Bernice M. Benoit

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.

Increased Programmed Death-1 Expression on CD4+ T Cells in Cutaneous T-Cell Lymphoma: Implications for Immune Suppression

OBJECTIVES To investigate the expression profile of programmed death-1 (PD-1) on T cells derived from patients with cutaneous T-cell lymphoma (CTCL), analyze a potential mechanism responsible for upregulation of PD-1, and assess the correlation between blockade of its signaling pathway and improvement in immunological function. DESIGN Translation research study. SETTING University medical center. PARTICIPANTS Patients with Sézary syndrome, patients with mycosis fungoides, and healthy volunteers. MAIN OUTCOME MEASURES Programmed death-1 expression on T cells by flow cytometry and interferon γ (IFN-γ) production by enzyme-linked immunosorbent assay. RESULTS We report significantly increased PD-1 expression on CD4(+) T cells from patients with Sézary syndrome compared with CD4(+) T cells from patients with mycosis fungoides and healthy volunteers. Both CD26(-) and CD26(+) populations of CD4(+) T cells demonstrated increased expression of PD-1, which was upregulated by the engagement of the T-cell receptor with anti-CD3/CD28 antibodies. In addition, blockade of the signaling pathway with blocking antibodies to PD-1 or its ligand PD-L1 led to an increase in the capacity to produce IFN-γ among some patients. Finally, longitudinal studies of 1 patient revealed a progressive decrease in PD-1 expression on CD4(+) T cells with improvement of clinical disease. CONCLUSION Our data imply that increased PD-1 expression in Sézary syndrome may play a role in attenuating the immune response and provide further insight into the immunosuppressive nature of CD4(+) T cells in Sézary syndrome and suggest another potential means of targeted therapy for these patients.

Biological Effects of Bexarotene in Cutaneous T-Cell Lymphoma

OBJECTIVES To delineate the natural history of pityriasis rosea in black children and to compare our findings with those of the American, European, and African literature on pityriasis rosea. Textbook and journal article descriptions of pityriasis rosea usually offer information about the presentation and clinical course of this condition in white patients. DESIGN Prospective observational study. SETTING The general pediatric clinic, adolescent clinic, and emergency department of Childrens Hospital of Michigan, Detroit, from June 2003 through May 2005. PATIENTS We followed up 50 black children with pityriasis rosea from the time of diagnosis through follow-up visits at 1, 2, and 4 weeks. Detailed observations were made and digital photographs taken at each visit. MAIN OUTCOME MEASURES Duration of illness and pigmentary sequelae. RESULTS Similarities with the medical literature were found regarding season of onset and prevalence of pruritus and of a herald patch. Our patients had more frequent facial involvement (30%) and more scalp lesions (8%) than usually described in white populations. One third had papular lesions. The disease resolved in nearly one half of patients within 2 weeks. Residual hyperpigmentation was seen in 48% of patients. Hypopigmentation developed in 29% of patients with purely papular or papulovesicular lesions. CONCLUSIONS Pityriasis rosea in black children differs in several ways from textbook descriptions. Physicians may use this information to better counsel patients about the course and potential sequelae of this condition.

Topical resiquimod can induce disease regression and enhance T-cell effector functions in cutaneous T-cell lymphoma.

Early-stage cutaneous T-cell lymphoma (CTCL) is a skin-limited lymphoma with no cure aside from stem cell transplantation. Twelve patients with stage IA-IIA CTCL were treated in a phase 1 trial of 0.03% and 0.06% topical resiquimod gel, a Toll-like receptor 7/8 agonist. Treated lesions significantly improved in 75% of patients and 30% had clearing of all treated lesions. Resiquimod also induced regression of untreated lesions. Ninety-two percent of patients had more than a 50% improvement in body surface area involvement by the modified Severity-Weighted Assessment Tool analysis and 2 patients experienced complete clearing of disease. Four of 5 patients with folliculotropic disease also improved significantly. Adverse effects were minor and largely skin limited. T-cell receptor sequencing and flow cytometry studies of T cells from treated lesions demonstrated decreased clonal malignant T cells in 90% of patients and complete eradication of malignant T cells in 30%. High responses were associated with recruitment and expansion of benign T-cell clones in treated skin, increased skin T-cell effector functions, and a trend toward increased natural killer cell functions. In patients with complete or near eradication of malignant T cells, residual clinical inflammation was associated with cytokine production by benign T cells. Fifty percent of patients had increased activation of circulating dendritic cells, consistent with a systemic response to therapy. In summary, topical resiquimod is safe and effective in early-stage CTCL and the first topical therapy to our knowledge that can induce clearance of untreated lesions and complete remissions in some patients. This trial was registered at www.clinicaltrials.gov as #NCT813320.

Improved pruritus correlates with lower levels of IL-31 in CTCL patients under different therapeutic modalities.

Pruritus is one of the cardinal symptoms found in patients with leukemic cutaneous T cell lymphoma (CTCL). The nature of the pruritus experienced by CTCL patients is complex, involving different pathways and cell mediators, thus making it poorly responsive to conventional anti-itch therapies. Recent reports highlight the role of interleukin 31 (IL-31) as a novel cytokine involved in the pathogenesis of pruritus in atopic dermatitis and CTCL. Here we provide both in vivo and in vitro evidence suggesting that histone deacetylase (HDAC) inhibitors may mitigate itch through lowering of levels of IL-31-expressing T cells. Furthermore, we demonstrate that chemokine receptor type-4 (CCR4)-bearing T cells are a main source of IL-31 in CTCL, and that neutralizing the IL-31 pathway through targeting of the CCR4-expressing T cells may represent a promising therapeutic strategy for symptomatic relief in CTCL.

