Bacterial toxins fuel disease progression in cutaneous T-cell lymphoma

Keratinocytes Present Staphylococcus aureus Enterotoxins and Promote Malignant and Nonmalignant T Cell Proliferation in Cutaneous T-Cell Lymphoma

Cutaneous T-cell lymphoma is characterized by malignant T cells proliferating in a unique tumor microenvironment dominated by keratinocytes (KCs). Skin colonization and infection by Staphylococcus aureus are a common cause of morbidity and are suspected of fueling disease activity. In this study, we show that expression of HLA-DRs, high-affinity receptors for staphylococcal enterotoxins (SEs), by KCs correlates with IFN-γ expression in the tumor microenvironment. Importantly, IFN-γ induces HLA-DR, SE binding, and SE presentation by KCs to malignant T cells from patients with Sézary syndrome and malignant and nonmalignant T-cell lines derived from patients with Sézary syndrome and mycosis fungoides. Likewise, preincubation of KCs with supernatant from patient-derived SE-producing S aureus triggers proliferation in malignant T cells and cytokine release (including IL-2), when cultured with nonmalignant T cells. This is inhibited by pretreatment with engineered bacteriophage S aureus-specific endolysins. Furthermore, alteration in the HLA-DR-binding sites of SE type A and small interfering RNA-mediated knockdown of Jak3 and IL-2Rγ block induction of malignant T-cell proliferation. In conclusion, we show that upon exposure to patient-derived S aureus and SE, KCs stimulate IL-2Rγ/Jak3-dependent proliferation of malignant and nonmalignant T cells in an environment with nonmalignant T cells. These findings suggest that KCs in the tumor microenvironment play a key role in S aureus-mediated disease activity in cutaneous T-cell lymphoma.

Staphylococcus aureus induces drug resistance in cancer T cells in Sézary syndrome

ABSTRACT

Patients with Sézary syndrome (SS), a leukemic variant of cutaneous T-cell lymphoma (CTCL), are prone to Staphylococcus aureus infections and have a poor prognosis due to treatment resistance. Here, we report that S aureus and staphylococcal enterotoxins (SE) induce drug resistance in malignant T cells against therapeutics commonly used in CTCL. Supernatant from patient-derived, SE-producing S aureus and recombinant SE significantly inhibit cell death induced by histone deacetylase (HDAC) inhibitor romidepsin in primary malignant T cells from patients with SS. Bacterial killing by engineered, bacteriophage-derived, S aureus-specific endolysin (XZ.700) abrogates the effect of S aureus supernatant. Similarly, mutations in major histocompatibility complex (MHC) class II binding sites of SE type A (SEA) and anti-SEA antibody block induction of resistance. Importantly, SE also triggers resistance to other HDAC inhibitors (vorinostat and resminostat) and chemotherapeutic drugs (doxorubicin and etoposide). Multimodal single-cell sequencing indicates T-cell receptor (TCR), NF-κB, and JAK/STAT signaling pathways (previously associated with drug resistance) as putative mediators of SE-induced drug resistance. In support, inhibition of TCR-signaling and Protein kinase C (upstream of NF-κB) counteracts SE-induced rescue from drug-induced cell death. Inversely, SE cannot rescue from cell death induced by the proteasome/NF-κB inhibitor bortezomib. Inhibition of JAK/STAT only blocks rescue in patients whose malignant T-cell survival is dependent on SE-induced cytokines, suggesting 2 distinct ways SE can induce drug resistance. In conclusion, we show that S aureus enterotoxins induce drug resistance in primary malignant T cells. These findings suggest that S aureus enterotoxins cause clinical treatment resistance in patients with SS, and antibacterial measures may improve the outcome of cancer-directed therapy in patients harboring S aureus.

Rare COVID-19 vaccine side effects got lost in the shuffle. Primary cutaneous lymphomas following COVID-19 vaccination: a systematic review

Introduction

COVID-19 vaccines are generally safe and effective; however, they are associated with various vaccine-induced cutaneous side effects. Several reported cases of primary cutaneous lymphomas (CLs) following the COVID-19 vaccination have raised concerns about a possible association. This systematic review aims to investigate and elucidate the potential link between CLs and SARS-CoV-2 vaccines.

Methods

We performed a systematic literature search on PubMed, EBSCO and Scopus from January 01, 2019, to March 01, 2023, and analyzed studies based on determined eligibility criteria. The systematic review was performed based on the PRISMA protocol.

Results

A total of 12 articles (encompassing 24 patients) were included in this analysis. The majority of CLs were indolent cutaneous T-cell lymphomas (CTCLs) (66,7%; 16/24), with Lymphomatoid papulosis (LyP) being the most common type (33,3%; 8/24). Most patients (79,2%; 19/24) developed lesions after receiving the COVID-19 mRNA-based vaccines, and predominantly after the first immunization dose (54,2%; 13/24). The presented CLs cases exhibited a tendency to exacerbate following subsequent COVID-19 vaccinations. Nevertheless, CLs were characterized by a favorable course, leading to remission in most cases.

Conclusion

The available literature suggests an association between the occurrence and exacerbation of CLs with immune stimulation following COVID-19 vaccination. We hypothesize that post-vaccine CLs result from an interplay between cytokines and disrupted signaling pathways triggered by vaccine components, concurrently playing a pivotal role in the pathomechanism of CLs. However, establishing a definitive causal relationship between these events is currently challenging, primarily due to the relatively low rate of reported post-vaccine CLs. Nonetheless, these cases should not be disregarded, and patients with a history of lymphoproliferative disorders require post-COVID-19 vaccination monitoring to control the disease's course.Systematic review registrationwww.researchregistry.com, identifier [1723].

Modulation of the skin microbiome in cutaneous T-cell lymphoma delays tumour growth and increases survival in the murine EL4 model

Cutaneous T-cell lymphomas (CTCL) are a group of lymphoproliferative disorders of skin-homing T cells causing chronic inflammation. These disorders cause impairment of the immune environment, which leads to severe infections and/or sepsis due to dysbiosis. In this study, we elucidated the host-microbial interaction in CTCL that occurs during the phototherapeutic treatment regime and determined whether modulation of the skin microbiota could beneficially affect the course of CTCL. EL4 T-cell lymphoma cells were intradermally grafted on the back of C57BL/6 mice. Animals were treated with conventional therapeutics such as psoralen + UVA (PUVA) or UVB in the presence or absence of topical antibiotic treatment (neomycin, bacitracin, and polymyxin B sulphate) as an adjuvant. Microbial colonisation of the skin was assessed to correlate with disease severity and tumour growth. Triple antibiotic treatment significantly delayed tumour occurrence (p = 0.026), which prolonged the survival of the mice (p = 0.033). Allocation to phototherapeutic agents PUVA, UVB, or none of these, along with antibiotic intervention, reduced the tumour growth significantly (p = 0.0327, p ≤ 0.0001, p ≤ 0.0001 respectively). The beta diversity indices calculated using the Bray-Curtis model showed that the microbial population significantly differed after antibiotic treatment (p = 0.001). Upon modulating the skin microbiome by antibiotic treatment, we saw an increase in commensal Clostridium species, e.g., Lachnospiraceae sp. (p = 0.0008), Ruminococcaceae sp. (p = 0.0001)., Blautia sp. (p = 0.007) and a significant reduction in facultative pathogens Corynebacterium sp. (p = 0.0009), Pelomonas sp. (p = 0.0306), Streptococcus sp. (p ≥ 0.0001), Pseudomonas sp. (p = 0.0358), and Cutibacterium sp. (p = 0.0237). Intriguingly, we observed a significant decrease in Staphylococcus aureus frequency (p = 0.0001) but an increase in the overall detection frequency of the Staphylococcus genus, indicating that antibiotic treatment helped regain the microbial balance and increased the number of non-pathogenic Staphylococcus populations. These study findings show that modulating microbiota by topical antibiotic treatment helps to restore microbial balance by diminishing the numbers of pathogenic microbes, which, in turn, reduces chronic inflammation, delays tumour growth, and increases survival rates in our CTCL model. These findings support the rationale to modulate the microbial milieu during the disease course of CTCL and indicate its therapeutic potential.

