal aberrations and SCE were increased upon treatment, but only transiently, returning to basal levels between consecutive treatments. Our data provides no evidence for increased mutagenic risk as a consequence of effective EP treatment.

Photoinactivation of T-cell function with psoralen and UVA radiation suppresses the induction of experimental murine graft-versus-host disease across major histocompatibility barriers

Bone marrow transplantation is employed in the treatment of a number of hematologic and malignant diseases. A major complication is the induction of graft-versus-host disease. Whereas removal of T lymphocytes from the donor marrow effectively reduces the incidence of graft-versus-host disease, the incidence of graft failure often increases when T cells are depleted from the transplanted marrow. In the current study, photoinactivation of the donor cells with 8-methoxypsoralen coupled with exposure to long-wavelength ultraviolet radiation (PUVA therapy) was used to inactivate the response of the donor T cells against the host. PUVA therapy suppressed the ability of spleen cells to respond to alloantigen in the in vitro mixed lymphocyte reaction. The induction of acute graft-versus-host disease across complete major histocompatibility barriers in lethally X-irradiated mice was significantly suppressed after bone marrow transplantation with photoinactivated bone marrow cells. Long-term survivors demonstrated allogeneic reconstitution and partial restoration of T-cell function. Because PUVA therapy had no inhibitory effect on hematopoiesis, these data suggest that using phototherapy to inactivate the alloreactivity of T cells may provide an alternative to purging T cells from the donor marrow, thus suppressing both the incidence of graft-versus-host disease and the incidence of graft failure.

Treatment of cutaneous T cell lymphoma with a combination of low-dose interferon alfa-2b and retinoids

In a pilot study the therapeutic effect and side effect profile of low-dose interferon alfa-2b in combination with a retinoid for the treatment of cutaneous T cell lymphoma were evaluated. Seven patients (four women, three men) with histologically confirmed cutaneous T cell lymphoma were included. Four patients had received therapy previously. The treatment schedule consisted of 2 million U of interferon alfa-2b administered subcutaneously three times per week and oral 13-cis-retinoic acid, 1 mg/kg/day, with subsequent dose reduction in case of response. The combination therapy produced two complete and two partial remissions. Responses were maintained by continuous therapy for up to 15 months even after dose reduction of both agents by 50%. Side effects were negligible and did not result in discontinuation of treatment in any patient.

Prevention of cyclophosphamide-induced and spontaneous diabetes in NOD mice by syngeneic splenocytes treated with cytotoxic drugs

Infusions of syngeneic T-cells, lethally damaged with ultraviolet A light (UVA) and 8-methoxypsoralen (8-MOP), have been reported to prevent or ameliorate a number of autoimmune diseases in humans and in animal models of autoimmune disease. We previously demonstrated that the combination of UVA/8-MOP, or deoxycoformycin and deoxyadenosine (dCF/dAdo), damaged human lymphoid cells by inducing DNA strand breakage and stimulating poly (ADP-ribosyl)ation. These cells subsequently underwent programmed cell death ("apoptosis"). These findings suggested a common mechanism of lymphocyte damage, and that in vitro treatment of T-cells with cCF/dAdo might substitute for UVA/8-MOP. This hypothesis was tested in a model of autoimmune diabetes in the NOD mouse. Young adult female NOD/Wehi mice were given 350 mg/kg cyclophosphamide (CP) on day 1 to induce rapid-onset diabetes and divided into five treatment groups. Four groups received approximately 50 x 10(6) syngeneic mouse splenocytes that had been treated with various cytotoxic agents. 27/40 (68%) of the CP-only control group and 14/30 (48%) of the group given untreated splenocytes developed diabetes. By contrast, only 2/20 (10%) mice of UVA/8-MOP and 3/23 (14%) of dCF/dAdo-treated splenocyte groups developed diabetes (P < 0.01). Diabetes in high spontaneous-diabetes incidence NOD/Lt female mice was also greatly reduced (4/8 untreated vs 1/7 treated; (< 0.05). We postulate that cytotoxic damage to activated splenic T-cells allows their recognition by host T-cells and results in a protective response against autoreactive cells as a form of T-cell vaccination.(ABSTRACT TRUNCATED AT 250 WORDS)

Production of hydrogen peroxide by cutaneous T-cell lymphoma following photopheresis with psoralens and ultraviolet light

