Retinoids synergize with interleukin-2 to augment IFN-gamma and interleukin-12 production by human peripheral blood mononuclear cells

Harnessing the immune system in the treatment of cutaneous T cell lymphomas

Cutaneous T cell lymphomas are a rare subset of non-Hodgkin's lymphomas with predilection for the skin with immunosuppressive effects that drive morbidity and mortality. We are now appreciating that suppression of the immune system is an important step in the progression of disease. It should come as no surprise that therapies historically and currently being used to treat these cancers have immune modulating functions that impact disease outcomes. By understanding the immune effects of our therapies, we may better develop new agents that target the immune system and improve combinatorial treatment strategies to limit morbidity and mortality of these cancers. The immune modulating effect of therapeutic drugs in use and under development for cutaneous T cell lymphomas will be reviewed.

Tazarotene 0.1% Cream as Monotherapy for Early-Stage Cutaneous T-Cell Lymphoma

BACKGROUND

Numerous treatments are available for cutaneous T-cell lymphoma (CTCL), including systemic retinoids. Very few data are available on topical retinoids.

OBJECTIVES

The aim of this study was to evaluate the safety and efficiency of tazarotene as monotherapy for early-stage CTCL.

METHODS

An open-label, prospective study of tazarotene as monotherapy for stages IA to IIA CTCL was conducted. Index lesions on 10 patients were followed for 6 months on treatment, plus at least 6 months off treatment.

RESULTS

Six patients (60%) showed complete response (CR). Erythema, scaling, thickness, and lesion area decreased progressively throughout treatment. The mean time to CR was 3.8 months; CR was durable for at least 6 months in 83%. Of the 4 patients (40%) without CR, 2 (20%) had stable disease and 2 (20%) stopped the medication because of local side effects; none showed progression.

CONCLUSIONS

This is the first Canadian trial providing evidence that topical tazarotene has excellent potential as a monotherapy agent for stages I to IIA CTCL.

The Role of Systemic Retinoids in the Treatment of Cutaneous T-Cell Lymphoma

Retinoids are natural and synthetic vitamin A analogs with effects on cell proliferation, differentiation, and apoptosis. They have significant activity in hematologic malignancies and have been studied extensively in cutaneous T-cell lymphoma. Retinoids bind to nuclear receptors and exert their effects through moderation of gene expression. Retinoic acid receptor and retinoic X receptor exert regulatory activity in vivo, binding to distinct ligands. Studies investigating systemic retinoids as monotherapy and in combination with other agents active against cutaneous lymphoma are reviewed. Side effects associated with retinoids include teratogenicity, dyslipidemias, and hypothyroidism, which should be carefully monitored in patients receiving treatment.

Gingyo-san enhances immunity and potentiates infectious bursal disease vaccination

The purpose of the present study was to investigate the effects of Gingyo-san (GGS), a traditional Chinese medical formula, on peripheral lymphocyte proliferation and serum antibody titers in chickens vaccinated against the infectious bursal disease (IBD) virus. Treatment groups were fed one of three doses of GGS in their diet (0.5%, 1.0% and 2.0%, w/w), and the IBD vaccine was administered at 1 and 3 weeks of age. At Weeks 8, 12 and 16, changes in serum IBD antibody titers were measured via the micro-method and T cell proliferation. In gene expression experiments, GGS-treated peripheral T lymphocytes were stimulated with concanavalin A (ConA) for 24 h. The mRNA expression of interleukin-2 (IL-2), interferon-γ (IFN-γ), interleukin-4 (IL-4) and interleukin-12 (IL-12) was determined using a semi-quantitative RT-PCR assay. The results showed that a low dose of GGS could significantly raise the antibody titers. Medium and high doses of GGS enhanced IL-2 and IFN-γ production. GGS altered the expression of IL-4 and IL-12 in T lymphocytes. CD4⁺ T lymphocyte development was also skewed towards the Th1 phenotype. GGS enhanced cell-mediated immunity and augmented the effects of IBD vaccination in strengthening subsequent anti-viral responses.