Role of Antigenic Stimulation in Cutaneous T-Cell Lymphomas

Cutaneous T-cell lymphoma (CTCL) involves a clonal expansion of malignant cells accumulating in the skin, a primary barrier site. CTCL has long been hypothesized to be caused or perpetuated by chronic antigen stimulation due to unknown exposures. These antigenic triggers, defined as any element that may cause activation of malignant T cells through TCR signaling, have been hypothesized to range from chemicals to microbes. This review covers current evidence supporting chemical and microbial stimuli that may act as antigenic triggers of CTCL and summarizes novel areas of investigation, in which the potential antigenicity of the exposure is still unknown.

Vitamin D in Cutaneous T-Cell Lymphoma

Cutaneous T-cell lymphoma (CTCL) is characterized by the proliferation of malignant T cells in inflamed skin lesions. Mycosis fungoides (MF)-the most common variant of CTCL-often presents with skin lesions around the abdomen and buttocks ("bathing suit" distribution), i.e., in skin areas devoid of sun-induced vitamin D. For decades, sunlight and vitamin D have been connected to CTCL. Thus, vitamin D induces apoptosis and inhibits the expression of cytokines in malignant T cells. Furthermore, CTCL patients often display vitamin D deficiency, whereas phototherapy induces vitamin D and has beneficial effects in CTCL, suggesting that light and vitamin D have beneficial/protective effects in CTCL. Inversely, vitamin D promotes T helper 2 (Th2) cell specific cytokine production, regulatory T cells, tolerogenic dendritic cells, as well as the expression of immune checkpoint molecules, all of which may have disease-promoting effects by stimulating malignant T-cell proliferation and inhibiting anticancer immunity. Studies on vitamin D treatment in CTCL patients showed conflicting results. Some studies found positive effects, others negative effects, while the largest study showed no apparent clinical effect. Taken together, vitamin D may have both pro- and anticancer effects in CTCL. The balance between the opposing effects of vitamin D in CTCL is likely influenced by treatment and may change during the disease course. Therefore, it remains to be discovered whether and how the effect of vitamin D can be tilted toward an anticancer response in CTCL.

Endolysin Inhibits Skin Colonization by Patient-Derived Staphylococcus Aureus and Malignant T-Cell Activation in Cutaneous T-Cell Lymphoma

Staphylococcus aureus is suspected to fuel disease activity in cutaneous T-cell lymphomas. In this study, we investigate the effect of a recombinant, antibacterial protein, endolysin (XZ.700), on S. aureus skin colonization and malignant T-cell activation. We show that endolysin strongly inhibits the proliferation of S. aureus isolated from cutaneous T-cell lymphoma skin and significantly decreases S. aureus bacterial cell counts in a dose-dependent manner. Likewise, ex vivo colonization of both healthy and lesional skin by S. aureus is profoundly inhibited by endolysin. Moreover, endolysin inhibits the patient-derived S. aureus induction of IFNγ and the IFNγ-inducible chemokine CXCL10 in healthy skin. Whereas patient-derived S. aureus stimulates activation and proliferation of malignant T cells in vitro through an indirect mechanism involving nonmalignant T cells, endolysin strongly inhibits the effects of S. aureus on activation (reduced CD25 and signal transducer and activator of transcription 5 phosphorylation) and proliferation (reduced Ki-67) of malignant T cells and cell lines in the presence of nonmalignant T cells. Taken together, we provide evidence that endolysin XZ.700 inhibits skin colonization, chemokine expression, and proliferation of pathogenic S. aureus and blocks their potential tumor-promoting effects on malignant T cells.

Retrospective analysis of sepsis in cutaneous T-cell lymphoma reveals significantly greater risk in Black patients

BACKGROUND

Sepsis is a leading cause of morbidity, mortality, and resource utilization among patients with cutaneous T-cell lymphoma (CTCL).

OBJECTIVE

To characterize the demographic, clinical, and microbial attributes distinguishing patients with CTCL sepsis from other patients with non-Hodgkin lymphoma (NHL) sepsis and patients with CTCL in general.

METHODS

Two-part retrospective cohort study at an academic medical center from 2001-2019 involving patients with CTCL (n = 97) and non-CTCL NHL (n = 88) admitted with sepsis, and a same-institution CTCL patient database (n = 1094). Overall survival was estimated by Kaplan-Meier analyses.

RESULTS

Patients with CTCL sepsis were more likely to be older, Black, experience more sepsis episodes, die or be readmitted within 30 days of an inpatient sepsis episode, and develop Gram-positive bacteremia than patients with non-CTCL NHL sepsis. Staphylococcus aureus and Escherichia coli were the most frequently speciated organisms in CTCL (26%) and non-CTCL NHL (14%), respectively. No between-group differences were identified regarding sex, presence of central line, chemotherapy use, or disease stage. Compared with general patients with CTCL, patients with sepsis were Black and exhibited advanced-stage disease, higher body surface area involvement, and higher lactate dehydrogenase levels.

LIMITATIONS

Single institution, retrospective nature may limit generalizability.

CONCLUSION

Awareness of CTCL-specific risk factors is crucial for guiding sepsis prevention and improving patient outcomes.

Malignant T cells induce skin barrier defects through cytokine-mediated JAK/STAT signaling in cutaneous T-cell lymphoma

Cutaneous T-cell lymphoma (CTCL) is a devastating lymphoid malignancy characterized by the accumulation of malignant T cells in the dermis and epidermis. Skin lesions cause serious symptoms that hamper quality of life and are entry sites for bacterial infection, a major cause of morbidity and mortality in advanced diseases. The mechanism driving the pathological processes that compromise the skin barrier remains unknown. Here, we report increased transepidermal water loss and compromised expression of the skin barrier proteins filaggrin and filaggrin-2 in areas adjacent to TOX-positive T cells in CTCL skin lesions. Malignant T cells secrete mediators (including cytokines such as interleukin 13 [IL-13], IL-22, and oncostatin M) that activate STAT3 signaling and downregulate filaggrin and filaggrin-2 expression in human keratinocytes and reconstructed human epithelium. Consequently, the repression of filaggrins can be counteracted by a cocktail of antibodies targeting these cytokines/receptors, small interfering RNA-mediated knockdown of JAK1/STAT3, and JAK1 inhibitors. Notably, we show that treatment with a clinically approved JAK inhibitor, tofacitinib, increases filaggrin expression in lesional skin from patients with mycosis fungoides. Taken together, these findings indicate that malignant T cells secrete cytokines that induce skin barrier defects via a JAK1/STAT3-dependent mechanism. As clinical grade JAK inhibitors largely abrogate the negative effect of malignant T cells on skin barrier proteins, our findings suggest that such inhibitors provide novel treatment options for patients with CTCL with advanced disease and a compromised skin barrier.

