Pityriasis lichenoid-like mycosis fungoides

Sir, Mycosis fungoides is a primary cutaneous T–cell lymphoma, secondary clonal proliferation of mature skin-homing T cells, mostly CD4-positive, with a predilection for involving the epidermis. It is an indolent lymphoma that progresses over several years and represents 50% of primary cutaneous T-cell lymphomas [1]. Its clinical presentation is variable, thus leading to several clinical variants. Herein, we describe a rare variant of mycosis fungoides: pityriasis lichenoid-like mycosis fungoides. A 45-year-old female was referred to our department with a papular rash evolving for the last year without regression. The patient had a history of breast carcinoma in complete remission for two years. A clinical examination revealed erythematous, scaly, non-itchy papules covering the entire body but sparing the face (Figs. 1 and 2). There was no scalp involvement or associated lymphadenopathy. Based on the clinical presentation, the suggested diagnosis was pityriasis lichenoid. A histological examination revealed Pautrier’s microabscesses, atypical lymphocyte infiltration along the basal layer and papillary dermis, and prominent epidermotropism (Fig. 3). There was pilotropism without mucin. Besides, hyperkeratosis with focal parakeratosis and perivascular infiltrate were noted. An immunohistochemical analysis revealed infiltrates of T cells expressing CD3, CD2, CD5, and a predominance of CD4-positive T cells in the epidermis compared to CD8-positive T cells. CD7 and CD30 were, however, negative. These findings were consistent with pityriasis lichenoid-like mycosis fungoides. The patient was classified as a IB stage and received UVB phototherapy with good progress.

Macrophage-derived CXCL9 and CXCL11, T-cell skin homing and disease control in mogamulizumab-treated CTCL patients

Cutaneous T-cell lymphoma (CTCL) is a malignancy of skin-homing T-cells. Long-term remissions are rare in CTCL, and the pathophysiology of long-lasting disease control is unknown. Mogamulizumab is a defucosylated anti-human CCR4 antibody that depletes CCR4-expressing CTCL tumor cells and peripheral blood memory regulatory T cells. Prolonged remissions and immune side effects have been observed in mogamulizumab-treated CTCL patients. We report that mogamulizumab induced skin rashes in 32% of 44 CTCL patients. These rashes were associated with long-term CTCL remission, even in the absence of specific CTCL treatment. CTCL patients with mogamulizumab-induced rash had significantly higher overall survival (hazard ratio, 0.16 (0.04-0.73, p=0.01)). Histopathology and immunohistochemistry of the rashes revealed granulomatous and lichenoid patterns with CD163 macrophagic and CD8 T-cell infiltrates. Depletion of skin CTCL cells was confirmed by high-throughput sequencing analysis of TCRβ genes and in blood by flow cytometry. New reactive T-cell clones were recruited in skin. Gene expression analysis showed overexpression of CXCL9 and CXCL11, two chemokines involved in CXCR3-expressing T-cell homing to skin. Single-cell RNA sequencing analysis in skin of CTCL patients confirmed that CXCL9 and CXCL11 were primarily macrophage-derived and that skin T-cells expressed CXCR3. Finally, patients with rashes had a significantly higher proportion of exhausted reactive blood T-cells expressing TIGIT and PD1 at baseline compared to patients without rash, which decreased under mogamulizumab treatment, consistent with an activation of the antitumor immunity. Together, these data suggest that mogamulizumab may induce long-term immune control in CTCL patients by activation of the macrophagic and T-cell immune responses.

T cell receptor sequencing specifies psoriasis as a systemic and atopic dermatitis as a skin-focused, allergen-driven disease

Atopic dermatitis (AD) and psoriasis represent two of the most common inflammatory skin diseases in developed countries. A hallmark of both diseases is T cell infiltration into the skin. However, it is still not clarified to what extent these infiltrating T cells are antigen-specific skin-homing T cells or unspecific heterogeneous bystander cells. To elucidate this, T cells from lesional skin and from blood of 10 AD and 11 psoriasis patients were compared by receptor (TCR) sequencing. Therefore, peripheral blood mononuclear cells (PBMC) were cell-sorted according to expression of the cutaneous leukocyte antigen (CLA) into skin-homing (CLA+) and non-skin-homing (CLA-) subfractions. Aeroallergen-specific T cell lines were grown from AD patients' PBMC in parallel. Intra-individual comparison of TCRB CDR3 regions revealed that clonally expanded T cells in skin lesions of both AD and psoriasis patients corresponded to skin-homing circulating T cells. However, in psoriasis patients, these T cell clones were also detectable to a larger extent among CLA- circulating T cells. Up to 28% of infiltrating cells were identified as allergen-specific by overlapping TCR sequences. Our data shows that in line with the systemic nature of psoriasis, T cells infiltrating psoriatic skin lesions do not exclusively home to the skin and are therefore not specific to antigens that are exclusively encountered at the skin. T cells driving AD skin inflammation appear to home nearly exclusively to the skin and are, to a certain extent, specific to aeroallergens.