Treatment of peripheral blood mononuclear cells with 8-methoxypsoralen (8-MOP) and ultraviolet light, a procedure known as PUVA, has been found to be useful in the management of systemically disseminated cutaneous T-cell lymphoma (CTCL). In the present study we used a highly sensitive flow cytometric assay in conjunction with the hydroperoxide-sensitive dye 2',7'-dichlorofluorescein diacetate to measure intracellular hydrogen peroxide in normal lymphocytes and CTCL following PUVA treatment. Based on their laser light-scattering properties, lymphocytes were separated into three major subpopulations. We found that ultraviolet light alone caused an increase in the hydrogen peroxide content of each of the subpopulations, a response that was augmented when the cells were pretreated with 8-MOP (50 ng/ml). Cells from CTCL patients were more sensitive to the effects of 8-MOP than were normal lymphocytes. In both cell types, the production of hydrogen peroxide was found to be inhibitable by catalase. We noted an increase in hydrogen peroxide production following photopheresis; however, this was observed only 24 h after treatment. In addition, a further increase in hydrogen peroxide production was observed in lymphocytes isolated from peripheral blood that had been obtained from patients at 15 min after a second photopheresis treatment. Hydrogen peroxide is known to modulate the action of cytokines as well as the immunological responses of leukocytes. Our data suggest that the production of hydrogen peroxide by lymphocytes may be important in the action of PUVA in CTCL.

Therapeutic potential of plant photosensitizers

Many bioactive phytochemicals have been shown in recent years to be photosensitizers, i.e. their toxic activities against viruses, micro-organisms, insects or cells are dependent on or are augmented by light of certain wavelengths. These activities are often selective, and this has led to the concept of therapeutic prospects in the control of infectious diseases, pests and cancer. Reaction mechanisms commonly involve singlet oxygen and radicals, which are thought to cause photodamage to membranes or macromolecules. The main classes of plant photosensitizers reviewed here are polyyines (acetylenes, thiophenes and related compounds); furanyl compounds; beta-carbolines and other alkaloids; and complex quinones. We propose that within each group of phytochemicals there are several representatives that merit further study for therapeutic abilities in appropriate animal models.

Mechanisms of lymphocytotoxicity induced by extracorporeal photochemotherapy for cutaneous T cell lymphoma

Extracorporeal photochemotherapy is an effective treatment for cutaneous T cell lymphoma but its mode of action is uncertain. The reduction in viability of patients' photoirradiated buffy coat lymphocytes was correlated with a 35% increase in DNA single-strand breaks and marked decreases in cellular ATP and NAD levels (to 58 and 34% of control, respectively) immediately after photoirradiation. Complementary in vitro studies were conducted with normal human peripheral blood lymphocytes using a Therakos ultraviolet A (UVA) light box. UVA light was cytotoxic on its own but was potentiated by 8-methoxysporalen. 3-aminobenzamide, a poly (ADP-ribose) synthetase inhibitor, mitigated the cytotoxic effect of ultraviolet A light in the presence of 8-methoxypsoralen in lymphocytes and reduced the amount of nucleotide depletion they caused. 10 J/cm2 of UVA light in the presence of 300 ng/ml 8-methoxypsoralen increased the poly (ADP-ribose) synthetase activity of peripheral blood lymphocytes. Exposing lymphocytes to deoxycoformycin and deoxyadenosine was found to induce biochemical and physical effects similar to those of photochemotherapy. In summary, we have shown that the lymphocytotoxic effect of extracorporeal photochemotherapy for cutaneous T cell lymphoma is apparently mediated by DNA damage, subsequent poly (ADP-ribosyl)ation and adenine nucleotide depletion. It is not known how the DNA damage and resultant biochemical effects relate to the possible immunological mechanism of extracorporeal photochemotherapy; however, it is possible that its effects can be mimicked by other DNA-damaging agents.

Treatment of cutaneous T-cell lymphomas (CTCL) with extracorporeal photochemotherapy--preliminary report

Since August of 1988, we have treated seven CTCL patients with extracorporeal photochemotherapy, including two with tumor-stage mycosis fungoides (MF) showing mucinous degeneration, two with plaque-stage MF, and two with erythrodermatous MF. One was withdrawn just after the first trial. For each patient, the phenotypes of peripheral blood lymphocytes were analyzed by flow cytometry in terms of the percentages of OKT11, OKT3, OKT4, Leu9, OKT8, B1, Tac, OKT9, OKIa1, Leu7, Leu3a/4B4, and Leu3a/2H4 cells. These parameters were compared with the clinical responses according to skin score. The two patients with tumors died, but the five patients without tumors did not. Three of the 6 patients responded to the treatment. Side effects that are often associated with standard chemotherapy, such as bone marrow suppression, gastrointestinal symptoms and hair loss, were not observed. One cardiovascular event (1 patient) occurred. No significant changes in T-cell subsets were seen during the course of therapy. These preliminary data suggest that extracorporeal photochemotherapy may be effective for CTCL other than tumor-stage MF.