Micellar Curcumin Substantially Increases the Antineoplastic Activity of the Alkylphosphocholine Erufosine against TWIST1 Positive Cutaneous T Cell Lymphoma Cell Lines

Cutaneous T-cell lymphoma (CTCL) is a rare form of cancer with local as well as systemic manifestations. Concomitant bacterial infections increase morbidity and mortality rates due to impaired skin barrier and immune deficiency. In the current study, we demonstrated that the in vitro anti-lymphoma potential of erufosine is diminished by TWIST1 expression and micellar curcumin substantially increases its antineoplastic activity. Pharmacokinetic analysis showed that the micellar curcumin (MCRM) used in our study was characterized by low zeta potential, slow release of curcumin, and fast cell membrane penetration. The combination ratio 1:4 [erufosine:MCRM] achieved strong synergism by inhibiting cell proliferation and clonogenicity. The combined antiproliferative effects were calculated using the symbolic mathematical software MAPLE 15. The synergistic combination strongly decreased the expression of TWIST1 and protein kinase B/Akt as proven by western blotting. Significant reductions in NF-κB activation, induction of apoptosis, and altered glutathione levels were demonstrated by corresponding assays. In addition, the synergistic combination enhanced the anti-staphylococcal activity and prevented biofilm formation, as shown by crystal violet staining. Taken together, the above results show that the development of nanotechnological treatment modalities for CTCL, based on rational drug combinations exhibiting parallel antineoplastic and antibacterial effects, may prove efficacious.

Narrowband ultraviolet B response in cutaneous T-cell lymphoma is characterized by increased bacterial diversity and reduced Staphylococcus aureus and Staphylococcus lugdunensis

Skin microbiota have been linked to disease activity in cutaneous T-cell lymphoma (CTCL). As the skin microbiome has been shown to change after exposure to narrowband ultraviolet B (nbUVB) phototherapy, a common treatment modality used for CTCL, we performed a longitudinal analysis of the skin microbiome in CTCL patients treated with nbUVB. 16S V4 rRNA gene amplicon sequencing for genus-level taxonomic resolution, tuf2 amplicon next generation sequencing for staphylococcal speciation, and bioinformatics were performed on DNA extracted from skin swabs taken from lesional and non-lesional skin of 25 CTCL patients receiving nbUVB and 15 CTCL patients not receiving nbUVB from the same geographical region. Disease responsiveness to nbUVB was determined using the modified Severity Weighted Assessment Tool: 14 (56%) patients responded to nbUVB while 11 (44%) patients had progressive disease. Microbial α-diversity increased in nbUVB-responders after phototherapy. The relative abundance of Staphylococcus, Corynebacterium, Acinetobacter, Streptococcus, and Anaerococcus differentiated nbUVB responders and non-responders after treatment (q<0.05). Microbial signatures of nbUVB-treated patients demonstrated significant post-exposure depletion of S. aureus (q=0.024) and S. lugdunensis (q=0.004) relative abundances. Before nbUVB, responder lesional skin harboured higher levels of S. capitis (q=0.028) and S. warneri (q=0.026) than non-responder lesional skin. S. capitis relative abundance increased in the lesional skin of responders (q=0.05) after phototherapy; a similar upward trend was observed in non-responders (q=0.09). Post-treatment skin of responders exhibited significantly reduced S. aureus (q=0.008) and significantly increased S. hominis (q=0.006), S. pettenkoferi (q=0.021), and S. warneri (q=0.029) relative abundances compared to that of no-nbUVB patients. Staphylococcus species abundance was more similar between non-responders and no-nbUVB patients than between responders and no-nbUVB patients. In sum, the skin microbiome of CTCL patients who respond to nbUVB is different from that of non-responders and untreated patients, and is characterized by shifts in S. aureus and S. lugdunensis. Non-responsiveness to phototherapy may reflect more aggressive disease at baseline.

Nasal Dysbiosis in Cutaneous T-Cell Lymphoma Is Characterized by Shifts in Relative Abundances of Non-Staphylococcus Bacteria

The nasal microbiome of patients with cutaneous T-cell lymphoma (CTCL) remains unexplored despite growing evidence connecting nasal bacteria to skin health and disease. Nasal swabs from 45 patients with CTCL (40 with mycosis fungoides, 5 with Sézary syndrome) and 20 healthy controls from the same geographical region (Chicago Metropolitan Area, Chicago, IL) were analyzed using sequencing of 16S ribosomal RNA and tuf2 gene amplicons. Nasal α-diversity did not differ between mycosis fungoides/Sézary syndrome and healthy controls (Shannon index, genus level, P = 0.201), but distinct microbial communities were identified at the class (R2 = 0.104, P = 0.023) and order (R2 = 0.0904, P = 0.038) levels. Increased relative abundance of the genera Catenococcus, Vibrio, Roseomonas, Acinetobacter, and unclassified Clostridiales was associated with increased skin disease burden (P < 0.005, q < 0.05). Performed to accurately resolve nasal Staphylococcus at the species level, tuf2 gene amplicon sequencing revealed no significant differences between mycosis fungoides/Sézary syndrome and healthy controls. Although S. aureus has been shown to worsen CTCL through its toxins, no increase in the relative abundance of this taxon was observed in nasal samples. Despite the lack of differences in Staphylococcus, the CTCL nasal microbiome was characterized by shifts in numerous other bacterial taxa. These data add to our understanding of the greater CTCL microbiome and provide context for comprehending nasal-skin and host‒tumor‒microbial relationships.

The Skin Microbiome in Cutaneous T-Cell Lymphomas (CTCL)—A Narrative Review

In recent years, numerous studies have shown a significant role of the skin microbiome in the development and exacerbation of skin diseases. Cutaneous T-cell lymphomas (CTCL) are a group of malignancies primary involving skin, with unclear pathogenesis and etiology. As external triggers appear to contribute to chronic skin inflammation and the malignant transformation of T-cells, some microorganisms or dysbiosis may be involved in these processes. Recently, studies analyzing the skin microbiome composition and diversity have been willingly conducted in CTCL patients. In this review, we summarize currently available data on the skin microbiome in CTLC. We refer to a healthy skin microbiome and the contribution of microorganisms in the pathogenesis and progression of other skin diseases, focusing on atopic dermatitis and its similarities to CTCL. Moreover, we present information about the possible role of identified microorganisms in CTCL development and progression. Additionally, we summarize information about the involvement of Staphylococcus aureus in CTCL pathogenesis. This article also presents therapeutic options used in CTCL and discusses how they may influence the microbiome.

Gut dysbiosis in cutaneous T-cell lymphoma is characterized by shifts in relative abundances of specific bacterial taxa and decreased diversity in more advanced disease

BACKGROUND

Cutaneous T-cell lymphoma (CTCL) patients often suffer from recurrent skin infections and profound immune dysregulation in advanced disease. The gut microbiome has been recognized to influence cancers and cutaneous conditions; however, it has not yet been studied in CTCL.

OBJECTIVES

To investigate the gut microbiome in patients with CTCL and in healthy controls.

METHODS

Case-control study conducted between January 2019 and November 2020 at Northwestern's busy multidisciplinary CTCL clinic (Chicago, Illinois, USA) utilizing 16S ribosomal RNA gene amplicon sequencing and bioinformatics analyses to characterize the microbiota present in fecal samples of CTCL patients (n=38) and age-matched healthy controls (n=13) from the same geographical region.

RESULTS

Gut microbial α-diversity trended lower in patients with CTCL and was significantly lower in patients with advanced CTCL relative to controls (p=0.015). No differences in β-diversity were identified. Specific taxa were significantly reduced in patient samples; significance was determined using adjusted p-values (q-values) that accounted for a false discovery rate threshold of 0.05. Significantly reduced taxa in patient samples included the phylum Actinobacteria (q=0.0002), classes Coriobacteriia (q=0.002) and Actinobacteria (q=0.03), order Coriobacteriales (q=0.003), and genus Anaerotruncus (q=0.01). The families of Eggerthellaceae (q=0.0007) and Lactobacillaceae (q=0.02) were significantly reduced in patients with high skin disease burden.

CONCLUSIONS

Gut dysbiosis can be seen in patients with CTCL compared to healthy controls and is pronounced in more advanced CTCL. The taxonomic shifts associated with CTCL are similar to those previously reported in atopic dermatitis and opposite those of psoriasis, suggesting microbial parallels to the immune profile and skin barrier differences between these conditions. These findings may suggest new microbial disease biomarkers and reveal a new angle for intervention.