CD164 and FCRL3 Are Highly Expressed on CD4+CD26 − T Cells in Sézary Syndrome Patients

Sézary syndrome (SS) cells express cell surface molecules also found on normal activated CD4 T cells. In an effort to find a more specific surface marker for malignant SS cells, a microarray analysis of gene expression was performed. Results showed significantly increased levels of mRNA for CD164, a sialomucin found on human CD34+ hematopoietic stem cells, and FCRL3, a molecule present on a subset of human natural T regulatory cells. Both markers were increased in CD4 T cells from SS patients compared to healthy donors. Flow cytometry studies confirmed the increased expression of CD164 and FCRL3 primarily on CD4+CD26− T cells of SS patients. Importantly, a statistically significant correlation was found between an elevated percentage of CD4+CD164+ T cells and an elevated percentage of CD4+CD26− T cells in all tested SS patients but not in patients with Mycosis Fungoides and atopic dermatitis or healthy donors. FCRL3 expression was significantly increased only in high tumor burden patients. CD4+CD164+ cells displayed cerebriform morphology and their loss correlated with clinical improvement in treated patients. Our results suggest that CD164 can serve as a marker for diagnosis and for monitoring progression of CTCL/SS and that FCRL3 expression correlates with a high circulating tumor burden.

Synergistic enhancement of cellular immune responses by the novel Toll receptor 7/8 agonist 3M-007 and interferon-γ: implications for therapy of cutaneous T-cell lymphoma

Abstract Cutaneous T-cell lymphoma (CTCL) is responsive at all stages to immunotherapy. We determined whether a novel agonist for Toll-like receptor (TLR) 7/8 (3M-007) combined with either interferon-γ (IFN-γ) or interleukin-15 (IL-15) would enhance patients’ immune responses in vitro. Our data demonstrate that IFN-γ or IL-15 in combination with 007 significantly increases patients’ natural killer (NK) cytolytic activity against CTCL tumor cell lines and synergistically induces dendritic cell cytokines, compared to 007 alone. Microarray studies of gene expression of patients’ peripheral blood mononuclear cells (PBMCs) primed with IFN-γ followed by stimulation with 007 identified significant up-regulation of the expression of IL-12 p35 (α-chain), IL-12 p40 (β-chain), and nine IFN-α genes. Importantly, the underlying mechanism of increased levels of IFN-α and IL-12 from combined treatment appears to involve IFN regulatory factor 8 (IRF-8). These results further support our hypothesis that combinations of biological modifiers activating different arms of the immune system may provide significant therapeutic benefits for patients with advanced CTCL.

Inhibition of cell-mediated immunity by the histone deacetylase inhibitor vorinostat: Implications for therapy of cutaneous T-cell lymphoma†

Several histone deacetylase inhibitors (HDACi), including vorinostat, have been approved for the therapy of cutaneous T-cell lymphoma (CTCL). Emerging data suggest that HDACi may exert immune suppressive effects which would be disadvantageous for therapy of CTCL. We describe a patient with Sezary syndrome who was monitored for drug-induced immunosuppression while undergoing treatment with vorinostat. Analysis of the patients natural killer cell function before and after initiation of treatment confirmed inhibition of this important cell-mediated immune function. In addition, the in vitro effects of vorinostat on the immunity of healthy volunteers confirmed that this class of drug can profoundly suppress multiple arms of the cellular immune response. These findings raise concerns of increased susceptibility to infection in this high-risk population.

Clinical and in vitro resistance to bexarotene in adult T cell leukemia: loss of RXR-alpha receptor

The oral rexinoid bexarotene (Targretin) is widely used for treatment of cutaneous T-cell lymphomas (CTCL). We recently reported the first case of adult T-cell leukemia/lymphoma (ATLL) that responded rapidly to combination therapy of bexarotene and interferon (IFN)-alpha2b with complete clinical response. We demonstrated that bexarotene induced apoptosis of the patients malignant peripheral blood T-cells in vitro. However, our patient developed skin and nodal relapse 180 days after starting treatment. We now demonstrate that his peripheral blood malignant T cells became resistant to bexarotene-induced apoptosis. We investigated potential mechanisms that may cause aberrations in the retinoid X receptor (RXR) subunits, RXR-alpha and RXR-beta, to account for these findings. Sequence analysis did not reveal acquisition of mutations in the genes encoding RXR-alpha and RXR-beta by resistant cells. We assessed RXR-alpha and RXR-beta expression by Western blot analysis and found that resistant cells had significantly decreased RXR-alpha expression compared with pretherapy bexarotene-sensitive cells. Our findings indicate that reduced expression of the RXR-alpha receptor subunit may represent a mechanism for resistance to bexarotene in T-cell malignancies.

The use of cytokines, fusion proteins and antibodies to treat cutaneous T‐cell lymphoma

ABSTRACT:  It has long been known that certain immune augmenting therapeutics, particularly interferon alpha, can exert profound salutary effects on the clinical progress of patients with cutaneous T‐cell lymphoma. Emerging evidence that the host immune response may play an important role in the control of this disorder has led to the clinical application of other cytokines including interleukin‐12 and interferon gamma. In this review, the authors will summarize current knowledge regarding the use of cytokines, fusion proteins and antibodies for the treatment of cutaneous T‐cell lymphoma.