Potent Anticancer Effects of Epidithiodiketopiperazine NT1721 in Cutaneous T Cell Lymphoma

Cutaneous T cell lymphomas (CTCLs) are a heterogeneous group of debilitating, incurable malignancies. Mycosis fungoides (MF) and Sézary syndrome (SS) are the most common subtypes, accounting for ~65% of CTCL cases. Patients with advanced disease have a poor prognosis and low median survival rates of four years. CTCLs develop from malignant skin-homing CD4+ T cells that spread to lymph nodes, blood, bone marrow and viscera in advanced stages. Current treatments options for refractory or advanced CTCL, including chemotherapeutic and biological approaches, rarely lead to durable responses. The exact molecular mechanisms of CTCL pathology remain unclear despite numerous genomic and gene expression profile studies. However, apoptosis resistance is thought to play a major role in the accumulation of malignant T cells. Here we show that NT1721, a synthetic epidithiodiketopiperazine based on a natural product, reduced cell viability at nanomolar concentrations in CTCL cell lines, while largely sparing normal CD4+ cells. Treatment of CTCL cells with NT1721 reduced proliferation and potently induced apoptosis. NT1721 mediated the downregulation of GLI1 transcription factor, which was associated with decreased STAT3 activation and the reduced expression of downstream antiapoptotic proteins (BCL2 and BCL-xL). Importantly, NT1721, which is orally available, reduced tumor growth in two CTCL mouse models significantly better than two clinically used drugs (romidepsin, gemcitabine). Moreover, a combination of NT1721 with gemcitabine reduced the tumor growth significantly better than the single drugs. Taken together, these results suggest that NT1721 may be a promising new agent for the treatment of CTCLs.

CLINICAL, IMAGING AND PATHOLOGICAL ASPECTS OF MAMMARY LYMPHOMAS SECONDARY TO MALIGNANT T- CELL CUTANEOUS LYMPHOMAS

Primary cutaneous lymphomas rank as the second most common clinical form of extranodal non-Hogdkin malignant lymphomas. Among non-Hodgkin malignant skin T-cell lymphomas, Mycosis Fungoides (MF) is the most frequent clinical occurence. The MF lymphoma originates in skin-homing helper T-cells, which express the CD4 + marker, showing chronic evolution, with recurrent lesions. In advanced stages, patients with Mycosis Fungoides may experience severe/extensive skin lesions or extracutaneous localizations of the disease. The secondary breast lymphoma is more common in non-Hodgkin malignant lymphoma than in Hodgkin lymphoma. Among the mammographic characteristics of breast lymphoma we mention: oval or round tumor mass, with well-defined or indistinct margins, absence of intratumoral calcifications, presence of intramammary lymph nodes, supra-adjacent skin thickening and lymphedema that causes diffuse increase in breast density. The ultrasound features of breast lymphoma run as follows: it is oval or round in shape, with well-defined or indistinct margins, which in Doppler ultrasound are identified as hypervascularized masses. The description of the imaging features of mammary lymphomas secondary to cutaneous T-cell lymphomas is required before performing the breast core-needle biopsy.