Photopheresis for the treatment of cutaneous T cell lymphoma

We investigated the use of extracorporeal chemotherapy (photopheresis) in eight patients with cutaneous T cell lymphoma. Initially described by Edelson et al. for the treatment of erythrodermic cutaneous T cell lymphoma, we have expanded the treatment to include patients with extensive patch/plaque disease as well as tumor-stage disease. Four of five patients with erythrodermic stage disease had either a complete or a partial clinical remission with photopheresis alone. One patient with extensive patch/plaque disease continued to have a partial clinical remission of 7 months' duration with photopheresis alone. Of the two patients with tumor-stage disease, one remained without evidence of clinical disease at 10 months with photopheresis alone, whereas the second patient had a partial clinical remission of 5 months with a combination of local radiation therapy followed by monthly photopheresis. The skin biopsy specimen obtained from the patient with tumor-stage disease in complete clinical remission did not show cutaneous T cell lymphoma. We conclude that photopheresis is an effective modality alone or in combination with adjunctive therapy for erythroderma, extensive patch/plaque disease, and some tumor-stage disease.

Mycosis fungoides and the Sézary syndrome: pathology, staging, and treatment

Mycosis fungoides and the Sézary syndrome are forms of cutaneous T-cell lymphoma. Mycosis fungoides is an uncommon disease: only about 500 new cases are diagnosed in the United States annually. The median age of onset is 55 years and there is a 2:1 male predominance. The etiology of mycosis fungoides is unknown. Although occupational exposures have been implicated, case control studies fail to support this hypothesis. Mycosis fungoides is typified by cutaneous plaques which may evolve into tumors over the course of time. It is often preceded by a lengthy pre-mycotic phase prior to the time of definitive diagnosis. In its earliest diagnostic phase, there may only be slightly scaling patches with a limited distribution. Indurated lesions evolve into plaques, which may become more generalized in their distribution. As the severity of skin involvement increases, there is an increasing likelihood of spread to extracutaneous sites. The pathology of this disease is marked by involvement of the epidermis (Pautrier microabscesses). Immunologic studies characterize these cells as belonging to the helper T-cell subset. Genotypic analysis demonstrates monoclonal rearrangements of the T-cell receptors of the infiltrating cells. The staging system for mycosis fungoides considers the extent of skin involvement, presence of lymph node or visceral disease, and detection of abnormal cells in the peripheral blood. Patients with disease limited to the skin (90% of newly diagnosed cases) are treated best with topical or cutaneous therapies. Common modalities include psoralen photochemotherapy (PUVA), topical chemotherapy (nitrogen mustard) and total skin electron beam therapy. Both topical nitrogen mustard and electron beam therapy have good initial response rates (73% and 100%) and may achieve long-term disease-free survival, especially in patients with initially limited disease. Even if the response is incomplete or relapse occurs, substantial and very important palliation is generally achieved with topical therapy. Recurrent or resistant cutaneous disease will require the use of sequential topical treatment. The median survival time of patients who present with disease limited to the skin is greater than 10 years, and many deaths in this group are from intercurrent causes, especially in patients with limited or generalized plaque disease. If cutaneous tumors are present, the majority of these patients will eventually die from disease-related causes. The prognosis of patients who develop extracutaneous disease is exceedingly poor (median survival time, approximately 1 year).(ABSTRACT TRUNCATED AT 400 WORDS)

Extracorporeal photopheresis in psoriasis vulgaris: clinical and immunologic observations

Four patients with chronic refractory plaque-type psoriasis without arthropathy were treated with extracorporeal photopheresis every other week for 6 to 13 months. In patients 1 and 2, methotrexate was administered concomitantly during the initial part of the trial; the dose was gradually tapered and the drug was discontinued by 6 months. Both patients improved to 23% and 62% of baseline values for percentage of body surface involvement, but their disease then flared when maintenance extracorporeal photopheresis was used alone. Substantial improvement again occurred when lower doses of methotrexate were administered with extracorporeal photopheresis. Patients 3 and 4 were treated initially with extracorporeal photopheresis alone and both improved to 50% and 52% of baseline body surface involvement, respectively, after 4 months of treatment. However, their disease flared because of factors unrelated to treatment. Extracorporeal photopheresis was well tolerated by all patients without evidence of overt toxicity. However, prolonged treatment with extracorporeal photopheresis/methotrexate was accompanied by a decrease in skin reactivity to recall antigens and by decreased capacity of lymphocytes to produce interleukin 2 in response to polyclonal stimuli in vitro. These findings indicate that alternate-week extracorporeal photopheresis has a definite but incomplete suppressive effect on psoriasis vulgaris that may be mediated through an effect on lymphokine production by photomodified cells and that the therapeutic effect of extracorporeal photopheresis may be enhanced by concomitant administration of low doses of methotrexate.