Systemic cancer therapy: evolution over the last 60 years

The 1940s marked the beginning of an era of important discoveries that contributed to modern concepts underlying the current practice of cancer chemotherapy, such as the log kill hypothesis reported by Skipper, the Norton-Simon hypothesis, and the Goldie-Coldman hypothesis. The early success of nitrogen mustards and antifolates in the treatment of hematologic malignancies paved the way for drug discovery platforms, which resulted in the generation of more drugs that nonetheless predominantly are genotoxic. The turn of the new millennium marked a new phase in the evolution of cancer chemotherapy. Scientific progress in the preceding 60 years elucidated the important ideas behind tumor microenvironment and 'targeted' therapy that had their inception in the late 19th century. Breakthroughs in molecular biology have paved the way for the development of novel agents that modulate the dysregulated molecular pathways implicated in carcinogenesis. The key approaches and evidence pertinent to the clinical development of these novel agents are presented in this review.

Chemoimmunotherapy in the treatment of metastatic gastric cancer

Docetaxel, capecitabine and 5-fluorouracil have been shown to be active in the treatment of metastatic gastric adenocarcinoma. Consistent with this finding, the aim of this study was to test this combination in a clinical trial. Forty-one patients with metastatic gastric adenocarcinoma and a median age of 64 years were recruited for the study. The treatment was based on the administration of docetaxel 60 mg/m2 every 4 weeks, leucovorin 200 mg/m2, 5-fluorouracil 400 mg/m2 bolus, and capecitabine 1000 mg/m2 twice daily on days 1 and 2 every 2 weeks. Patients achieving a clinical benefit were treated, as maintenance immunotherapy, with low-dose interleukin-2 and 13-cis-retinoic acid. The primary end point of this phase II study was the response rate. The secondary end points relied on the evaluation of the immunological parameters, toxicity, and progression-free survival and overall survival. The overall response rate in the 41 evaluable patients was estimated to be 49%. Median progression-free and overall survival was 9.5 and 21.1 months, respectively. Grade 3 and 4 hematological toxicities were neutropenia and thrombocytopenia in 44 and 5% of patients, respectively. A sustained improvement of evaluated immunological parameters with a negligible toxicity profile was observed in the 27 patients treated with interleukin 1-2/13-cis-retinoic acid. Docetaxel in combination with leucovorin, 5-fluorouracil and capecitabine followed by low-dose interleukin 1-2 and 13-cis-retinoic acid is well tolerated, and shows a significant activity in patients with metastatic gastric adenocarcinoma.

Phase II study of interleukin-2 and 13-cis-retinoic acid as maintenance therapy in metastatic colorectal cancer

PURPOSE

We have previously shown that low-dose interleukin-2 (IL-2) and 13-cis-retinoic acid (13-cis-RA) improved lymphocyte and natural killer (NK) cell count of patients with advanced tumors showing a clinical benefit from chemotherapy. The primary endpoint of this study was to ask whether IL-2 and 13-cis-RA improved (> or =30%) lymphocyte and NK cell count in patients with metastatic colorectal cancer (MCRC) that had a clinical benefit from induction chemotherapy. Secondary endpoint was the evaluation of toxicity, progression-free survival (PFS), and overall survival (OS).

PATIENTS AND METHODS

Forty patients with MCRC, showing a clinical benefit from chemotherapy, were treated with subcutaneous low-dose IL-2 (1.8 x 10(6) IU) and oral 13-cis-RA (0.5 mg/kg) in order to maintain responses and improve survival through the increase of lymphocyte and NK cells. The biological parameters and the clinical outcome of these patients were compared with those of a control group of patients (80) with a similar disease status, including clinical benefit from chemotherapy.

RESULTS

The most common adverse events were mild cutaneous skin rash and fever. After 4 months and 2 years of biotherapy, a statistically significant improvement was observed in lymphocyte and number of NK cells with respect to baseline values and to controls. After a median follow-up of 36 months, median PFS was 27.8 months, while median OS was 52.9 months.