Malignant T Cell Activation by a Bacillus Species Isolated from Cutaneous T-Cell Lymphoma Lesions

Cutaneous T-cell lymphoma (CTCL) is a life-debilitating malignancy of lymphocytes homing to the skin. Although CTCL is thought to arise from a combination of genetic, epigenetic, and environmental factors, specific triggers are unclear. The skin is colonized by a unique microbiota and is heavily influenced by its interactions. We hypothesized that adaptive immune responses to skin commensals lead to clonal T-cell proliferation and transformation in the appropriate genetic background. We therefore collected lesional and nonlesional skin microbiota from patients with CTCL to study T cell interactions using skin T cell explants and peripheral, skin-homing CD4+ T cells. By various methods, we identified Bacillus safensis in CTCL lesions, a rare human commensal in healthy skin, and showed that it can induce malignant T cell activation and cytokine secretion. Taken together, our data suggest microbial triggers in the skin microbiota of patients with CTCL as potential instigators of tumorigenesis.

Understanding Cell Lines, Patient-Derived Xenograft and Genetically Engineered Mouse Models Used to Study Cutaneous T-Cell Lymphoma

Cutaneous T cell lymphoma (CTCL) is a spectrum of lymphoproliferative disorders caused by the infiltration of malignant T cells into the skin. The most common variants of CTCL include mycosis fungoides (MF), Sézary syndrome (SS) and CD30⁺ Lymphoproliferative disorders (CD30⁺ LPDs). CD30⁺ LPDs include primary cutaneous anaplastic large cell lymphoma (pcALCL), lymphomatoid papulosis (LyP) and borderline CD30⁺ LPD. The frequency of MF, SS and CD30⁺ LPDs is ~40–50%, <5% and ~10–25%, respectively. Despite recent advances, CTCL remains challenging to diagnose. The mechanism of CTCL carcinogenesis still remains to be fully elucidated. Hence, experiments in patient-derived cell lines and xenografts/genetically engineered mouse models (GEMMs) are critical to advance our understanding of disease pathogenesis. To enable this, understanding the intricacies and limitations of each individual model system is highly important. Presently, 11 immortalized patient-derived cell lines and different xenograft/GEMMs are being used to study the pathogenesis of CTCL and evaluate the therapeutic efficacy of various treatment modalities prior to clinical trials. Gene expression studies, and the karyotyping analyses of cell lines demonstrated that the molecular profile of SeAx, Sez4, SZ4, H9 and Hut78 is consistent with SS origin; MyLa and HH resemble the molecular profile of advanced MF, while Mac2A and PB2B represent CD30⁺ LPDs. Molecular analysis of the other two frequently used Human T-Cell Lymphotropic Virus-1 (HTLV-1)⁺ cell lines, MJ and Hut102, were found to have characteristics of Adult T-cell Leukemia/Lymphoma (ATLL). Studies in mouse models demonstrated that xenograft tumors could be grown using MyLa, HH, H9, Hut78, PB2B and SZ4 cells in NSG (NOD Scid gamma mouse) mice, while several additional experimental GEMMs were established to study the pathogenesis, effect of drugs and inflammatory cytokines in CTCL. The current review summarizes cell lines and xenograft/GEMMs used to study and understand the etiology and heterogeneity of CTCL.

Transcriptional Heterogeneity and the Microbiome of Cutaneous T-Cell Lymphoma

Cutaneous T-Cell Lymphomas (CTCL) presents with substantial clinical variability and transcriptional heterogeneity. In the recent years, several studies paved the way to elucidate aetiology and pathogenesis of CTCL using sequencing methods. Several T-cell subtypes were suggested as the source of disease thereby explaining clinical and transcriptional heterogeneity of CTCL entities. Several differentially expressed pathways could explain disease progression. However, exogenous triggers in the skin microenvironment also seem to affect CTCL status. Especially Staphylococcus aureus was shown to contribute to disease progression. Only little is known about the complex microbiome patterns involved in CTCL and how microbial shifts might impact this malignancy. Nevertheless, first hints indicate that the microbiome might at least in part explain transcriptional heterogeneity and that microbial approaches could serve in diagnosis and prognosis. Shaping the microbiome could be a treatment option to maintain stable disease. Here, we review current knowledge of transcriptional heterogeneity of and microbial influences on CTCL. We discuss potential benefits of microbial applications and microbial directed therapies to aid patients with CTCL burden.

Recurrent Bacterial Infections in Cutaneous T-cell Lymphoma

Cutaneous T-cell lymphoma (CTCL) is a dermatologically manifesting immune cell disorder. We present a case of a 76-year-old female with a past medical history of CTCL, presenting with cellulitis of the left foot. After diagnosis of CTCL, the patient was admitted multiple times for treatment of cutaneous and soft-tissue infections with methicillin-resistant Staphylococcus aureus. Her recurrent infection with S. aureus had led to treatment for sepsis and a below-knee amputation on the right during prior hospitalizations. On this admission, the patient was treated with intravenous vancomycin and cefepime as in-patient and oral linezolid as out-patient. Recent articles show that patients with CTCL have an increased tendency to harbor S. aureus, which leads to recurrent infections. Additionally, evidence suggests that S. aureus toxins aid the progression of CTCL by helping the cancer to escape immune regulation. Our patient demonstrates this unique relationship between CTCL and S. aureus, and moreover, we make a case that S. aureus infection in CTCL, as compared to that in other dermatitis, should be better managed to not exacerbate the disease. 

In Vitro Antineoplastic and Antiviral Activity and In Vivo Toxicity of Geum urbanum L. Extracts

This study evaluated the in vitro antineoplastic and antiviral potential and in vivo toxicity of twelve extracts with different polarity obtained from the herbaceous perennial plant Geum urbanum L. (Rosaceae). In vitro cytotoxicity was determined by ISO 10993-5/2009 on bladder cancer, (T-24 and BC-3C), liver carcinoma (HEP-G2) and normal embryonic kidney (HEK-293) cell lines. The antineoplastic activity was elucidated through assays of cell clonogenicity, apoptosis induction, nuclear factor kappa B p65 (NFκB p65) activation and total glutathione levels. Neutral red uptake study was applied for antiviral activity. The most promising G. urbanum extract was analyzed by UHPLC–HRMS. The acute in vivo toxicity analysis was carried out following OEDC 423. The ethyl acetate extract of aerial parts (EtOAc-AP) exhibited the strongest antineoplastic activity on bladder cancer cell lines (IC₅₀ = 21.33–25.28 µg/mL) by inducing apoptosis and inhibiting NFκB p65 and cell clonogenicity. EtOAc and n-butanol extracts showed moderate antiviral activity against human adenovirus type 5 and human simplex virus type I. Seventy four secondary metabolites (gallic and ellagic acid derivatives, phenolic acids, flavonoids, etc.) were identified in EtOAc-AP by UHPLC–HRMS. This extract induced no signs of acute toxicity in liver and kidney specimens of H-albino mice in doses up to 210 mg/kg. In conclusion, our study contributes substantially to the detailed pharmacological characterization of G. urbanum, thus helping the development of health-promoting phytopreparations.

