Regulatory T Cells Mediate Local Immunosuppression in Lymphedema

Ultrasound-Mediated Piezoelectric Microneedles Regulating Macrophage Polarization and Remodeling Pathological Microenvironment for Lymphedema Improvement

Lymphedema, a severe and complex inflammatory disease caused by lymphatic system insufficiency and impeded lymphatic drainage that causes an enormous physical and psychological burden on patients and may even lead to death, has long been a challenging issue in the medical field. Clinically, conventional approaches including surgical treatment and conservative treatment have been employed for lymphedema therapy, but their curative effect is still unsatisfactory because of high operational difficulty, high cost, and long-term reliance. In this study, a novel kind of piezoelectric microneedle driven by ultrasound (US) is proposed to regulate macrophage polarization and remodel the pathological inflammatory microenvironment in a noninvasive manner, thereby promoting lymphatic regeneration and improving lymphedema. US-mediated piezoelectric microneedles can significantly enhance the anti-inflammatory M2-type polarization of macrophages while suppressing pro-inflammatory M1-type polarization in vitro. Enhancements in macrophage M2 polarization can trigger increased secretion of anti-inflammatory factors (e.g., IL-4, IL-10, and Arg-1) that promote inflammatory microenvironment remodeling and immune rebalancing. In a mouse-tail lymphedema model, a higher proportion of M2 macrophage polarization marker CD206 is observed accompanied by normal lymphangiogenesis and lymphedema subsiding following piezoelectric microneedles with US stimulation treatment. Additionally, based on RNA sequencing and mechanistic investigation, it was revealed that US-mediated piezoelectric microneedles can activate signaling pathways related to M2 macrophage polarization that regulate inflammatory responses and improve lymphatic function, consequently alleviating lymphedema. Collectively, this study provides a new strategy for lymphedema therapy in a noninvasive and drug-free manner as well as a potent tool to manipulate macrophages for other immunological diseases.

Anti-CTLA4 treatment reduces lymphedema risk potentially through a systemic expansion of the FOXP3+ Treg population

Secondary lymphedema is a common sequel of oncologic surgery and presents a global health burden still lacking pharmacological treatment. The infiltration of the lymphedematous extremities with CD4+T cells influences lymphedema onset and emerges as a promising therapy target. Here, we show that the modulation of CD4+FOXP3+CD25+regulatory T (Treg) cells upon anti-CTLA4 treatment protects against lymphedema development in patients with melanoma and in a mouse lymphedema model. A retrospective evaluation of a melanoma patient registry reveals that anti-CTLA4 reduces lymphedema risk; in parallel, anti-CTLA4 reduces edema and improves lymphatic function in a mouse-tail lymphedema model. This protective effect of anti-CTLA4 correlates with a systemic expansion of Tregs, both in the animal model and in patients with melanoma. Our data thus show that anti-CTLA4 with its lymphedema-protective and anti-tumor properties is a promising candidate for more diverse application in the clinics.

The Function of T Cell Immunity in Lymphedema: A Comprehensive Review

Lymphedema is a debilitating disease characterized by extremity edema, fibroadipose deposition, impaired lymphangiogenesis, and dysfunctional lymphatics, often with lymphatic injury secondary to the treatment of malignancies. Emerging evidence has shown that immune dysfunction regulated by T cells plays a pivotal role in development of lymphedema. Specifically, Th1, Th2, Treg, and Th17 cells have been identified as critical regulators of pathological changes in lymphedema. In this review, our aim is to provide an overview of the current understanding of the roles of CD4+ T cells, including Th1, Th2, Treg, and Th17 subsets, in the progression of lymphedema and to discuss associated therapies targeting T cell inflammation for management of lymphedema.

Profound and selective lymphopaenia in primary lymphatic anomaly patients demonstrates the significance of lymphatic-lymphocyte interactions

Introduction

The lymphatic system has a pivotal role in immune homeostasis. To better understand this, we investigated the impact of Primary Lymphatic Anomalies (PLA) on lymphocyte numbers and phenotype.

Methods

The study comprised (i) a retrospective cohort: 177 PLA subjects from the National Primary Lymphatic Anomaly Register with clinical and laboratory data, and (ii) a prospective cohort: 28 patients with PLA and 20 healthy controls. Patients were subdivided using established phenotypic diagnostic categories and grouped into simplex (localised tissue involvement only) and systemic (involvement of central lymphatics). Further grouping variables included genital involvement and the likelihood of co-existent intestinal lymphangiectasia. Haematology laboratory parameters were analysed in both cohorts. In the prospective cohort, prospective blood samples were analysed by flow cytometry for markers of proliferation, differentiation, activation, skin-homing, and for regulatory (CD4+Foxp3+) T cells (Treg).

Results

In patients with PLA, lymphopaenia was frequent (22% of subjects), affected primarily the CD4+ T cell subset, and was more severe in subjects with systemic versus simplex patterns of disease (36% vs 9% for lymphopaenia; 70% vs 33% for CD4+ cells). B cells, NK cells and monocytes were better conserved (except in GATA2 deficiency characterised by monocytopaenia). Genital oedema and likelihood of concomitant intestinal lymphangiectasia independently predicted CD4+ T cell depletion. Analysing CD4+ and CD8+ T cells by differentiation markers revealed disproportionate depletion of naïve cells, with a skewing towards a more differentiated effector profile. Systemic PLA conditions were associated with: increased expression of Ki67, indicative of recent cell division, in naïve CD4+, but not CD8+ T cells; increased levels of activation in CD4+, but not CD8+ T cells; and an increased proportion of Treg. Skin-homing marker (CCR10, CLA and CCR4) expression was reduced in some patients with simplex phenotypes.

