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

Ionizing radiation improves skin bacterial dysbiosis in cutaneous T-cell lymphoma

Introduction

Cutaneous T-cell lymphoma (CTCL) is closely associated with the host microbiome. While recent evidence suggests that shifts in specific bacterial taxa are associated with response to UV-B, a form of non-ionizing radiation, the impact of ionizing radiation (IR) has not been investigated.

Methods

16S rRNA and tuf gene amplicon sequencing were performed on DNA extracted from swabs of lesional/non-lesional skin of 12 CTCL patients before/after TSEBT or local IR and from 25 matched healthy controls (HC). Microbial diversity and taxonomic profiles were analyzed.

Results

Radiation exposure increased CTCL skin α-diversity to levels approximating HC. TSEBT appeared to carry the greatest effect compared to local IR. Both α and β-diversity differed significantly post versus pre-IR for TSEBT, but not for local IR. IR was associated with decreases in known pathogenic bacteria such as Streptococcus and S. aureus and increases in healthy commensal bacteria such as Anaerococcus, Bifidobacterium and commensal staphylococci including S. pettenkoferi. Substantially more taxa shifts were seen with TSEBT versus local IR.

Discussion

IR not only eliminates CTCL lesions via induction of apoptosis, but also facilitates skin barrier restoration and recolonization of bacterial taxa associated with a healthy skin microbiome. Local IR does not have as strong an effect on the skin microbiome as TSEBT. As skin microbiota act as immunomodulators with local and potentially systemic influence, TSEBT may also improve CTCL lesions via global effects on the skin microbiome. Future larger-scale studies are required to fully elucidate the relationship between cutaneous microbes and IR treatment in CTCL.

Deciphering the Etiologies of Adult Erythroderma: An Updated Guide to Presentations, Diagnostic Tools, Pathophysiologies, and Treatments

Erythroderma, an inflammatory skin condition characterized by widespread erythema with variable degrees of exfoliation, pustulation, or vesiculobullous formation, is associated with high morbidity and mortality. Determining the underlying cause of erythroderma frequently presents a diagnostic challenge, which may contribute to the condition's relatively poor prognosis. This review covers the clinical presentation, pathophysiology, diagnosis, and treatment of erythroderma. It discusses similarities and differences among the many underlying etiologies of the condition and differences between erythrodermic and non-erythrodermic presentations of the same dermatosis. Finally, this article explores current research that may provide future tools in the diagnosis and management of erythroderma.

Atypical Cutaneous Manifestation of Mycosis Fungoides: A Case Report

Mycosis fungoides (MF) is a cutaneous T-cell lymphoma (CTCL) that is characterized by atypical CD4+ T-cell aggregates in the epidermis. It is typically divided into three clinical phases, which consist of the patches, plaques, and tumor stages. There have been atypical manifestations of MF described in the literature, and it is hypothesized that the skin microbiota plays a role in the skin phenotype of MF patients. Here, we describe an MF patient with multiple, large, ulcerated, and purulent lesions that developed after she swam in the ocean. Our patient was found to have a unique set of bacteria isolated from the wound.

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.

Eradication of skin microbiota restores cytokine production and release in polymorphic light eruption

Polymorphic light eruption (PLE) has been mechanistically linked to cytokine abnormalities. Emerging preclinical evidence posits the skin microbiome as a critical modulator of ultraviolet (UV)-induced cytokine expression, thereby influencing subsequent immune responses. This intricate relationship remains underexplored in the context of PLE. Hence, we investigated the differential responses between disinfected and non-disinfected skin following both single and repetitive exposures to solar-simulated UV radiation in patients with PLE. An experimental, half-body pilot study was conducted involving six PLE patients and 15 healthy controls. Participants' skin was exposed to single and multiple doses of solar-simulated UV radiation, both in disinfected and in non-disinfected skin areas. The co-primary outcomes were PLE score and cytokine expression in blister fluid analysed through OLINK proteomic profiling. Secondary outcomes were erythema, pigmentation, induction of apoptotic cells in vacuum-generated suction blisters, and density of infiltrate in skin biopsies of PLE patients. Among the 71 cytokines analysed, baseline expression levels of 20 specific cytokines-integral to processes such as apoptosis, inflammation, immune cell recruitment, cellular growth, and differentiation-were significantly impaired in PLE patients compared with healthy controls. Notably, skin disinfection reversed the observed cytokine imbalances following a single UV exposure at the minimal erythema dose (MED) level and exhibited even more pronounced effects after multiple UV exposures. However, no significant differences were evident in PLE score, erythema, pigmentation, or rates of apoptotic cell induction upon UV radiation. These findings provide evidence for UV-driven cytokine regulation by the skin microbiota and imply microbiome involvement in the PLE immune response.