CONCLUSION

These data show that maintenance immunotherapy with low-dose IL-2 and oral 13-cis-RA in patients with MCRC showing a clinical benefit from chemotherapy is feasible, has a low toxicity profile, improves lymphocyte and NK cell count. An improvement in the expected PFS and OS was also observed. A randomized trial is warranted.

Direct and indirect effects of retinoic acid on human Th2 cytokine and chemokine expression by human T lymphocytes. BMC Immunol. 2006;7:27. [PMID: 17118196 PMCID: PMC1665462 DOI: 10.1186/1471-2172-7-27]

BACKGROUND

Vitamin A (VA) deficiency induces a type 1 cytokine response and exogenously provided retinoids can induce a type 2 cytokine response both in vitro and in vivo. The precise mechanism(s) involved in this phenotypic switch are inconsistent and have been poorly characterized in humans. In an effort to determine if retinoids are capable of inducing Th2 cytokine responses in human T cell cultures, we stimulated human PBMCs with immobilized anti-CD3 mAb in the presence or absence of all-trans retinoic acid (ATRA) or 9-cis-RA.

RESULTS

Stimulation of human PBMCs and purified T cells with ATRA and 9-cis-RA increased mRNA and protein levels of IL-4, IL-5, and IL-13 and decreased levels of IFN-gamma, IL-2, IL-12p70 and TNF-alpha upon activation with anti-CD3 and/or anti-CD28 mAbs. These effects were dose-dependent and evident as early as 12 hr post stimulation. Real time RT-PCR analysis revealed a dampened expression of the Th1-associated gene, T-bet, and a time-dependent increase in the mRNA for the Th2-associated genes, GATA-3, c-MAF and STAT6, upon treatment with ATRA. Besides Th1 and Th2 cytokines, a number of additional proinflammatory and regulatory cytokines including several chemokines were also differentially regulated by ATRA treatment.

CONCLUSION

These data provide strong evidence for multiple inductive roles for retinoids in the development of human type-2 cytokine responses.

High Clinical Response Rate with Multimodality Immunomodulatory Therapy for Sézary Syndrome

PURPOSE

The goal of this study was to evaluate the clinical response rate of patients with Sézary syndrome (SS) to multimodality immunomodulatory therapy consisting of extracorporeal photopheresis in combination with >/= 2 systemic biologic response modifiers (interferon-, interferon-, retinoids, and/or sargramostim) and psoralen plus UV-A.

PATIENTS AND METHODS

Twenty-eight patients who met established criteria for SS were treated with multimodality immunomodulatory therapy at the Hospital of the University of Pennsylvania between January 2000 and December 2002. All patients received > 6 cycles of extracorporeal photopheresis. Patients were categorized into groups based on their response to therapy.

RESULTS

An overall clinical response of 89% was achieved with multimodality immunomodulatory therapy. Twenty-nine percent of patients exhibited a complete response, characterized by no evidence of cutaneous disease and a Sézary count 5%. Sixty-one percent exhibited a partial response. Eleven percent were nonresponders.

CONCLUSION

Based on our experience, multimodality immunomodulatory therapy is an exceptionally effective treatment for SS. The durability of response and impact on overall survival remains to be determined; however, this approach offers an appealing alternative to treatments associated with higher morbidity rates.

Current approaches to advanced-stage non-small-cell lung cancer: first-line therapy in patients with a good functional status

Lung cancer is the leading cause of cancer-related death among men and women in the United States. Approximately 80-85% of lung cancer cases are non-small-cell lung cancer (NSCLC), and approximately 65% of these patients have advanced-stage (IIIB/IV) disease at diagnosis. The median survival for patients with advanced-stage NSCLC treated with platinum-based chemotherapy is a disappointing 8-10 months. This article reviews the current status of chemotherapy in patients with a good functional status and evaluates the treatments in terms of efficacy, toxicity, survival, and impact on quality of life in the first-line treatment. Biologic agents such as bevacizumab and erlotinib have been investigated in phase III trials in the first- and second-line setting. These agents could play a role in select patient populations. This article also highlights some of the more promising new strategies, such as advances in pharmacogenomics and immune-based therapy. There is a clear need for improvement in the current standard of care. Well-designed clinical trials with appropriate patient selection, as well as continued efforts in translational research and pharmacogenomics, are crucial for progress in this disease.