Discussion

Patients with PLA who have dysfunctional lymphatics have a selective reduction in circulating lymphocytes which preferentially depletes naïve CD4+ T cells. The presence of systemic disease, genital oedema, and intestinal lymphangiectasia independently predict CD4 lymphopaenia. The association of this depletion with immune activation and increased circulating Tregs suggests lymphatic-lymphocyte interactions and local inflammatory changes are pivotal in driving immunopathology.

Peripheral T cell profiling reveals downregulated exhaustion marker and increased diversity in lymphedema post-lymphatic venous anastomosis

Lymphedema is a progressive condition accompanying cellulitis and angiosarcoma, suggesting its association with immune dysfunction. Lymphatic venous anastomosis (LVA) can provide relief from cellulitis and angiosarcoma. However, the immune status of peripheral T cells during lymphedema and post-LVA remains poorly understood. Using peripheral blood T cells from lymphedema, post-LVA, and healthy controls (HCs), we compared the profile of T cell subsets and T cell receptor (TCR) diversity. PD-1⁺ Tim-3 ⁺ expression was downregulated in post-LVA compared with lymphedema. IFN-γ levels in CD4⁺PD-1⁺ T cells and IL-17A levels in CD4⁺ T cells were downregulated in post-LVA compared with lymphedema. TCR diversity was decreased in lymphedema compared with HCs; such TCR skewing was drastically improved in post-LVA. T cells in lymphedema were associated with exhaustion, inflammation, and diminished diversity, which were relieved post-LVA. The results provide insights into the peripheral T cell population in lymphedema and highlight the immune modulatory importance of LVA.

Lymphatic-draining nanoparticles deliver Bay K8644 payload to lymphatic vessels and enhance their pumping function

Dysfunction of collecting lymphatic vessel pumping is associated with an array of pathologies. S-(-)-Bay K8644 (BayK), a small-molecule agonist of L-type calcium channels, improves vessel contractility ex vivo but has been left unexplored in vivo because of poor lymphatic access and risk of deleterious off-target effects. When formulated within lymph-draining nanoparticles (NPs), BayK acutely improved lymphatic vessel function, effects not seen from treatment with BayK in its free form. By preventing rapid drug access to the circulation, NP formulation also reduced BayK's dose-limiting side effects. When applied to a mouse model of lymphedema, treatment with BayK formulated in lymph-draining NPs, but not free BayK, improved pumping pressure generated by intact lymphatic vessels and tissue remodeling associated with the pathology. This work reveals the utility of a lymph-targeting NP platform to pharmacologically enhance lymphatic pumping in vivo and highlights a promising approach to treating lymphatic dysfunction.

The Vicious Circle of Stasis, Inflammation, and Fibrosis in Lymphedema

SUMMARY

Lymphedema is a progressive disease of the lymphatic system arising from impaired lymphatic drainage, accumulation of interstitial fluid, and fibroadipose deposition. Secondary lymphedema resulting from cancer treatment is the most common form of the disease in developed countries, affecting 15% to 40% of patients with breast cancer after lymph node dissection. Despite recent advances in microsurgery, outcomes remain variable and, in some cases, inadequate. Thus, development of novel treatment strategies is an important goal. Research over the past decade suggests that lymphatic injury initiates a chronic inflammatory response that regulates the pathophysiology of lymphedema. T-cell inflammation plays a key role in this response. In this review, the authors highlight the cellular and molecular mechanisms of lymphedema and discuss promising preclinical therapies.

Keratinocytes coordinate inflammatory responses and regulate development of secondary lymphedema

Epidermal changes are histological hallmarks of secondary lymphedema, but it is unknown if keratinocytes contribute to its pathophysiology. Using clinical lymphedema specimens and mouse models, we show that keratinocytes play a primary role in lymphedema development by producing T-helper 2 (Th2) -inducing cytokines. Specifically, we find that keratinocyte proliferation and expression of protease-activated receptor 2 (PAR2) are early responses following lymphatic injury and regulate the expression of Th2-inducing cytokines, migration of Langerhans cells, and skin infiltration of Th2-differentiated T cells. Furthermore, inhibition of PAR2 activation with a small molecule inhibitor or the proliferation inhibitor teriflunomide (TF) prevents activation of keratinocytes stimulated with lymphedema fluid. Finally, topical TF is highly effective for decreasing swelling, fibrosis, and inflammation in a preclinical mouse model. Our findings suggest that lymphedema is a chronic inflammatory skin disease, and topically targeting keratinocyte activation may be a clinically effective therapy for this condition.