Pathogenesis of cutaneous T cell lymphoma: Involvement of Staphylococcus aureus

Mycosis fungoides (MF) and Sézary syndrome (SS) are representative cutaneous lymphomas. In their early stage, a small number of tumor cells and a large number of non-malignant cells form a Th1-dominant tumor microenvironment. Increase in malignant T cells is accompanied by a decrease in CD8-positive T cells, with a shift toward a Th2-dominant milieu in advanced-stage lesions. The etiologies of MF/SS are diverse, and the underlying pathogenetic mechanisms are yet to be elucidated. Advanced MF/SS is known to be highly sensitive to Staphylococcus aureus, and the majority of deaths are caused by severe infections. The susceptibility to infection is associated with barrier dysfunction and immunosuppression, which are the main symptoms of MF. In recent years, skin-colonizing S. aureus has been identified to not only cause severe infections but also play an important role in the pathogenesis of MF/SS. Staphylococcal superantigens activate the proliferation of tumor cells and induce CD25 upregulation, FOXP3 expression, IL-17 expression, and miR-155 expression. Alpha-toxin eliminates non-neoplastic CD4-positive cells and CD8-positive cells and plays a major role in tumor cell selection. Lipoprotein may also be associated with the induction of Th2-dominant milieu. Antibiotic therapy for S. aureus eradication has been reported to cause considerable clinical improvement in the majority of individuals with advanced cutaneous T-cell lymphoma. Therefore, S. aureus may be a novel target for the treatment of advanced-stage MF/SS in the future.

Mycosis fungoides and Sézary syndrome

Mycosis fungoides (MF) and Sézary syndrome (SS) are primary cutaneous T-cell lymphomas (CTCL) with not yet fully understood etiology and pathogenesis. Conceptually, MF and SS are classified as distinct entities arising from different T helper cell subsets. MF is the most common CTCL entity, while SS is very rare. MF presents clinically with patch, plaque and/or tumor stages, but can also evolve as erythroderma, which in turn is pathognomonic for SS. SS is characterized by a detectable tumor-cell burden (Sézary cells) in the peripheral blood consistent with advanced-stage disease and a poor prognosis. In early-stage disease of MF, which is the predominant form, the prognosis is generally favorable. However, in up to 30 % of patients, there is progression of skin lesions, which can ultimately lead to visceral involvement. The histological manifestation of MF can be subtle in early-stage disease and therefore a careful clinicopathological correlation is paramount. The treatment of MF/SS is dependent on the disease stage. Therapeutic options include both skin-directed and systemic regimens. Apart from allogeneic stem cell transplantation (alloSCT), there is as yet no curative therapy for MF/SS. Accordingly, the treatment approach is symptom oriented and aims to reduce the tumor burden and improve health-related quality of life. However, the therapeutic landscape for CTCL is constantly being expanded by the discovery of novel therapeutic targets.

Aggressive T-cell lymphomas: 2021 Updates on diagnosis, risk stratification and management

INTRODUCTION

Aggressive T-cell lymphomas continue to have a poor prognosis. There are over 27 different subtypes of peripheral T-cell lymphoma (PTCL), and we are now beginning to understand the differences between the various subtypes beyond histologic variations.

MOLECULAR PATHOGENESIS OF VARIOUS SUBTYPES OF PTCL

Gene expression profiling (GEP) can help in diagnosis and prognostication of various subtypes including PTCL-nos and anaplastic large cell lymphoma (ALCL). In addition, mutational analysis is now being incorporated in clinical trials of novel agents to evaluate various biomarkers of response to allow better therapeutic choices for patients.

TARGETED THERAPIES

There are many targeted agents currently in various stages of clinical trials for PTCL that take advantage of the differential expression of specific proteins or receptors in PTCL tumors. This includes the CD30 directed antibody drug conjugate brentuximab vedotin. Other notable targets are CD25, CCR4, inhibition of PI3kinase - m TOR and JAK/STAT pathways. The ALK inhibitors are promising for ALK expressing tumors.

IMMUNOTHERAPIES

Allogeneic stem cell transplant continues to be the curative therapy for most aggressive subtypes of PTCL. The use of checkpoint inhibitors in the treatment of PTCL is still controversial. The most promising results have been seen in cases of extranodal natural killer cell/T-cell (ENK/T) lymphomas and cutaneous T-cell lymphomas (CTCL). Bispecific antibody based treatments as well as CAR-T cell based therapies are in clinical trials.

Staphylococcus aureus Induces Signal Transducer and Activator of Transcription 5‒Dependent miR-155 Expression in Cutaneous T-Cell Lymphoma

Staphylococcal enterotoxins are believed to fuel disease activity in cutaneous T-cell lymphoma. Recent data support this by showing that antibiotics inhibit malignant T cells in skin lesions in mycosis fungoides and Sézary syndrome, the most common forms of cutaneous T-cell lymphoma. Yet, it remains incompletely characterized how staphylococcal enterotoxins fuel disease activity. In this study, we show that staphylococcal enterotoxins induce the expression of the oncogenic microRNA miR-155 in primary malignant T cells. Thus, staphylococcal enterotoxins and Staphyloccocus aureus isolates from lesional skin of patients induce miR-155 expression at least partly through the IL-2Rg‒Jak‒signal transducer and activator of transcription 5 pathway, and the effect is augmented by the presence of nonmalignant T cells. Importantly, mycosis fungoides lesions harbor S. aureus, express Y-phosphorylated signal transducer and activator of transcription 5, and display enhanced miR-155 expression, when compared with nonlesional and healthy skin. Preliminary data show that aggressive antibiotic therapy is associated with decreased Y-phosphorylated signal transducer and activator of transcription 5 and miR-155 expression in lesional skin in two patients with Sézary syndrome. In conclusion, we show that S. aureus and its enterotoxins induce enhanced expression of oncogenic miR-155, providing mechanistic insight into the role of S. aureus in cutaneous T-cell lymphoma. Our findings support that environmental stimuli such as bacteria can fuel disease progression in cutaneous T-cell lymphoma.

The immunopathogenesis and immunotherapy of cutaneous T cell lymphoma: Pathways and targets for immune restoration and tumor eradication

Cutaneous T cell lymphomas (CTCLs) are malignancies of skin-trafficking T cells. Patients with advanced CTCL manifest immune dysfunction that predisposes to infection and suppresses the antitumor immune response. Therapies that stimulate immunity have produced superior progression-free survival compared with conventional chemotherapy, reinforcing the importance of addressing the immune deficient state in the care of patients with CTCL. Recent research has better defined the pathogenesis of these immune deficits, explaining the mechanisms of disease progression and revealing potential therapeutic targets. The features of the malignant cell in mycosis fungoides and Sézary syndrome are now significantly better understood, including the T helper 2 cell phenotype, regulatory T cell cytokine production, immune checkpoint molecule expression, chemokine receptors, and interactions with the microenvironment. The updated model of CTCL immunopathogenesis provides understanding into clinical progression and therapeutic response.

Antineoplastic effect of a novel nanosized curcumin on cutaneous T cell lymphoma

Cutaneous T cell lymphomas (CTCLs) are a group of heterogeneous, life-threatening, extra-nodal and lymphoproliferative T cell neoplasms. Since chronic inflammation serves a key role in CTCL progression, curcumin, a natural pigment with proven anti-inflammatory and antineoplastic properties, as well as minimal toxicity, may be used as a therapeutic agent. In the present study, two formulations of curcumin (standard ethanolic and a Pluronic^®P-123/F-127 micellar solution) were compared regarding their cytotoxic efficacy and speed of internalization in three CTCL cell lines, namely HuT-78, HH and MJ. In addition, the modulating effect of curcumin on selected proteins involved in the proliferation and progression of the disease was determined. The results indicated the superiority of the Pluronic^®P-123/F-127 micellar curcumin over the standard ethanol solution in terms of cellular internalization efficiency as determined by spectrophotometric analysis. Notably, the presence of commonly used media components, such as phenol red, may interfere when interpreting the cytotoxicity of curcumin, due to their overlapping absorbance peaks. Therefore, it was concluded that phenol red-free media are superior over media with phenol red in order to correctly measure the cytotoxic efficacy and cell penetration of curcumin. Depending on the cell line, the IC₅₀ values of micellar curcumin varied from 29.76 to 1.24 µΜ, with HH cells demonstrating the highest sensitivity. This cell line had the lowest expression levels of the Wilms' tumor-1 transcription factor. Performing western blot analyses of treated and untreated CTCL cells, selective signal transduction changes were recorded for the first time, thus making curcumin nano-formulation an attractive and prospective option with therapeutic relevance for CTCL as a rare orphan disease.