New insights into the molecular biology and targeted therapy of cutaneous T-cell lymphomas

Cutaneous T-cell lymphoma is an extra-nodal non-Hodgkin lymphoma of mature T cells. These tumor cells home to and persist in the skin,producing a broad spectrum of clinical entities. Recent results of basic research on tumor biology and tumor immunology as well as molecular genetics of cutaneous T-cell lymphoma have fostered the development of new therapeutic approaches. Several clinical trials testing these targeted therapies have shown encouraging results. This article provides an overview of recent research developments and therapeutic strategies for cutaneous T-cell lymphoma.

Multicenter Phase 2 Study of Interleukin-2 and 13-Cis Retinoic Acid as Maintenance Therapy in Advanced Non-Small-Cell Lung Cancer

High serum levels of vascular endothelial growth factor (VEGF) are a poor prognostic factor for patients with advanced non-small-cell lung cancer (NSCLC). We have previously shown that low-dose interleukin (IL)-2 and 13-cis retinoic acid (RA) decreased VEGF and improved the immune function of patients with advanced tumors treated with chemotherapy. The primary end point of this study was to verify whether IL-2 and RA decreased serum VEGF in NSCLC patients showing a clinical benefit from chemotherapy. The secondary end point was the evaluation of clinical outcome. We treated 38 patients with advanced NSCLC who had a complete or partial response or disease stability to chemotherapy and had a median serum VEGF level of 508 ng/mL; as maintenance therapy, they received subcutaneous IL-2 (1.8 x 10(6) IU) and oral RA. Matched controls (n = 87) were selected from a large cohort of patients with a similar disease status, including clinical benefit from chemotherapy. The most common adverse events were mild cutaneous skin rash and fever. Serum VEGF decreased to a mean level of 152 ng/mL (P = 0.0002). A statistically significant improvement in immune function was observed (lymphocyte and natural killer cell numbers and CD4+/CD8+ ratio) with respect to baseline values and controls. An improvement in the clinical outcome was also observed compared with controls. These data show that the administration of low-dose subcutaneous IL-2 and oral RA to patients with advanced NSCLC showing a clinical benefit from chemotherapy is feasible with a low-toxicity profile, decreases VEGF, and seems to improve progression-free and overall survival.

Immunopathogenesis and therapy of cutaneous T cell lymphoma

Cutaneous T cell lymphomas (CTCLs) are a heterogenous group of lymphoproliferative disorders caused by clonally derived, skin-invasive T cells. Mycosis fungoides (MF) and Sezary syndrome (SS) are the most common types of CTCLs and are characterized by malignant CD4(+)/CLA(+)/CCR4(+) T cells that also lack the usual T cell surface markers CD7 and/or CD26. As MF/SS advances, the clonal dominance of the malignant cells results in the expression of predominantly Th2 cytokines, progressive immune dysregulation in patients, and further tumor cell growth. This review summarizes recent insights into the pathogenesis and immunobiology of MF/SS and how these have shaped current therapeutic approaches, in particular the growing emphasis on enhancement of host antitumor immune responses as the key to successful therapy.

Comparison of selective retinoic acid receptor– and retinoic X receptor–mediated efficacy, tolerance, and survival in cutaneous t-cell lymphoma