Skin microbiome alterations in upper extremity secondary lymphedema

Lymphedema is a chronic condition that commonly occur from lymphatic injury following surgical resection of solid malignancies. While many studies have centered on the molecular and immune pathways that perpetuate lymphatic dysfunction, the role of the skin microbiome in lymphedema development remains unclear. In this study, skin swabs collected from normal and lymphedema forearms of 30 patients with unilateral upper extremity lymphedema were analyzed by 16S ribosomal RNA sequencing. Statistical models for microbiome data were utilized to correlate clinical variables with microbial profiles. Overall, 872 bacterial taxa were identified. There were no significant differences in microbial alpha diversity of the colonizing bacteria between normal and lymphedema skin samples (p = 0.25). Notably, for patients without a history of infection, a one-fold change in relative limb volume was significantly associated with a 0.58-unit increase in Bray-Curtis microbial distance between paired limbs (95%CI = 0.11,1.05, p = 0.02). Additionally, several genera, including Propionibacterium and Streptococcus, demonstrated high variability between paired samples. In summary, we demonstrate high compositional heterogeneity in the skin microbiome in upper extremity secondary lymphedema, supporting future studies into the role of host-microbe interactions on lymphedema pathophysiology.

Acquired lymphedema: Molecular contributors and future directions for developing intervention strategies

Lymphedema is a debilitating chronic disease that mostly develops as an adverse reaction to cancer treatment modalities such as chemotherapy, surgery, and radiotherapy. Lymphedema also appears to be a deteriorating consequence of roundworm infections, as best represented by filariasis. According to its origin, lymphedema is classified as primary lymphedema and acquired lymphedema. The latter is an acquired condition that, hitherto, received a considerably low attention owing to the less number of fatal cases been reported. Notably, despite the low mortality rate in lymphedema, it has been widely reported to reduce the disease-free survival and thus the quality of life of affected patients. Hence, in this review, we focused on acquired lymphedema and orchestration of molecular interplays associated with either stimulation or inhibition of lymphedema development that were, in vast majority, clearly depicted in animal models with their specific and distinct technical approaches. We also discussed some recent progress made in phytochemical-based anti-lymphedema intervention strategies and the specific mechanisms underlying their anti-lymphedema properties. This review is crucial to understand not only the comprehensive aspects of the disease but also the future directions of the intervention strategies that can address the quality of life of affected patients rather than alleviating apparent symptoms only.

A Prospective Study on the Safety and Efficacy of Vascularized Lymph Node Transplant

PURPOSE

While vascularized lymph node transplant (VLNT) has gained popularity, there are a lack of prospective long-term studies and standardized outcomes. The purpose of this study was to evaluate the safety and efficacy of VLNT using all available outcome measures.

METHODS

This was a prospective study on all consecutive patients who underwent VLNT. Outcomes were assessed with 2 patient-reported outcome metrics, limb volume, bioimpedance, need for compression, and incidence of cellulitis.

RESULTS

There were 89 patients with the following donor sites: omentum (73%), axilla (13%), supraclavicular (7%), groin (3.5%). The mean follow-up was 23.7±12 months. There was a significant improvement at 2 years postoperatively across all outcome measures: 28.4% improvement in the Lymphedema Life Impact Scale, 20% average reduction in limb volume, 27.5% improvement in bioimpedance score, 93% reduction in cellulitis, and 34% of patients no longer required compression. Complications were transient and low without any donor site lymphedema.

CONCLUSIONS

VLNT is a safe and effective treatment for lymphedema with significant benefits fully manifesting at 2 years postoperatively. Omentum does not have any donor site lymphedema risk making it an attractive first choice.

Current Advancements in Animal Models of Postsurgical Lymphedema: A Systematic Review

Significance: Secondary lymphedema is a debilitating disease caused by lymphatic dysfunction characterized by chronic swelling, dysregulated inflammation, disfigurement, and compromised wound healing. Since there is no effective cure, animal model systems that support basic science research into the mechanisms of secondary lymphedema are critical to advancing the field. Recent Advances: Over the last decade, lymphatic research has led to the improvement of existing animal lymphedema models and the establishment of new models. Although an ideal model does not exist, it is important to consider the strengths and limitations of currently available options. In a systematic review adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we present recent developments in the field of animal lymphedema models and provide a concise comparison of ease, cost, reliability, and clinical translatability. Critical Issues: The incidence of secondary lymphedema is increasing, and there is no gold standard of treatment or cure for secondary lymphedema. Future Directions: As we iterate and create animal models that more closely characterize human lymphedema, we can achieve a deeper understanding of the pathophysiology and potentially develop effective therapeutics for patients.

[Autologous Breast Reconstruction in Conjuction with Lymphatic Microsurgery in Breast Cancer-Related Lymphedema]

Breast cancer-related lymphedema of the upper extremity is the most significant non-oncological complication of tumour therapy, leading to functional impairment and impacting patients' quality of life. Autologous breast reconstruction per se effectively reduces incidence and stage of lymphedema after breast cancer treatment by surgical angiogenesis. In addition, modern surgical techniques for treating lymphedema are effective in reducing limb volume, circumference and functional impairment, and improving patients' quality of life, body image, integrity and local immunocompetence. Reconstructive surgery, including lymphovenous anastomoses (LVA) and vascularised lymph node transfer (VLNT), have been shown to rearrange or restore lymphatic flow and prevent stage progression. For patients with breast cancer-related lymphedema after mastectomy, autologous breast reconstruction in conjunction with lymphatic microsurgery using VLNT, LVA or a combination of these procedures offers the option of holistic and single-stage restoration in modern senology. Extensive scar release in the axilla is a crucial component of the surgical technique, aiming to prepare the recipient bed for the VLN transplant and to allow for the functional recruitment of remaining lymph vessels of the upper extremity. This article presents the indications, preoperative diagnostic evaluation, surgical techniques and precautions, complications and results of combined lymphatic and breast restoration.