Cellular Interactions and Inflammation in the Pathogenesis of Cutaneous T-Cell Lymphoma

Cutaneous T-cell lymphoma (CTCL) comprises a group of lymphoproliferative diseases characterized by the accumulation of malignant T cells in chronically inflamed skin lesions. In early stages, the disease presents as skin patches or plaques covering a limited area of the skin and normally follows an indolent course. However, in a subset of patients the cutaneous lesions develop into tumors and the malignant T cells may spread to the lymphatic system, blood and internal organs with fatal consequences. Despite intensive research, the mechanisms driving disease progression remain incompletely understood. While most studies have focused on cancer cell-intrinsic oncogenesis, such as genetic and epigenetic events driving malignant transformation and disease progression, an increasing body of evidence shows that the interplay between malignant T cells and non-malignant cells plays a crucial role. Here, we outline some of the emerging mechanisms by which tumor, stromal and epidermal interactions may contribute to the progression of CTCL with particular emphasis on the crosstalk between fibroblasts, keratinocytes and malignant T cells.

The Thioredoxin-Interacting Protein TXNIP Is a Putative Tumour Suppressor in Cutaneous T-Cell Lymphoma

BACKGROUND

The thioredoxin-interacting protein (TXNIP) is involved in cellular metabolism and cell proliferation, and recently, deficient expression of TXNIP has been associated with progression and poor outcome for cancer patients.

OBJECTIVES

To assess TXNIP expression and function in malignant T cells from cutaneous T-cell lymphoma (CTCL).

METHODS

CTCL-derived malignant (MyLa2059, PB2B) and non-malignant (MyLa1850) cell lines were analysed by Western blotting and qPCR for TXNIP expression. Subsequently, the malignant CTCL cell lines were treated with GSK126 - an inhibitor of enhancer of zeste homolog 2 (EZH2) methyltransferase activity or assessed by bisulphite sequencing for TXNIP promoter methylation. Methylation was also assessed with the demethylating agent 5-azacytidine (5AZA). Finally, TXNIP was overexpressed in the malignant PB2B cell line via plasmid transduction, and the effect of TXNIP was further analysed by flow cytometry.

RESULTS

We report on low expression of TXNIP protein in all cell lines representing different subtypes and stages of CTCL when compared to non-malignant T cells. Epigenetic silencing and other mechanisms were involved in the repression of TXNIP whereas forced expression of TXNIP strongly inhibited proliferation of malignant T cells.

CONCLUSIONS

Epigenetic silencing and other as yet unknown mechanisms repress TXNIP expression in malignant T cells. As forced expression of TXNIP inhibits malignant proliferation, we propose that TXNIP is a putative tumour suppressor in CTCL.

Staphylococcus aureus enterotoxins induce FOXP3 in neoplastic T cells in Sézary syndrome

Sézary syndrome (SS) is a heterogeneous leukemic subtype of cutaneous T-cell lymphoma (CTCL) with generalized erythroderma, lymphadenopathy, and a poor prognosis. Advanced disease is invariably associated with severe immune dysregulation and the majority of patients die from infectious complications caused by microorganisms such as, Staphylococcus aureus, rather than from the lymphoma per se. Here, we examined if staphylococcal enterotoxins (SE) may shape the phenotype of malignant SS cells, including expression of the regulatory T-cell-associated marker FOXP3. Our studies with primary and cultured malignant cells show that SE induce expression of FOXP3 in malignant cells when exposed to nonmalignant cells. Mutations in the MHC class II binding domain of SE-A (SEA) largely block the effect indicating that the response relies at least in part on the MHC class II-mediated antigen presentation. Transwell experiments show that the effect is induced by soluble factors, partly blocked by anti-IL-2 antibody, and depends on STAT5 activation in malignant cells. Collectively, these findings show that SE stimulate nonmalignant cells to induce FOXP3 expression in malignant cells. Thus, differences in exposure to environmental factors, such as bacterial toxins may explain the heterogeneous FOXP3 expression in malignant cells in SS.

Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen in erythrodermic cutaneous T-cell lymphoma (CTCL) patients

Erythroderma can occur in cutaneous T-cell lymphoma (CTCL). Staphylococcus aureus (S. aureus) prevalence is increased in CTCL patients and contributes to CTCL disease flares. Our primary aim was to describe S. aureus infections, including resistance patterns and the antibiotic treatment regimens used, in erythrodermic CTCL patients. This was a retrospective chart review of erythrodermic CTCL patients who had S. aureus infection or colonization and were treated at the UT MD Anderson Cancer Center's Melanoma Skin Center between 2012 and 2016. Twenty-six erythrodermic CTCL patients had 50 documented S. aureus colonization or infection events. Patients had an improvement in body surface area (BSA) or modified Severity Weighted Assessment Tool (mSWAT) in 53% events treated for S. aureus. Seventeen of the 50 (34%) events were due to methicillin-resistant S. aureus (MRSA). One-third (33%) of MRSA events were initially treated with dicloxacillin. The MRSA isolates were sensitive to trimethoprim-sulfamethoxazole (92%) and doxycycline (88%). Patients treated in the outpatient setting (OR 0.073; 95% CI 0.008-0.627; p = 0.017) and patients with a previous history of topical anti-S. aureus decolonization treatments before S. aureus event as stand-alone (OR 0.125; 95% CI 0.018-0.887; p = 0.038) or in combination treatment with systemic antibiotics (OR 0.094; 95% CI 0.009-0.944; p = 0.045) were less likely to see improvement in BSA or mSWAT from S. aureus treatment. Treatment of S. aureus improved CTCL skin score in a high number of erythrodermic patients. The MRSA prevalence was high in erythrodermic CTCL patients. Clinicians should consider using empiric MRSA antibiotic coverage for these patients.

Expression Profiles of Genes Encoding Cornified Envelope Proteins in Atopic Dermatitis and Cutaneous T-Cell Lymphomas

The skin barrier defect in cutaneous T-cell lymphomas (CTCL) was recently confirmed to be similar to the one observed in atopic dermatitis (AD). We have examined the expression level of cornified envelope (CE) proteins in CTCL, AD and healthy skin, to search for the differences and their relation to the courses of both diseases. The levels of FLG, FLG2, RPTN, HRNR, SPRR1A, SPRR1B, SPRR3 and LELP-1 mRNA were determined by qRT-PCR, while protein levels were examined using the ELISA method in skin samples. We have found that mRNA levels of FLG, FLG2, LOR, CRNN and SPRR3v1 were decreased (p ≤ 0.04), whereas mRNA levels of RPTN, HRNR and SPRR1Av1 were increased in lesional and nonlesional AD skin compared to the healthy control group (p ≤ 0.04). The levels of FLG, FLG2, CRNN, SPRR3v1 mRNA increased (p ≤ 0.02) and RPTN, HRNR and SPRR1Av1 mRNA decreased (p ≤ 0.005) in CTCL skin compared to the lesional AD skin. There was a strong correlation between the stage of CTCL and increased SPRR1Av1 gene expression at both mRNA (R = 0.89; p ≤ 0.05) and protein levels (R = 0.94; p ≤ 0.05). FLG, FLG2, RPTN, HRNR and SPRR1A seem to play a key role in skin barrier dysfunction in CTCL and could be considered a biomarker for differential diagnosis of AD and CTCL. SPRR1Av1 transcript levels seem to be a possible marker of CTCL stage, however, further studies on a larger study group are needed to confirm our findings.