Primary cutaneous T-cell lymphomas are non-Hodgkin's lymphomas with varied clinical presentation and prognosis. The most common subtypes of cutaneous T-cell lymphomas are the epidermotropic variants mycosis fungoides and Sézary syndrome. Treatment of mycosis fungoides has encompassed a variety of modalities including the use of retinoids with several studies evaluating their efficacy. The reported benefits and duration of response have varied in published data. The biological effect of retinoids is mediated by specific receptor families, retinoic acid receptor (RAR) and retinoic X receptor (RXR), with subsequently altered gene expression. There are no data available on cutaneous T-cell lymphomas that compare RAR and RXR retinoids. The objective of our retrospective, nonrandomized, single-center study was to compare the response, survival outcomes, and toxic effects in our phase II trial of the RAR-specific retinoid, all-trans retinoic acid, with clinical use of the RXR-specific retinoid, bexarotene, in patients with mycosis fungoides/Sézary syndrome who have relapsed. There was no statistical difference in response rates (12% vs 21%), response duration (20.5 vs 7.3 months), event-free survival time (4 vs 5 months), or median survival when corrected for length of follow-up. Both have favorable toxicity profiles that can be managed with medications. The toxicity profile caused by bexarotene seems to be more limited to laboratory values and better tolerated, although generally associated with more severe grades of toxicity. In conclusion, both retinoids have modest objective response rates and, therefore, most likely will have limited impact as monotherapeutic agents. However, the immunomodulatory effects of RAR and RXR retinoids provide a rational basis for using retinoids in combination with other biologic immune response modifiers, phototherapy, or cytotoxic chemotherapy.

CCR4 Expression by Atypical T Cells in Systemic Pilotropic Lymphoma: Its Behavior under Treatment with Interferon Gamma, Topical PUVA and Systemic Retinoid

We describe an 88-year-old Japanese patient with pilotropic T cell lymphoma involving the peripheral blood as well as lymph nodes. This patient presented with multiple red follicular papules, confluent, infiltrated erythematous plaques and nodules. Moreover, he was conspicuous for the presence of total alopecia of the scalp and eyebrows. Histopathologically, the lesional skin showed dense follicular and perifollicular infiltrates of atypical lymphocytes. The flow cytometry disclosed the presence of weakly CD4+ CCR4+ cell populations that would not be detected in the peripheral blood from healthy controls. The patient responded well to topical PUVA and systemic etretinate (retinoid-PUVA) and intravenous IFN-gamma. Parallel with the decrease in atypical cells in the peripheral blood, the percentage of weakly CD4+ CCR4+ T cells declined. However, about 1 week after we discontinued this treatment because of the side effects, the lymph node swelling became prominent, and, 4 weeks later, the patient died before restarting any specific chemotherapy.

Low-dose oral bexarotene in combination with low-dose interferon alfa in the treatment of cutaneous T-cell lymphoma: clinical synergism and possible immunologic mechanisms

BACKGROUND

For nearly 2 decades clinicians have been treating cutaneous T-cell lymphoma (CTCL) with regimens that combine interferon alfa with retinoid compounds. In December 1999 a new retinoid, bexarotene, was approved by the US Food and Drug Administration for the treatment of CTCL. At the manufacturer's recommended dose of bexarotene (300 mg/m(2) of body surface area), it has proven to be a highly effective therapy for all stages of CTCL. Nevertheless, this dose is typically associated with adverse effects including severe hyperlipidemia. Furthermore, there appears to be no standardization of dosing among physicians who treat CTCL.

OBSERVATIONS

We present 3 representative patients, 2 with erythrodermic CTCL and 1 with follicular mycosis fungoides, who experienced the rapid clearing of skin disease while being treated with a combination of low-dose bexarotene and low-dose recombinant interferon alfa.

CONCLUSIONS

Combining low-dose bexarotene with low-dose interferon alfa was well tolerated and led to rapid improvement in our patients. We review the clinical and biologic basis for this approach.