Current Understanding of Pathological Mechanisms of Lymphedema

Significance: Lymphedema is a common disease that affects hundreds of millions of people worldwide with significant financial and social burdens. Despite increasing prevalence and associated morbidities, the mainstay treatment of lymphedema is largely palliative without an effective cure due to incomplete understanding of the disease. Recent Advances: Recent studies have described key histological and pathological processes that contribute to the progression of lymphedema, including lymphatic stasis, inflammation, adipose tissue deposition, and fibrosis. This review aims to highlight cellular and molecular mechanisms involved in each of these pathological processes. Critical Issues: Despite recent advances in the understanding of the pathophysiology of lymphedema, cellular and molecular mechanisms underlying the disease remains elusive due to its complex nature. Future Directions: Additional research is needed to gain a better insight into the cellular and molecular mechanisms underlying the pathophysiology of lymphedema, which will guide the development of therapeutic strategies that target specific pathology of the disease.

Case study: night compression use in a patient with Milroy's disease

AIM

Lymphoedema is associated with dysfunctional lymphatics, tissue fibrosis and inflammatory changes in the skin and local tissue. Ensuring compression supports tissue health is crucial to managing lymphoedema. Providing patients with safe compression which enhances their tissue health is paramount when supporting their 24-hour self-management regimens. This case study explores the use of a new compression garment in two sitting positions in an adult with primary lymphoedema.

METHOD

An 18-year-old female (body mass index 25.2 kg/m²) with Milroy's disease was recruited. She attended two separate 1-hour sessions to evaluate tissue oxygenation (StO₂) in chair-sitting and long-sitting (sitting up with a supported back and legs horizontal) positions. Following removal of her usual class 2 (20-30 mmHg) flat-knit compression hosiery, StO₂ was recorded for 20 minutes: pre-, during and post the application of an adjustable compression garment (Lohmann & Rauscher) to the right leg.

RESULTS

In the long-sitting position, StO₂ levels started high at baseline (94.5%), and were relatively maintained both during and post-a short 20-minute intervention (94.1%). In the chair-sitting position, StO₂ levels were significantly lower at baseline (52%), showing a 77% increase during the intervention (92%), followed by a small 9% decrease post-intervention (83.7%).

CONCLUSION

This compression garment significantly increased StO₂ levels in the chair-sitting position, while maintaining the effects of the patient's compression stockings, in the long-sitting position. Similar to non-lymphoedematous limbs, the patient's normal prescription hosiery maintains StO₂. Through implementation of the short intervention sessions, night compression garments may have the potential to improve tissue health in individuals with primary lymphoedema, encouraging self-management and offering a potential night compression solution where the need arises in a 24-hour management plan.

TGF-β1 mediates pathologic changes of secondary lymphedema by promoting fibrosis and inflammation

Background

Secondary lymphedema is a common complication of cancer treatment, and previous studies have shown that the expression of transforming growth factor‐beta 1 (TGF‐β1), a pro‐fibrotic and anti‐lymphangiogenic growth factor, is increased in this disease. Inhibition of TGF‐β1 decreases the severity of the disease in mouse models; however, the mechanisms that regulate this improvement remain unknown.

Methods

Expression of TGF‐β1 and extracellular matrix molecules (ECM) was assessed in biopsy specimens from patients with unilateral breast cancer‐related lymphedema (BCRL). The effects of TGF‐β1 inhibition using neutralizing antibodies or a topical formulation of pirfenidone (PFD) were analyzed in mouse models of lymphedema. We also assessed the direct effects of TGF‐β1 on lymphatic endothelial cells (LECs) using transgenic mice that expressed a dominant‐negative TGF‐β receptor selectively on LECs (LEC^DN‐RII).

Results

The expression of TGF‐β1 and ECM molecules is significantly increased in BCRL skin biopsies. Inhibition of TGF‐β1 in mouse models of lymphedema using neutralizing antibodies or with topical PFD decreased ECM deposition, increased the formation of collateral lymphatics, and inhibited infiltration of T cells. In vitro studies showed that TGF‐β1 in lymphedematous tissues increases fibroblast, lymphatic endothelial cell (LEC), and lymphatic smooth muscle cell stiffness. Knockdown of TGF‐β1 responsiveness in LEC^DN‐RII resulted in increased lymphangiogenesis and collateral lymphatic formation; however, ECM deposition and fibrosis persisted, and the severity of lymphedema was indistinguishable from controls.

Conclusions

Our results show that TGF‐β1 is an essential regulator of ECM deposition in secondary lymphedema and that inhibition of this response is a promising means of treating lymphedema.