Evidence linking atopy and staphylococcal superantigens to the pathogenesis of lymphomatoid papulosis, a recurrent CD30+ cutaneous lymphoproliferative disorder

Background

Primary cutaneous CD30+ lymphoproliferative disorders (CD30CLPD) are the second most common type of cutaneous T cell lymphoma (CTCL) and include lymphomatoid papulosis (LyP) and primary cutaneous anaplastic large cell lymphoma (pcALCL). Case reports and small patient series suggest an association of CD30CLPD with atopic disorders. However, the prevalence of atopy in patients with CD30CLPD in retrospective studies depends on patients’ recall which is not always reliable. More objective criteria of atopy include evidence of skin reactivity to allergens (positive prick test) and evidence of allergen-specific IgE in serum. This study was undertaken to test the hypothesis that atopy is prevalent in patients with CD30CLPD using serologic criteria of allergen-specific IgE antibodies to aeroallergens and Staphylococcal aureus enterotoxin superantigens (SSAgs).

Methods

We tested serum samples of CD30CLPD for common IgE-specific airborne allergens with the Phadiatop test, which if positive, is regarded as serologic evidence of atopy in adults. Sera were also tested for IgE antibodies reactive to three Staphylococcal enterotoxins with superantigenic properties (SSAg-IgE). Control sera were obtained from adult subjects evaluated for rhino-sinusitis and a negative Phadiatop test. Patients’ history of an atopic disorder was obtained by retrospective chart review.

Findings

Nearly 50% of patients with the most common LyP types (A and C) had a positive Phadiatop test for allergic sensitization to common airborne allergens, and total serum IgE (IgE-t) was increased compared to non-atopic controls. At the IgE antibody concentration generally used to define serologic atopy (≥ 0.35 kU_A/L), 8/31 (26%) samples of CD30CLPD and 7/28 (25%) samples of LyP were reactive to at least one SSAg-IgE compared to 3/52 (6%) control specimens (P = 0.016 and P = 0.028, respectively). TSST1-IgE was detected in 7 (23%) specimens of CD30CLPD, often together with SEB-IgE; SEA-IgE ≥ 0.35 kU_A/L was not detected. For control specimens, TSST1-IgE exceeded the 0.35 kU_A/L threshold in 3 (6%) specimens.

Conclusions

Patients with LyP types A and C have serologic evidence of atopy against common airborne antigens and SSAgs when compared to control adult subjects who had rhino-sinusitis and a negative Phadiatop test for aero-IgEs. Serologic evidence of atopy exceeded that determined by LyP patients’ personal history. The findings support our hypothesis that an atopic diathesis may contribute to the pathogenesis of the most common types of LyP (A and C).

Prevalence of atopy and staphylococcal superantigen-specific immunoglobulin E (IgE) antibodies and total serum IgE in primary cutaneous T- and B-cell lymphoma

The prevalence of atopy was investigated in 20 patients with Sézary syndrome (SS), 20 patients with plaque phase mycosis fungoides (MF), 9 patients with primary cutaneous marginal zone lymphoma (pcMZL) and 8 patients with primary cutaneous follicle center lymphoma (pcFCL) with the Phadiatop multi-allergen test. The relationship among serologic atopy, IgE reactivity against Staphyloccocal enterotoxin superantigens, and serum total IgE (IgE-t) levels and their prognostic implications in SS was investigated. Phadiatop test was positive in 45%, 15%, 33% and 0% of samples of SS, MF, pcMZL and pcFCL, respectively. IgE-t levels were also increased in SS, pcMZL and marginally MF. No correlation was found with patients' history of atopic disorders. Staphylococcal superantigen-specific IgE ≥ 0.35 kUa/L, most often against toxic shock syndrome toxin-1, was detected in 40% of Sézary samples followed by MF (20%). In the absence of serologic atopy (negative Phadiatop test), IgE-t levels for patients with SS and MF were not significantly higher than controls whereas the levels for pcMZL remained high. Furthermore, even with a negative Phadiatop test, IgE-t values were higher in sera of patients with SSAg-IgE ≥ 0.35 kUa/L vis-à-vis < 0.35 kUa/L across all diagnostic categories including controls albeit the difference was statistically significant only for SS. The presence of specific IgE antibodies ≥ 0.35 kUa/L, IgE-t > 122 kU/L or eosinophils > 500/µL had no impact on survival of patients with SS. These results indicate that a pathogenic link may exist between an atopic diathesis and development of SS and possibly pcMZL.

Analysis of the Effect of Gentian Violet on Apoptosis and Proliferation in Cutaneous T-Cell Lymphoma in an In Vitro Study

Importance

Triggering the extrinsic apoptotic pathway is an effective way to kill cutaneous T-cell lymphoma (CTCL) cells in vitro and ex vivo.

Objective

To compare small molecules that induce extrinsic apoptosis in CTCL to identify and analyze compounds that induce high levels of tumor cell death and block tumor cell growth.

Design, Setting, and Participants

From November 5, 2014, to January 30, 2018, this study performed high-throughput small molecule screening of 1710 compounds followed by detailed analysis of the ability of gentian violet (GV) to promote apoptosis and inhibit proliferation of CTCL cells.

Exposures

In vitro and ex vivo analyses using enzyme-linked immunosorbent assays, flow cytometry, and immunoblotting.

Main Outcomes and Measures

Apoptosis, cleaved caspases, extrinsic apoptotic death receptors and ligands, cell proliferation, nuclear factor-κB expression, and other factors.

Results

This study used high-throughput screening to detect cleaved caspase 8 induced in CTCL cells by 1710 unique compounds. The nonprescription, topical antimicrobial remedy GV induced more total apoptosis than did nitrogen mustard (mechlorethamine). Furthermore, GV induced 4 to 6 times greater apoptosis in CTCL lines than in normal keratinocytes, suggesting a favorable topical toxicity profile. In addition to increasing caspase 8, GV also upregulated death receptors 4 and 5, tumor necrosis factor (TNF)-related apoptosis-inducing ligand, and Fas ligand but not the Fas receptor, TNF receptor, or TNF-α ligand. These results are consistent with induction of extrinsic apoptosis via the Fas and TNF-related apoptosis-inducing ligand pathways. Increased phosphorylation of phospholipase C-γ1, Ca2+ influx, and reactive oxygen species were also detected, indicating that the mechanism of Fas ligand upregulation involves key elements of the activation-induced cell death pathway. In ex vivo studies, 1-μmol/L GV induced up to 90% CTCL apoptosis in Sézary blood cells. In addition, GV reduced expression of antiapoptotic myeloid cell leukemia 1 and proproliferative nuclear factor-κB components and increased inhibitory κB levels. This finding was associated with cell cycle arrest and reduced CTCL tumor cell proliferation. Furthermore, the CTCL killing associated with GV was augmented when used in combination with methotrexate.

Conclusions and Relevance

This study found that GV attacked tumor viability and growth in CTCL. Although purple at neutral pH, GV can be rendered colorless by altering its pH. These preclinical findings may help to broaden knowledge of the antineoplastic features of GV and provide a rationale for clinical studies of its use as a novel, inexpensive, topical therapy for CTCL that is available worldwide.

Aggressive T-cell lymphomas: 2019 updates on diagnosis, risk stratification, and management

INTRODUCTION

Aggressive T-cell lymphomas continue to have a poor prognosis. There are over 27 different subtypes of peripheral T-cell lymphoma (PTCL) and we are now beginning to understand the differences between the various subtypes beyond histologic variations.

MOLECULAR PATHOGENESIS OF VARIOUS SUBTYPES OF PTCL

Gene expression profiling can help in diagnosis and prognostication of various subtypes including PTCL-nos and anaplastic large cell lymphoma. In addition, mutational analysis is now being incorporated in clinical trials of novel agents to evaluate various biomarkers of response to allow better therapeutic choices for patients.