Cutaneous T-Cell Lymphoma and Microbiota: Etiopathogenesis and Potential New Therapeutic Targets

Objective

To review the scientific literature related to human microbiota and cutaneous T-cell lymphoma. Methodology. An exploratory and systematic review of the articles retrieved from the bibliographic databases MEDLINE (PubMed), Embase, The Cochrane Library, and Scopus, published in the last 10 years with the following descriptors: "lymphoma, T-cell, cutaneous," "microbiota," "Mycosis Fungoides," "Sézary Syndrome," "lymphoma, primary cutaneous anaplastic large cell," "Lymphomatoid Papulosis" and "Microbiota," "microbiota," "Microbial Community," and "Microbial Communities."

Results

Of the 87 references retrieved, after applying the inclusion and exclusion criteria, 21 articles were selected. Most studies linking cutaneous T-cell lymphoma and the microbiota focus on the cutaneous microbiome, with Staphylococcus aureus being the main related agent. Skin colonization by this bacterium could be involved in the hyperactivation of the STAT3 inflammatory pathway and in the overproduction of IL-17, both of which are widely related to the development of more aggressive and advanced forms of cutaneous T-cell lymphoma. We also found evidence of a possible relationship between intestinal dysbiosis and the development of cutaneous T-cell lymphoma, observing a decrease in taxonomic variability and an increase in certain genera such as Prevotella in the intestinal microbiome of patients with cutaneous T-cell lymphoma. The possible etiopathogenic mechanism underlying this relationship could be explained by an increase in systemic cytokine release, promoting the hyperactivation of STAT3 at the skin level.

Conclusion

There appears to be a relationship between cutaneous T-cell lymphoma and the cutaneous and intestinal microbiome, as well as a possible pathophysiological pathway involved. The possible modulation of the cutaneous and intestinal microbiome or the action on the signaling inflammatory pathway, using pharmacological tools such as JAK inhibitors or IL-17 inhibitors in the latter case, could open the possibility for future therapeutic studies for cutaneous T-cell lymphoma.

Skin swabs in the skin lymphoma clinic: from swab to treatment

The skin microbiome in cutaneous T-cell lymphoma (CTCL) is a growing area of research. Previous studies have highlighted the possibility of microbial dysbiosis in chronic inflammation and malignant transformation in CTCL. This single, tertiary centre study highlights the importance of routine skin swab use in the management of patients with CTCL and suggests future research developments.

Involvement of cutavirus in a subset of patients with cutaneous T-cell lymphoma with an unfavorable outcome

BACKGROUND

European studies suggest an association between cutavirus (CuV) and cutaneous T-cell lymphoma (CTCL); however, the worldwide prevalence of CuV in patients with CTCL and its prognostic impact remain unknown.

METHODS

We investigated the prevalence and viral loads of CuV DNA using biopsy specimens from the lesional skins of 141 Japanese patients with cutaneous malignancies, including 55 patients with various types of CTCL.

RESULTS

CuV DNA was detected significantly more frequently in biopsies from patients with mycosis fungoides (MF) (38% [13/34]; the most common subtype of CTCL) than in those from patients with other cutaneous malignancies (6% [6/107]; P<0.001). The viral-load range in patients with CuV DNA-positive MF was 23-3922 copies/10³ cells and 8-65 copies/μg of DNA. A phylogenetic analysis using the partial sequences of the CuV viral capsid protein 1 (VP1)/VP2 genes revealed that the CuV sequences identified here were clustered in a Japanese-specific clade distinct from that comprising CuV sequences from European patients with MF. Kaplan-Meier curves and a log-rank test showed that CuV positivity was associated with a shorter disease-specific survival in patients with MF (P = 0.031), whereas no significant difference in overall survival was observed (P = 0.275). No significant correlation was observed between CuV DNA load and survival in patients with CuV-positive MF.

CONCLUSIONS

Our results suggest that CuV is associated with MF in a subset of Japanese patients. Large-scale prospective studies are warranted to clarify the role of CuV status, especially regarding the viral genotype, on adverse outcomes in patients with CuV-positive MF.