Topical and systemic retinoid therapy for cutaneous T-cell lymphoma

Because curative therapies for CTCL are not yet available, short of TSEB in patients who have early-stage disease and allogeneic bone marrow transplantation in patients who have more advanced disease, the goal of current therapies is to prevent progression of MF and to preserve quality of life. The overall conclusion drawn from the studies reported in the literature, is that retinoids as monotherapy, or in combination with other nonaggressive treatment modalities, represent a low-risk treatment alternative that is especially suitable for controlling early stages of MF and other CTCL. A combination of therapies may be more effective in controlling CTCL as shown with IFN-alpha plus retinoids, and, recently, IFN-alpha with bexarotene and other modalities. For example, isotretinoin, followed by TSEB (for stage I to II disease) or preceded by chemotherapy (for stage II and IV disease) and bexarotene plus PUVA or photopheresis plus IFN, gave overall response rates of 82% and 69% in patients who had MF and SS, respectively. Retinoids as monotherapy may induce complete remissions, but usually these responses are of short duration and relapses are common. Clinical response is not identical to histologic clearance. Even in cases with clinically complete clearance of skin lesions, lymphoid infiltrates persisted, which are most likely the source of recurrences. The new generation of retinoids, the RXR selective agonists like bexarotene, represent a promising approach for refractory or persistent MF that is unresponsive to first-line therapies. Individual differences in response to retinoids may be due to different expression of retinoid receptors, functional polymorphisms in metabolizing retinoids, or resistance to some retinoids. In the future, pharmacogenomic studies are needed to clarify the mechanisms that underlie the differing response rates of patients who have CTCL to retinoids. In addition, new agonists of RAR and RXR, either selective or pan agonists, will become available and will enlarge the spectrum of vitamin A analogs that have antitumoral properties.

Expression of nuclear retinoic acid receptor in peripheral blood mononuclear cells (PBMC) of healthy subjects

In vertebrates, both nuclear all-trans and 9-cis retinoic acid receptors (RAR and RXR) belonging to the steroid/thyroid/retinoid nuclear receptor superfamily play a crucial role in the vitamin A action. Qualitative analysis of all known RAR or RXR subtypes in both pooled and non-pooled peripheral blood mononuclear cells (PBMC) from healthy human subjects has been performed by reverse transcription and polymerase chain reaction (RT-PCR). Our data, based on qualitative RT-PCR analysis has shown that human PBMC are capable to express RAR alpha, RAR gamma, RXR alpha, and RXR beta.

New biologic agents for the treatment of cutaneous T-cell lymphoma

Cutaneous T-cell lymphoma (CTCL) is typically a skin-infiltrating malignancy of clonally derived CD4+ T lymphocytes. Because the host antitumor response appears to play an important role in disease control, systemic therapeutic agents are used in such a manner as to preserve the integrity of the host antitumor response while selectively targeting the malignant cells. The new biologic response-modifying treatment options currently used to treat CTCL are reviewed.

Increased serum immunoglobulin levels are common in mycosis fungoides and Sézary syndrome

BACKGROUND

Patients with cutaneous T-cell lymphoma (CTCL; mycosis fungoides [MF] and Sézary syndrome [SS]) acquire immunodeficiency and opportunistic infections.

OBJECTIVE

We attempted to determine whether abnormalities of humoral immunoglobulin levels are present.

METHODS

A retrospective analysis of serum immunoglobulin levels in patients with CTCL at baseline evaluation at a cancer center was compared to levels in patients with leukemias and levels in healthy control subjects.

RESULTS

A total of 254 of 650 patients with CTCL evaluated between 1987 and 2001 had baseline quantitative immunoglobulin levels. Mean IgG, IgA, and IgM levels were similar among all MF/SS patients versus controls. The percentages of MF/SS patients with elevated levels of each immunoglobulin class were higher than percentages in healthy controls, and elevated IgA levels occurred among late versus early patients (P =.043).

CONCLUSION

High immunoglobulin levels are more frequent in patients with MF and SS than in healthy controls, patients with chronic lymphocytic leukemia, and patients with hairy cell leukemia. High IgA levels are more frequent in late stage MF/SS.

Therapeutic advances in biological response modifiers in the treatment of cutaneous T-cell lymphoma

Cutaneous T-cell lymphoma (CTCL) is most often a skin-infiltrating malignancy of clonal CD4+ T-cells. Therapy is based on staging and the likelihood of progression. Biological response modifiers and chemotherapeutic agents are used to preserve the integrity of the host antitumour response while selectively targeting the malignant cells. The biological response-modifying treatment options currently used to treat CTCL are bexarotene, denileukin diftitox, interferon-alpha, interferon-gamma and interleukin-12, as well as extracorporeal photopheresis and phototherapy. A combination therapy approach maximises response in patients with advanced CTCL. Biological response modifiers in combination with photopheresis are used for patients with the leukaemic phase of the disease. Among the majority of patients with advanced stage disease so treated, immune response augmentation appears to prolong survival. Future areas of research should assess not only survival and optimal treatment combinations, but also quality of life during the treatment period.