TARGETED THERAPIES

There are many targeted agents currently in various stages of clinical trials for PTCL that take advantage of the differential expression of specific proteins or receptors in PTCL tumors. The most promising is the CD30 directed antibody drug conjugate brentuximab vedotin. This has recently been approved by the Food and Drug Administration for the upfront treatment of CD30 expressing PTCLs in combination with cyclophosphamide, doxorubicin, and prednisone chemotherapy. Other notable targets are CD25, CCR4 tag, PI3kinase inhibitors, and JAK/STAT inhibitors. Anaplastic lymphoma kinase (ALK) inhibitors are promising for ALK expressing tumors.

IMMUNOTHERAPIES

The use of checkpoint inhibitors in the treatment of PTCL is still controversial. The most promising results have been seen in cases of extranodal natural killer cell/T-cell lymphomas and cutaneous T-cell lymphomas. For all other subtypes, immune checkpoint inhibitors should be used with extreme caution and only in the context of a clinical trial. Allogeneic stem cell transplant continues to be the curative therapy for most aggressive subtypes of PTCL.

Antibiotics inhibit tumor and disease activity in cutaneous T-cell lymphoma

It has been proposed that CD4 T-cell responses to Staphylococcus aureus (SA) can inadvertently enhance neoplastic progression in models of skin cancer and cutaneous T-cell lymphoma (CTCL). In this prospective study, we explored the effect of transient antibiotic treatment on tumor cells and disease activity in 8 patients with advanced-stage CTCL. All patients experienced significant decrease in clinical symptoms in response to aggressive, transient antibiotic treatment. In some patients, clinical improvements lasted for more than 8 months. In 6 of 8 patients, a malignant T-cell clone could be identified in lesional skin, and a significant decrease in the fraction of malignant T cells was observed following antibiotics but an otherwise unchanged treatment regimen. Immunohistochemistry, global messenger RNA expression, and cell-signaling pathway analysis indicated that transient aggressive antibiotic therapy was associated with decreased expression of interleukin-2 high-affinity receptors (CD25), STAT3 signaling, and cell proliferation in lesional skin. In conclusion, this study provides novel evidence suggesting that aggressive antibiotic treatment inhibits malignant T cells in lesional skin. Thus, we provide a novel rationale for treatment of SA in advanced CTCL.

Staphylococcal alpha-toxin tilts the balance between malignant and non-malignant CD4+ T cells in cutaneous T-cell lymphoma

Staphylococcus aureus is implicated in disease progression in cutaneous T-cell lymphoma (CTCL). Here, we demonstrate that malignant T cell lines derived from CTCL patients as well as primary malignant CD4⁺ T cells from Sézary syndrome patients are considerably more resistant to alpha-toxin-induced cell death than their non-malignant counterparts. Thus, in a subset of Sézary syndrome patients the ratio between malignant and non-malignant CD4⁺ T cells increases significantly following exposure to alpha-toxin. Whereas toxin-induced cell death is ADAM10 dependent in healthy CD4⁺ T cells, resistance to alpha-toxin in malignant T cells involves both downregulation of ADAM10 as well as other resistance mechanisms. In conclusion, we provide first evidence that Staphylococcus aureus derived alpha-toxin can tilt the balance between malignant and non-malignant CD4⁺ T cells in CTCL patients. Consequently, alpha-toxin may promote disease progression through positive selection of malignant CD4⁺ T cells, identifying alpha-toxin as a putative drug target in CTCL.

Single-Cell Lymphocyte Heterogeneity in Advanced Cutaneous T-cell Lymphoma Skin Tumors

PURPOSE

The heterogeneity of tumor cells presents a major challenge to cancer diagnosis and therapy. Cutaneous T-cell lymphomas (CTCL) are a group of T lymphocyte malignancies that primarily affect skin. Lack of highly specific markers for malignant lymphocytes prevents early diagnosis, while only limited treatment options are available for patients with advanced stage CTCL. Droplet-based single-cell transcriptome analysis of CTCL skin biopsies opens avenues for dissecting patient-specific T lymphocyte heterogeneity, providing a basis for identifying specific markers for diagnosis and cure of CTCL.

EXPERIMENTAL DESIGN

Single-cell RNA-sequencing was performed by Droplet-based sequencing (10X Genomics), focusing on 14,056 CD3⁺ lymphocytes (448 cells from normal and 13,608 cells from CTCL skin samples) from skin biopsies of 5 patients with advanced-stage CTCL and 4 healthy donors. Protein expression of identified genes was validated in advanced stage CTCL skin tumors by immunohistochemistry and confocal immunofluorescence microscopy.

RESULTS

Our analysis revealed a large inter- and intratumor gene expression heterogeneity in the T lymphocyte subset, as well as a common gene expression signature in highly proliferating lymphocytes that was validated in multiple advanced-stage skin tumors. In addition, we established the immunologic state of reactive lymphocytes and found heterogeneity in effector and exhaustion programs across patient samples.

CONCLUSIONS

Single-cell analysis of CTCL skin tumor samples reveals patient-specific landscapes of malignant and reactive lymphocytes within the local microenvironment of each tumor, giving an unprecedented view of lymphocyte heterogeneity and identifying tumor-specific molecular signatures, with important implications for diagnosis and personalized disease treatment.

Benign T cells drive clinical skin inflammation in cutaneous T cell lymphoma

Psoralen plus UVA (PUVA) is an effective therapy for mycosis fungoides (MF), the skin-limited variant of cutaneous T cell lymphoma (CTCL). In low-burden patients, PUVA reduced or eradicated malignant T cells and induced clonal expansion of CD8+ T cells associated with malignant T cell depletion. High-burden patients appeared to clinically improve but large numbers of malignant T cells persisted in skin. Clinical improvement was linked to turnover of benign T cell clones but not to malignant T cell reduction. Benign T cells were associated with the Th2-recruiting chemokine CCL18 before therapy and with the Th1-recruiting chemokines CXCL9, CXCL10, and CXCL11 after therapy, suggesting a switch from Th2 to Th1. Inflammation was correlated with OX40L and CD40L gene expression; immunostaining localized these receptors to CCL18-expressing c-Kit+ dendritic cells that clustered together with CD40+OX40+ benign and CD40+CD40L+ malignant T cells, creating a proinflammatory synapse in skin. Our data suggest that visible inflammation in CTCL results from the recruitment and activation of benign T cells by c-Kit+OX40L+CD40L+ dendritic cells and that this activation may provide tumorigenic signals. Targeting c-Kit, OX40, and CD40 signaling may be novel therapeutic avenues for the treatment of MF.

Role of Dysregulated Cytokine Signaling and Bacterial Triggers in the Pathogenesis of Cutaneous T-Cell Lymphoma

Cutaneous T-cell lymphoma is a heterogeneous group of lymphomas characterized by the accumulation of malignant T cells in the skin. The molecular and cellular etiology of this malignancy remains enigmatic, and what role antigenic stimulation plays in the initiation and/or progression of the disease remains to be elucidated. Deep sequencing of the tumor genome showed a highly heterogeneous landscape of genetic perturbations, and transcriptome analysis of transformed T cells further highlighted the heterogeneity of this disease. Nonetheless, using data harvested from high-throughput transcriptional profiling allowed us to develop a reliable signature of this malignancy. Focusing on a key cytokine signaling pathway previously implicated in cutaneous T-cell lymphoma pathogenesis, JAK/STAT signaling, we used conditional gene targeting to develop a fully penetrant small animal model of this disease that recapitulates many key features of mycosis fungoides, a common variant of cutaneous T-cell lymphoma. Using this mouse model, we show that T-cell receptor engagement is critical for malignant transformation of the T lymphocytes and that progression of the disease is dependent on microbiota.