Lymph Leakage Promotes Immunosuppression by Enhancing Anti-Inflammatory Macrophage Polarization

Lymphatic vasculature is a network of capillaries and vessels capable of draining extracellular fluid back to blood circulation and to facilitate immune cell migration. Although the role of the lymphatic vasculature as coordinator of fluid homeostasis has been extensively studied, the consequences of abnormal lymphatic vasculature function and impaired lymph drainage have been mostly unexplored. Here, by using the Prox1+/- mice with defective lymphatic vasculature and lymphatic leakage, we provide evidence showing that lymph leakage induces an immunosuppressive environment by promoting anti-inflammatory M2 macrophage polarization in different inflammatory conditions. In fact, by using a mouse model of tail lymphedema where lymphatic vessels are thermal ablated leading to lymph accumulation, an increasing number of anti-inflammatory M2 macrophages are found in the lymphedematous tissue. Moreover, RNA-seq analysis from different human tumors shows that reduced lymphatic signature, a hallmark of lymphatic dysfunction, is associated with increased M2 and reduced M1 macrophage signatures, impacting the survival of the patients. In summary, we show that lymphatic vascular leakage promotes an immunosuppressive environment by enhancing anti-inflammatory macrophage differentiation, with relevance in clinical conditions such as inflammatory bowel diseases or cancer.

Erysipelas of the leg: A cross-sectional study of risk factors for recurrence

BACKGROUND

Erysipelas is a common infection of the superficial layer of skin. The main causative agent is group A β-hemolytic streptococci. One of the most challenging aspects of this disease is its high rate of recurrence.

OBJECTIVES

To identify risk factors for recurrence of erysipelas of the leg.

PATIENTS AND METHODS

We included in a cross-sectional study all patients hospitalized for erysipelas of the leg seen at the dermatology department of the Ibn Rochd University Hospital in Casablanca, Morocco, from January 2015 to April 2020. Patients were divided into two groups: those with a single episode (SE) and those with recurrent erysipelas (RE). These two groups were compared for clinical and laboratory characteristics, with particular focus on systemic and local risk factors.

RESULTS

The study included 270 patients, of whom 132 had SE and 138 had RE. Age, gender, hospital stay as well as laboratory findings did not differ significantly between the two groups. In multivariable analysis, cutaneous disruption [adjusted odds ratio (aOR)=1.9; 95% confidence interval (95% CI): 1.0-3.71], lymphedema [aOR=19.6; 95% CI: 8.0-57.2], and obesity [aOR=2.3; 95% CI: 1.1-5.2] were significantly associated with RE. Venous insufficiency and diabetes were not found to be associated with risk of recurrence.

CONCLUSION

Our results suggest that erysipelas is a potentially chronic disease and patients with identified local risk factors or obesity should be considered as exposed to recurrence and considered as targets for antibiotic prophylaxis and other preventive methods.

Crosstalk Between microRNAs and the Pathological Features of Secondary Lymphedema

Secondary lymphedema is characterized by lymphatic fluid retention and subsequent tissue swelling in one or both limbs that can lead to decreased quality of life. It often arises after loss, obstruction, or blockage of lymphatic vessels due to multifactorial modalities, such as lymphatic insults after surgery, immune system dysfunction, deposition of fat that compresses the lymphatic capillaries, fibrosis, and inflammation. Although secondary lymphedema is often associated with breast cancer, the condition can occur in patients with any type of cancer that requires lymphadenectomy such as gynecological, genitourinary, or head and neck cancers. MicroRNAs demonstrate pivotal roles in regulating gene expression in biological processes such as lymphangiogenesis, angiogenesis, modulation of the immune system, and oxidative stress. MicroRNA profiling has led to the discovery of the molecular mechanisms involved in the pathophysiology of auto-immune, inflammation-related, and metabolic diseases. Although the role of microRNAs in regulating secondary lymphedema is yet to be elucidated, the crosstalk between microRNAs and molecular factors involved in the pathological features of lymphedema, such as skin fibrosis, inflammation, immune dysregulation, and aberrant lipid metabolism have been demonstrated in several studies. MicroRNAs have the potential to serve as biomarkers for diseases and elucidation of their roles in lymphedema can provide a better understanding or new insights of the mechanisms underlying this debilitating condition.

[Bullous pemphigoid with unilateral sparing after axillary lymphadenectomy]

An 83-year-old woman presented to our outpatient clinic with bullous pemphigoid with a unilateral sparing of the left arm after axillary lymphadenectomy because of breast cancer. Cases of localized manifestations of bullous pemphigoid are mainly caused by lymphedema or radiation. The absence of blistering after lymphadenectomy is a rare and interesting manifestation. Pathophysiologically, blister formation may be attenuated or absent altogether due to decreased T‑cell activation and thus reduced inflammatory infiltrate because of the absence of peripheral lymph nodes.

Stewart-Treves syndrome and other cutaneous malignancies in the context of chronic lymphedema: a systematic review

INTRODUCTION

Angiosarcoma developing in chronically lymphedematous tissue, or Stewart-Treves syndrome (STS), is a rare and lethal complication of lymphedema. This systematic review summarizes characteristics and outcomes of STS and other cutaneous malignancies arising in chronic lymphedema.

METHODS

MEDLINE and EMBASE databases were searched on February 19th, 2021, to identify 200 articles included in the analysis.

RESULTS

Of 369 included patients, 89.7% (n = 331/369) had STS and 10.3% (n = 38/369) had other associated malignancies. Mean age of onset was 61.2 years, and 85.9% (n = 317/369) of cases were female. Common risk factors were previous cancer history (69.8%, n = 258/369) and radiation history (53.7%, n = 198/369). Lymphedema was most commonly attributed to surgical causes (68.3%, n = 252/369). STS begins on average 14.9 years after lymphedema with mortality of 53.9% (n = 178/331) and remission rate of 16.1% (n = 53/331). Other malignancies begin on average 23.7 years after lymphedema, with mortality of 10.5% (n = 4/38) and remission rate of 31.6% (n = 12/38). STS and other malignancies had 5-year survivals of 22.4% and 65.2%, respectively (P = 0.00145). For all patients, patients initially treated with excision had the best survival (median: 48 months, 5-year survival: 43.3%) and radiotherapy had the worst survival (median: 10 months, 5-year survival: 6.5%) (P = 0.0141).