Dysregulation of lymphocyte interleukin-12 receptor expression in Sézary syndrome

Initial phase I and II clinical trials with recombinant human interleukin-12 have demonstrated the therapeutic efficacy of this cytokine in early stage cutaneous T cell lymphoma as compared with more advanced stages such as the leukemic Sézary syndrome. In an effort to optimize the use of recombinant human interleukin-12, using flow cytometry we studied the regulation of the interleukin-12 receptor beta1 (high affinity chain) and beta2 (chain necessary for interleukin-12 signal transduction) on normal volunteer CD4+ and CD8+ T cells and CD4+ and CD8+ cells from eight patients with different degrees of leukemic involvement with Sézary syndrome. The beta1 chain was not readily detectable on resting normal and T cells from Sézary patients, but expression was induced following T cell activation with phytohemagglutinin. Similarly, the beta2 chain was not detectable on resting normal volunteer T cells, but could be induced following phytohemagglutinin stimulation. Moreover, the beta2 chain on normal volunteer T cells was markedly upregulated following short-term culture with interferon-gamma or recombinant human interleukin-12. CD8+ T cells routinely exhibited a greater expression of beta2 than did CD4+ T cells. In marked contrast, both CD4+ and CD8+ T cells from patients with Sézary syndrome and a high tumor cell burden (> 50% circulating atypical Sézary T cells) failed to express the beta2 chain under any culture conditions. Although, culture with anti-interleukin-10 also markedly increased beta2 expression on normal volunteer T cells, this failed to induce expression on either CD4+ or CD8+ T cells from Sézary patients and a high tumor burden. Investigation of patients with Sézary syndrome and a low tumor cell burden (< 15% circulating Sézary T cells) revealed a pattern of beta2 expression that was intermediate between advanced Sézary syndrome and normal volunteers. Both CD4+ and CD8+ peripheral blood T cells from these earlier stage patients were induced to express the beta2 chain, although at a lower frequency of positivity than T cells from normals, following culture with phytohemagglutinin, interferon-gamma, recombinant human interleukin-12, or anti-interleukin-10. These results indicate that short-term culture with interferon-gamma and recombinant human interleukin-12 potently upregulates beta2 chain expression on T cells from normal volunteers, whereas a similar, but less marked effect occurs on T cells from Sézary syndrome patients and a low circulating tumor cell burden. In contrast, the beta2 chain appears to be suppressed on both CD4+ and CD8+ T cells from Sézary patients with a heavy circulating tumor cell burden and it is not induced by interferon-gamma or recombinant human interleukin-12. Therefore, recombinant human interleukin-12 is likely to be most effective for early stage cutaneous T cell lymphoma due to a greater display of beta2 receptors on responding CD8+ anti-tumor cytotoxic T cells.

Bexarotene is effective and safe for treatment of refractory advanced-stage cutaneous T-cell lymphoma: multinational phase II-III trial results

PURPOSE

Cutaneous T-cell lymphomas (CTCL) are malignancies of T cells appearing as skin lesions and are responsive to retinoid therapy. Safety and efficacy of a novel RXR-selective retinoid (rexinoid) bexarotene (Targretin, LGD1069; Ligand Pharmaceuticals Inc, San Diego, CA) was evaluated as a single-agent oral therapy administered once daily in an open-label study in patients with refractory advanced-stage CTCL.

PATIENTS AND METHODS

Ninety-four patients with biopsy-confirmed CTCL in advanced stages (IIB-IVB) were enrolled at 26 centers. Fifty-six patients received an initial dose of 300 mg/m2/d oral bexarotene and 38 started at more than 300 mg/m2/d.