Treatment of a case of mycosis fungoides and one of parapsoriasis en plaque with topical PUVA using a monofunctional furocoumarin derivative, 4,6,4'-trimethylangelicin

A case of plaque stage mycosis fungoides and one of parapsoriasis en plaque were treated with topical PUVA therapy using a monofunctional furocoumarin derivative, 4,6,4'-trimethylangelicin (TMA). Both patients showed complete clearance of eruptions within 16 treatments. The therapeutic effectiveness of TMA was confirmed by the fact that those eruptions exposed to UVA alone, without TMA application, showed slower and less significant improvement. Histologically, dermal infiltrates of mycosis cells and associated epidermotrophism disappeared almost completely in response to TMA PUVA. No side effects or changes in values in laboratory examinations were observed during treatment.

Cell membrane DNA: a new target for psoralen photoadduct formation

The effects of 8-methoxypsoralen plus long wavelength ultraviolet radiation on cell membrane DNA were examined. Treatment of human lymphocytes with 100 ng/ml 8-methoxypsoralen and 5 J/cm2 UVA led to the formation of 7.1 +/- 3.8 photoadducts per million bases. A monoclonal antibody, specific for 8-methoxypsoralen 4',5'-monoadducts, was used to detect photoadducts in the cell membrane DNA of human lymphocytes and three lymphoblastoid cell lines. Treatment of lymphocytes with 8-MOP and UVA reduced the lymphocyte DNA binding capacity by 56%. Cell membranes of normal lymphocytes were shown to contain three high affinity DNA binding proteins of 28, 59, and 79 kDa, respectively.

Clinical features associated with transformation of cerebriform T-cell lymphoma to a large cell process

Some patients with cerebriform T-cell lymphoma (CTCL) undergo morphologic transformation to a large cell lymphoma. From a series of 113 patients with CTCL, 22 patients were identified with transformed CTCL. Stages of involvement at diagnosis were: I (seven), II (four), III (four), IV (seven). Nine patients had transformation at the initial diagnosis while the median time from diagnosis to transformation in the other 13 patients was 16 months (range: 3 months-6 years). Thirteen had transformation extracutaneously: lymph nodes (eight), central nervous system (two), and other extranodal sites (three). T cell markers were identified in all cases; of 15 cases with complete phenotypes, there were eight T-helper, three T-suppressor, and four aberrant T phenotypes. Serology for human T-leukemia virus-I (HTLV-I) was negative in eight patients tested. Median survival from diagnosis was 27 months compared to 53 months in 53 patients without transformation (p = 0.003). Despite combination chemotherapy in 12 patients following transformation, median survival after transformation was 12 months and only 7 months with extracutaneous disease. The likelihood of transformation could not be predicted by the initial histology, immunophenotype, or stage of disease.

Photocarcinogenicity of psoralens used in PUVA treatment: present status in mouse and man

There is good evidence that 8-methoxypsoralen is photocarcinogenic in psoriatic patients undergoing long-term photochemotherapy (PUVA) in the U.S.A. However, this conclusion has not been supported by two major European studies which have indicated that PUVA is a tumour promoter of damage initiated by other agents. Variation in PUVA treatment protocols in the U.S.A. and Europe may partly account for the different conclusions. There is much interest in the therapeutic potential of monofunctional psoralens. It is hoped that these may reduce long-term risk. Monofunctional and cross-linking psoralens have been shown to be photocarcinogenic in mouse skin. The relative risk of different compounds may be assessed in the mouse, but it is important to base comparisons on dose protocols that have been shown to be therapeutically effective.

Photosensitization by selected anticancer agents

Novel anticancer anthrapyrazoles and anthracenediones are available as alternatives to the cardiotoxic clinical agents, doxorubicin and daunorubicin. Certain representatives of these new classes of compounds possess photosensitizing properties. The structural features influencing the photophysical parameters of these agents are discussed. Photosensitizing reactions involving singlet oxygen production, free radical formation, decomposition of hydrogen peroxide and organic hydroperoxides, oxidation of certain biochemical electron donors, DNA damage and killing of human leukemic cells in vitro in the presence of photoactive anthrapyrazoles, anthracenediones and anthracyclines are described.

BE-2 antigen: appearance in activation and long-term growth of T cells

The BE-2 lymphocyte surface protein is frequently expressed by the malignant cells of cutaneous T-cell lymphoma (CTCL) but is not detectable on the surface of normal resting peripheral blood lymphocytes. The expression of BE-2 by normal T cells can be induced by lectin stimulation. Membrane expression of BE-2 surpasses that of the membrane receptor for IL-2, another T-cell activation marker, at day 5. The peak expression of BE-2 appears at day 6-8. The appearance of BE-2 could also be demonstrated after anti-CD3 and allogeneic stimulation. Long-term T-cell clones derived from normal donors and maintained in culture with periodic stimulation were also found to express BE-2 continuously. Thus, BE-2 is a late activation marker not expressed on normal peripheral blood lymphocytes and pathologically expressed on circulating malignant cells in the disease CTCL.

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.