CONCLUSION

Malignancy can appear in lymphedematous tissue many years after lymphedema onset. STS has poorer prognosis compared to other malignancies. Further research should be conducted to better understand the causes, risk factors, and management of this phenomenon.

Factors Associated With Lymphedema in Women With Node-Positive Breast Cancer Treated With Neoadjuvant Chemotherapy and Axillary Dissection

Importance

Most lymphedema studies include a heterogeneous population and focus on patients treated with adjuvant chemotherapy.

Objective

To examine factors associated with lymphedema after neoadjuvant chemotherapy (NAC) and axillary lymph node dissection in women with node-positive breast cancer.

Design, Setting, and Participants

This cohort study included data from 701 women 18 years or older with cT0-T4N1-2M0 breast cancer with documented axillary nodal metastasis at diagnosis who were enrolled in the American College of Surgeons Oncology Group Z1071 (Alliance for Clinical Trials in Oncology) trial, which took place from January 1, 2009, to December 31, 2012. Data analysis was performed from January 11, 2018, to November 9, 2018.

Interventions

All participants received NAC, breast operation, and axillary lymph node dissection. Participants underwent prospective arm measurements and symptom assessment after NAC completion and at 6-month intervals to 36 months postoperatively.

Main Outcomes and Measures

Factors associated with lymphedema were defined as self-reported arm heaviness or swelling (lymphedema symptoms) or an arm volume increase of 10% or more (V10) or 20% or more (V20).

Results

A total of 486 patients (mean [SD] age, 50.1 [10.8] years) were included in this study. Median follow-up for the 3 measures was 2.2 to 3.0 years. Cumulative lymphedema incidence at 3 years was 37.8% (95% CI, 33.1%-43.2%) for lymphedema symptoms, 58.4% (95% CI, 53.2%-64.1%) for V10, and 36.9% (95% CI, 31.9%-42.6%) for V20. Increasing body mass index (hazard ratio [HR], 1.04; 95% CI, 1.01-1.06) and NAC for 144 days or longer (HR, 1.48; 95% CI, 1.01-2.17) were associated with lymphedema symptoms. The V20 incidence was higher among patients who received NAC for 144 days or longer (HR, 1.79; 95% CI, 1.19-2.68). The V10 incidence was highest in patients with 30 nodes or more removed (HR, 1.70; 95% CI, 1.15-2.52) and increased with number of positive nodes (HR, 1.03; 95% CI, 1.00-1.06). On multivariable analysis, obesity was significantly associated with lymphedema symptoms (HR, 1.03; 95% CI, 1.01-1.06), and NAC length was significantly associated with V20 (HR, 1.74; 95% CI, 1.15-2.62).

Conclusions and Relevance

In this study, longer NAC duration and obesity were associated with increased lymphedema incidence, suggesting that patients in these groups may benefit from enhanced prospective lymphedema surveillance.

Histopathologic Features of Lymphedema: A Molecular Review

An estimated 5 million people in the United States are affected by secondary lymphedema, with most cases attributed to malignancies or malignancy-related treatments. The pathogenesis of secondary lymphedema has historically been attributed to lymphatic injury or dysfunction; however, recent studies illustrate the complexity of lymphedema as a disease process in which many of its clinical features such as inflammation, fibrosis, adipogenesis, and recurrent infections contribute to on-going lymphatic dysfunction in a vicious cycle. Investigations into the molecular underpinning of these features further our understanding of the pathophysiology of this disease and suggests new therapeutics.

The Unresolved Pathophysiology of Lymphedema

Lymphedema is the clinical manifestation of impaired lymphatic transport. It remains an under-recognized and under-documented clinical condition that still lacks a cure. Despite the substantial advances in the understanding of lymphatic vessel biology and function in the past two decades, there are still unsolved questions regarding the pathophysiology of lymphedema, especially in humans. As a consequence of impaired lymphatic drainage, proteins and lipids accumulate in the interstitial space, causing the regional tissue to undergo extensive and progressive architectural changes, including adipose tissue deposition and fibrosis. These changes are also associated with inflammation. However, the temporal sequence of these events, the relationship between these events, and their interplay during the progression are not clearly understood. Here, we review our current knowledge on the pathophysiology of lymphedema derived from human and animal studies. We also discuss the possible cellular and molecular mechanisms involved in adipose tissue and collagen accumulation during lymphedema. We suggest that more studies should be dedicated to enhancing our understanding of the human pathophysiology of lymphedema to pave the way for new diagnostic and therapeutic avenues for this condition.