P033 Dendritic cells from patients with active IBD imprint pro-inflammatory α4β7+CLA+ T cells with potential for gut and skin homing

Background T cell trafficking contributes to inflammation and is a therapeutic target in IBD. Exposure of T cells to retinoic acid during activation induces expression of the gut trafficking integrin α4β7 and suppresses expression of cutaneous leukocyte antigen (CLA) which is required for entry into the skin. Although α4β7+ (gut homing) and CLA+ (skin homing) T cells are generally non-overlapping populations, we have recently observed a low frequency of α4β7+CLA+ (dual tropic) T cells in human blood; these cells may provide an immunological link between gut and skin. Here we investigate the generation of these population by DC in vitro, analyse the function of cells with different tissue tropism and examine the impact of intestinal and skin inflammation. Methods Using flow cytometry, expression of α4β7 and CLA was assessed in whole blood, gut tissues, and on proliferating cells generated by stimulation of naïve CD4+ T cells with monoclonal antibodies (anti-CD3/28/2), or with allogeneic colonic or monocyte-derived DC (moDC). Production of TNFα and IFNγ was measured by intracellular cytokine staining. Results α4β7+CLA+ T cells were found at low frequency in ileal lamina propria tissue as well as peripheral blood. Naïve CD4 T cells activated in vitro with antibodies expressed α4β7 but not CLA. In contrast, activation with DC resulted in the expression of both α4β7 and CLA and generated a dual tropic a4b7+CLA+ population. Colonic DC generated significantly more α4β7+ cells (p<0.05) and higher levels of α4β7 (p<0.05) than did moDC; colonic DC generated significantly fewer CLA+ cells (p<0.01). Nonetheless, a similar frequency of dual tropic cells was generated by both types of DC. moDC from healthy controls and patients with active IBD or skin inflammation all generated dual tropic cells. moDC from patients with active IBD, but not from patients with active inflammatory skin disease generated more gut tropic (α4β7+) T cells (p<0.05) compared with moDC from healthy controls. Following activation with moDC, cytokine production varied with homing profile. The frequency of TNFα+ and IFNg+ cells was significantly greater in CLA+ expressing populations (p<0.05 and p<0.01, respectively). Conclusion CLA expression is induced by gut DC even though they potently upregulate α4β7. The dual tropic population generated is enriched for cells that produce inflammatory cytokines and it may provide a link between gut and skin inflammation. Monocyte-derived cells may contribute to the imprinting of T cell homing to the intestine and upregulation of this activity, specifically in active IBD, supports the concept that intestinal inflammation reprogrammes circulating monocytes.

Normal and Cancer Fibroblasts Differentially Regulate Cytokine Genes and TWIST1 and TOX Expression in Cutaneous T-cell Lymphoma

Background: Mycosis fungoides (MF) is a primary cutaneous T-cell lymphoma (CTCL) that transforms from mature, skin-homing T cells and progresses in the skin. The role of the skin microenvironment in MF development is unclear, but recent findings in a variety of cancers have highlighted the role of stromal fibroblasts in promoting or inhibiting tumorigenesis. Stromal fibroblast are an important part of the cutaneous tumor microenvironment (TME) in MF. Here we describe studies into the interaction of TME-fibroblasts and malignant T cells to gain insight into their role in CTCL.Methods: Myla cell is a CTCL cell line that retains expression of biomarkers TWIST1 and TOX that are frequently detected in CTCL patients. MyLa cells were cultured in the presence or absence of normal or MF skin derived fibroblasts for 5 days, trypsinized to detached Myla cells, and gene expression analyzed by RT-PCR for MF biomarkers (TWIST1 and TOX), Th1 markers (IFN-g, TBX21), Th2 markers (GATA3, IL-16), and proliferation marker (MKI67). Purified fibroblasts were assayed for expressed genes VIM and ACTA2. Cellular senescence assay was performed to assess senescence.Results: Normal fibroblasts co-cultured with MyLa cells suppressed expression of the CTCL biomarkers TWIST1 (p < 0.0006) and TOX (p<0.03) in MyLa cells . In contrast, MyLa cells cultured with MF fibroblasts retained high expression of TWIST1 and TOX. Normal fibroblasts increased expression of IFN-g (p < 0.03) and TBX21, and decreased expression of GATA3 (p < 0.02) and IL-16 (p < 0.03) in MyLa cells, whereas MF fibroblasts suppressed IFN-g and TBX21 and increased TWIST1 and TOX expression in MyLa cells. Furthermore, expression of MKI67 in MyLa cells was suppressed to a greater degree by normal fibroblasts compared to MF fibroblasts. Conclusions: Skin fibroblasts represent important components of the microenvironment in MF. In co-culture model, normal and cancer fibroblasts in MF have differential influence on T cell phenotype in modulating expression of Th1 cytokine and CTCL biomarker genes to reveal distinct role with implications in MF progression.