RESULTS

Clinical complete and partial responses were reported by Primary End point Classification for the study in 45% (25 of 56) of patients enrolled at 300 mg/m2/d dosing. At more than 300 mg/m2/d, 55% (21 of 38) of patients responded, including 13% (five of 38) clinical complete. For the 300 mg/m2/d initial dose group, the rate of relapse after response was 36% and the projected median duration of response was 299 days. Improvements were also seen in overall body-surface area involvement, median index lesion surface area, adenopathy, cutaneous tumors, pruritus, and CTCL-specific quality of life. The most frequent drug-related adverse events included hypertriglyceridemia (associated rarely with pancreatitis), hypercholesterolemia, hypothyroidism, and headache.

CONCLUSION

Bexarotene is the first in a novel class of pharmacologic agents, the RXR-selective retinoids, or rexinoids. Bexarotene is orally administered, safe, and generally well tolerated with reversible side effects, and is effective for the treatment of advanced, refractory CTCL.

Treatment of cutaneous T-cell lymphoma from a dermatologist's perspective

Mycosis fungoides, the most common form of cutaneous T-cell lymphoma, is a helper/memory epidermotrophic T-cell lymphoma presenting as skin lesions. At the current time, curative therapy does not exist, and many patients have chronic skin lesions for many years, with successful treatment limited to the skin. Mycosis fungoides appears to start as a human lymphocyte antigen-restricted immune response, which may be antigen or superantigen driven, in early stages. From a dermatologist's perspective, removing the stimulating antigen(s), treating infections, preserving the skin barrier, targeting the abnormal clone, preserving the cytotoxic response, and using skin-directed therapy early in the disease are sensible strategies. As the disease progresses to involve more of the skin surface, systemic therapies, especially biological response modifiers (interferon and retinoids), phototherapy, or photopheresis help to preserve the patient's innate immunity and are widely used. New agents including bexarotene (a rexinoid) and DAB(389)IL-2 (interleukin-2 diphtheria fusion protein) offer new therapeutic options that are advantageous for treatment of mycosis fungoides in later stages.

Impairment of STAT activation by IL-12 in a patient with atypical mycobacterial and staphylococcal infections

IL-12 plays a pivotal role in the stimulation of immune responses against intracellular infections. This role is manifested in the increased susceptibility to atypical mycobacterial and salmonella infections among individuals whose lymphocytes lack expression of IL-12Rbeta1. Here, we report on a patient with Mycobacterium avium infection, recurrent Staphylococcus aureus sinusitis, and multiple adverse drug reactions whose T cells were unable to produce IFN-gamma or proliferate in response to IL-12 despite the expression of wild-type IL-12Rbeta1 and IL-12Rbeta2. The defect in these functional responses to IL-12 was selective, as cytolytic activity induced by IL-12 was intact, and lymphocytes were responsive to stimulation by IL-2. An examination of cytokine signaling revealed that STAT4 and extracellular regulated kinase 1 (ERK1) activation by IL-12 was intact, whereas the activation of STAT1, -3, and -5 by IL-12 was lost. This impairment of STAT activation was specific for IL-12, as STAT activation by IL-2, IL-15, and IFN-gamma was unaffected. These findings demonstrate that the activation of STAT4 alone is not sufficient for IL-12-induced IFN-gamma production and proliferation and suggest that other STATs play a role in these responses to IL-12. While the etiology of the impaired IL-12 signaling in this patient has not yet been elucidated, the absence of mutations in IL-12Rbeta1 or IL-12Rbeta2 and the preservation of STAT4 activation raise the possibility that there may be a mutation in an as yet undiscovered component of the IL-12 signaling complex that is normally required for the recruitment and activation of STAT1, -3, and -5.

Emerging new therapies for cutaneous T-cell lymphoma

Improved therapy for CTCL will depend on a better understanding of the pathogenesis of this disease at a molecular level. It is clear that the T cells in MF and CTCL do not undergo normal programmed cell death and have prolonged lifespans. Skin flora or other antigens may stimulate the initial proliferation, offering another approach to change the course of the disease. There has been tremendous interest in biological response modifiers, and the first targeted fusion toxin to activated T cells has been approved for CTCL. New retinoids with increased selectivity and decreased side effects are being tested for this disease. In summary, the treatment of CTCL should continue to improve and should be focused on strategies that preserve the immune function in these patients.