Mouse tail models of secondary lymphedema: fibrosis gradually worsens and is irreversible

Although the mouse tail model of secondary lymphedema has been widely used in research, our knowledge regarding some of the characteristic changes in this model is lacking. Therefore, in the current study, we aimed to identify pathologic changes after surgery. Tail lymphedema was created in C57BL/6J mice by disconnecting both superficial and deep lymphatic vessels. The surgery resulted in chronic edema formation with the proliferation of subcutaneous adipose tissue, deposition of fibrotic tissue, and gradual increase in CD4⁺ T lymphocyte infiltration. Furthermore, dramatic expansion and an increased number of lymphatic vessels were observed postoperatively. Lymphatic reflux was established at least 8 weeks after surgery, as evidenced by staining of the scar from the surgical excision. In addition, tissue fibrosis was irreversible, although CD4⁺ T cell infiltration, tail swelling, and subcutaneous adipose hyperplasia were alleviated over time. We also show that necrosis could be effectively avoided by paying attention to several details in the modeling process. As animal models play a key role in exploring the pathophysiology of disease, our findings provide strong support for the study of lymphedema. The irreversibility of fibrosis suggests the importance of treating lymphedema by preventing fibrosis development.

Fibrosis and secondary lymphedema: chicken or egg?

Secondary lymphedema is a common complication of cancer treatment resulting in progressive fibroadipose tissue deposition, increased risk of infections, and, in rare cases, secondary malignancies. Until recently, the pathophysiology of secondary lymphedema was thought to be related to impaired collateral lymphatic formation after surgical injury. However, more recent studies have shown that chronic inflammation-induced fibrosis plays a key role in the pathophysiology of this disease. In this review, we will discuss the evidence supporting this hypothesis and summarize recent publications demonstrating that lymphatic injury activates chronic immune responses that promote fibrosis and lymphatic leakiness, decrease collecting lymphatic pumping, and impair collateral lymphatic formation. We will review how chronic mixed T-helper cell inflammatory reactions regulate this process and how this response may be used to design novel therapies for lymphedema.

Tumor Lymphatic Function Regulates Tumor Inflammatory and Immunosuppressive Microenvironments

Proliferation of aberrant, dysfunctional lymphatic vessels around solid tumors is a common histologic finding. Studies have shown that abnormalities in lymphatic function result in accumulation of inflammatory cells with an immunosuppressive profile. We tested the hypothesis that dysfunctional lymphatic vessels surrounding solid tumors regulate changes in the tumor microenvironment and tumor-specific immune responses. Using subcutaneously implanted mouse melanoma and breast cancer tumors in a lymphatic endothelial cell-specific diphtheria toxin receptor transgenic mouse, we found that local ablation of lymphatic vessels increased peritumoral edema, as compared with controls. Comparative analysis of the peritumoral fluid demonstrated increases in the number of macrophages, CD4⁺ inflammatory cells, F4/80⁺/Gr-1⁺ (myeloid-derived suppressor cells), CD4⁺/Foxp3⁺ (Tregs) immunosuppressive cells, and expression of inflammatory cytokines such as TNFα, IFNγ, and IL1β following lymphatic ablation. Tumors grown in lymphatic ablated mice exhibited reduced intratumoral accumulation of cytotoxic T cells and increased tumor PD-L1 expression, causing rapid tumor growth, compared with tumors grown in nonlymphatic-ablated mice. Our study suggests that lymphatic dysfunction plays a role in regulating tumor microenvironments and may be therapeutically targeted in combination with immunotherapy to prevent tumor growth and progression.

T helper 2 differentiation is necessary for development of lymphedema

T cells infiltrating lymphedematous tissues have a mixed T helper 1 (Th1) and Th2 differentiation profile. Treatment with neutralizing antibodies targeting cytokines that promote Th2 differentiation (interleukin 4 [IL-4] and IL-13) decreases the severity of lymphedema in preclinical models, suggesting that Th2 cells play a key role in the pathology of this disease. However, these previous studies do not address the contribution of Th1 cells and it remains unknown if IL-4 and IL-3 blockade acts primarily on T cells or decreases the pathological changes of lymphedema by other mechanisms. Therefore, this study sought to analyze the effect of lymphatic injury in transgenic mice with mutations that cause defects in Th1 and Th2 cell generation (T-bet knockout or T-betKO and STAT6 knockout or STAT6KO mice, respectively). Using both the mouse tail and popliteal lymph node dissection models of lymphedema, we show that Th2-deficient (STAT6KO) mice are protected from developing lymphedema, have decreased fibrosis, increased collateral vessel formation, and preserved collecting lymphatic vessel pumping function. In contrast, mice with defective Th1 cell generation (T-betKO) develop disease with the same severity as wild-type controls. Taken together, our results suggest that Th2 differentiation is necessary for development of lymphedema following lymphatic injury and that Th1 differentiation does not significantly contribute to the pathology of the disease. Such findings are important as immunotherapy directed at Th2 cells has been found to be effective in well-studied Th2-mediated diseases such as asthma and atopic dermatitis and may therefore be similarly useful for lymphedema management.

Regulation of Immune Function by the Lymphatic System in Lymphedema

The lymphatic vasculature has traditionally been thought to play a passive role in the regulation of immune responses by transporting antigen presenting cells and soluble antigens to regional lymph nodes. However, more recent studies have shown that lymphatic endothelial cells regulate immune responses more directly by modulating entry of immune cells into lymphatic capillaries, presenting antigens on major histocompatibility complex proteins, and modulating antigen presenting cells. Secondary lymphedema is a disease that develops when the lymphatic system is injured during surgical treatment of cancers or is damaged by infections. We have used mouse models of lymphedema in order to understand the effects of chronic lymphatic injury on immune responses and have shown that lymphedema results in a mixed T helper cell and T regulatory cell (Treg) inflammatory response. Prolonged T helper 2 biased immune responses in lymphedema regulate the pathology of this disease by promoting tissue fibrosis, inhibiting formation of collateral lymphatics, decreasing lymphatic vessel pumping capacity, and increasing lymphatic leakiness. Treg infiltration following lymphatic injury results from proliferation of natural Tregs and suppresses innate and adaptive immune responses. These studies have broad clinical relevance since understanding how lymphatic injury in lymphedema can modulate immune responses may provide a template with which we can study more subtle forms of lymphatic injury that may occur in physiologic conditions such as aging, obesity, metabolic tumors, and in the tumor microenvironment.

Small Numbers of CD4+ T Cells Can Induce Development of Lymphedema

BACKGROUND

CD4 T cells have been implicated in the pathology of lymphedema. Interestingly, however, there have been case reports of lymphedema development in patients with low levels of CD4 T cells because of immunosuppression. In this study, the authors sought to delineate the effect of relative CD4 T-cell deficiency on the development of lymphedema in a mouse model.

METHODS

A mouse model of relative CD4 T-cell deficiency was created through lethal total body irradiation of wild-type mice that then underwent bone marrow transplantation with progenitors harvested from CD4 knockout mice (wild-type/CD4 knockout). Irradiated CD4 knockout mice reconstituted with wild-type mouse-derived progenitors (CD4 knockout/wild-type), and unirradiated CD4 knockout and wild-type mice were used as controls. All mice underwent tail skin and lymphatic excision to induce lymphedema, and analysis was performed 6 weeks later.

RESULTS

Wild-type/CD4 knockout chimeras were not protected from developing lymphedema. Despite a global deficit in CD4 T cells, these mice had swelling, fibrosis, inflammation, and impaired lymphatic transport function indistinguishable from that in wild-type and CD4 knockout/wild-type mice. In contrast, unirradiated CD4 knockout mice had no features of lymphedema after lymphatic injury.

CONCLUSIONS

Relatively small numbers of bone marrow and peripheral CD4 T cells are sufficient to induce the development of lymphedema. These findings suggest that lymphatic injury results in expansion of CD4 T-cell populations in lymphedematous tissues.

Modulation of Immunity by Lymphatic Dysfunction in Lymphedema

The debilitating condition known as secondary lymphedema frequently occurs after lymphadenectomy and/or radiotherapy for the treatment of cancer. These therapies can damage lymphatic vessels leading to edema, fibrosis, inflammation and dysregulated adipogenesis, which result in profound swelling of an affected limb. Importantly, lymphedema patients often exhibit impaired immune function which predisposes them to a variety of infections. It is known that lymphadenectomy can compromise the acquisition of adaptive immune responses and antibody production; however the cellular mechanisms involved are poorly understood. Here we discuss recent progress in revealing the cellular and molecular mechanisms underlying poor immune function in secondary lymphedema, which has indicated a key role for regulatory T cells in immunosuppression in this disease. Furthermore, the interaction of CD4⁺ T cells and macrophages has been shown to play a role in driving proliferation of lymphatic endothelial cells and aberrant lymphangiogenesis, which contribute to interstitial fluid accumulation in lymphedema. These new insights into the interplay between lymphatic vessels and the immune system in lymphedema will likely provide opportunities for novel therapeutic approaches designed to improve clinical outcomes in this problematic disease.

Genomic Analyses Identify Recurrent Alterations in Immune Evasion Genes in Diffuse Large B-Cell Lymphoma, Leg Type

Cutaneous diffuse large B-cell lymphomas (DLBCLs) are aggressive lymphomas with a poor prognosis. To elucidate their genetic bases, we analyzed exome sequencing of 37 cutaneous DLBCLs, including 31 DLBCLs, leg type (DLBCL-LT) and 6 cutaneous DLBCLs-not otherwise specified (DLBCL-NOS). As reported previously, 77% of DLBCL-LT harbor NF-κB-activating MYD88 mutations. In nearly all MYD88-wild-type DLBCL-LT, we found cancer-promoting mutations that either activate the NF-κB pathway through alternative genes (NFKBIE or REL) or activate other canonical cancer pathways (BRAF, MED12, PIK3R1, and STAT3). After NF-κB, the second most commonly mutated pathway putatively enables immune evasion via mutations predicted to downregulate antigen processing (B2M, CIITA, HLA) or T-cell co-stimulation (CD58). DLBCL-LT have little genetic overlap with the genetically heterogeneous DLBCL-NOS. Instead, they resemble primary central nervous system and testicular large B-cell lymphomas (primary central nervous system lymphomas and primary testicular lymphomas). Like primary central nervous system lymphomas/primary testicular lymphomas, 40% of DLBCL-LT (vs. 0% of DLBCLs-not otherwise specified) harbored PDL1/PDL2 translocations, which lead to overexpression of PD-L1 or PD-L2 in 50% of the cases. Collectively, these data broaden our understanding of cutaneous DLBCLs and suggest novel therapeutic approaches (e.g., BRAF or PI3K inhibitors). Additionally, they suggest novel treatment paradigms, wherein DLBCL-LT can be targeted with strategies (e.g., immune checkpoint blockers) currently being developed for genomically similar primary central nervous system lymphomas/primary testicular lymphomas.