FOXP3 positive regulatory T-cells in cutaneous and systemic CD30 positive T-cell lymphoproliferations

Clinicopathologic and microenvironmental analysis of primary cutaneous CD30-positive lymphoproliferative disorders: a 26 year experience from an academic medical center in Brazil

Background

Primary cutaneous CD30+ lymphoproliferative disorders (pc-CD30-LPD) are a group of clonal T cell lymphoproliferative disorders that despite very similar tumor histology follow different and characteristic clinical courses, suggesting a homeostatic role of the tumor microenvironment. Little is known about tumor microenvironment and there is almost no literature about PD-L1 expression in pc-CD30-LPD.

Methods

This retrospective study presents a fully clinicopathologically characterized series of pc-CD30-LPDs from an academic medical center in Brazil, including 8 lymphomatoid papulomatosis (LyP), 9 primary cutaneous anaplastic large cell lymphoma (pcALCL) and 4 borderline lesions. All the cases were scored for FOXP3+ regulatory T-cells (Treg) and CD8+ cytotoxic tumor infiltrating lymphocytes (TIL) densities, as well as PD-L1 expression in tumor cells and tissue associated macrophages. The CD8+/FOXP3+ ratio was also evaluated.

Results

Among the 21 cases of pc-CD30-LPD, PD-L1 expression is frequent in both tumor cells and tissue associated macrophages in pc-CD30-LPD across categories, suggesting that the PD-L1 axis may be a common feature of pc-CD30-LPDs. While reactive T cell infiltrates vary widely from case to case, a common feature across pc-CD30-LPDs is higher density of CD8 than FOXP3 + T cells. The distribution of T cells within the lesions however differed between LyP and pcALCL: we found that LyP lesions tend to be permeated by CD8+ and FOXP3+ T cells, whereas pcALCL tend to be surrounded by a rim of CD8+ TIL and FOXP3+ Tregs with relatively lower density infiltrates in the center of the lesion.

Conclusions

LyP has a trend to have denser immune cells throughout the lesion, with higher FOXP3+ Treg and CD8+ TIL in the center than the edge comparing with pcALCL. PD-L1+ is frequent in tumor cells and tissue associated macrophages in pc-CD30-LPD. The differential distribution of CD8+ and FOXP3+ TILs in LyP as compared to pcALCL could provide a clue to the relapsing/remitting course of LyP as compared to the less frequent spontaneous regression of pcALCL.

Adult T-cell leukemia/lymphoma can be indistinguishable from other more common T-cell lymphomas. The University of Miami experience with a large cohort of cases

Adult T-cell leukemia/lymphoma, an aggressive T-cell neoplasm, is causally linked to human T-cell lymphotropic virus type 1 and based on this association has a distinct geographic distribution. In our United States-based practice, whose population is enriched for immigrants from human T-cell lymphotropic virus type 1 endemic areas, we have identified that a subset of adult T-cell leukemia/lymphoma, in the absence of human T-cell lymphotropic virus type 1 identification, are indistinguishable from other more common T-cell neoplasms. We retrospectively gathered serology results for anti-human T-cell lymphotropic virus type 1/2 antibody in patients diagnosed with T-cell neoplasms at our institution. A total of 220 human T-cell lymphotropic virus type 1/2 positive patients with T-cell neoplasms were identified; 199 (91%) were correctly classified as adult T-cell leukemia/lymphoma or provisionally as peripheral T-cell lymphoma (serology testing pending). Twenty-one cases (9%) were initially misclassified, including the following: 13 presenting with skin +/- peripheral blood involvement and misclassified as mycosis fungoides/Sezary syndrome; 7 with lymphomatous disease, absence of leukemic involvement, and diffuse CD30 expression, misclassified as ALK- negative anaplastic large-cell lymphoma; 1 thought to represent T-prolymphocytic leukemia with TCL-1 gene rearrangement and diffuse marrow involvement. We also present an example of adult T-cell leukemia/lymphoma, which mimicked lymphoepithelioid variant of peripheral T-cell lymphoma also with diffuse marrow involvement. A subset of adult T-cell leukemia/lymphoma can closely mimic a variety of other more common T-cell neoplasms. Due to its extreme clinicopathologic heterogeneity, identification of adult T-cell leukemia/lymphoma requires a high level of suspicion based on patient demographic alone, which should prompt anti-human T-cell lymphotropic virus type 1/2 serology testing in all T-cell neoplasms developing in patients of appropriate demographic. Absence of high level of suspicion, adult T-cell leukemia/lymphoma is easily misclassified.

Biological and clinical significance of tryptophan-catabolizing enzymes in cutaneous T-cell lymphomas

Indoleamine 2,3-deoxygenase 1 (IDO1) induces immune tolerance in the tumor microenvironment (TME) and is recognized as a potential therapeutic target. We studied the expression of both IDO1 and the related tryptophan 2,3-dioxygenase (TDO) in several different subtypes of cutaneous T-cell lymphoma (CTCL), and evaluated the kynurenine (KYN) pathway in the local TME and in patient sera. Specimens from the total of 90 CTCL patients, including mycosis fungoides (MF, n = 37), lymphomatoid papulosis (LyP, n = 36), primary cutaneous anaplastic large cell lymphoma (pcALCL, n = 4), subcutaneous panniculitis-like T-cell lymphoma (SPTCL n = 13), and 10 patients with inflammatory lichen ruber planus (LRP), were analyzed by immunohistochemistry (IHC), immunofluorescence (IF), quantitative PCR, and/or liquid chromatography-tandem mass spectrometry (LC-MS/MS). Three CTCL cell lines also were studied. Expression of both IDO1 and TDO was upregulated in CTCL. In MF specimens and in the MF cell line MyLa2000, IDO1 expression exceeded that of TDO, whereas the opposite was true for LyP, ALCL, and corresponding Mac1/2A cell lines. The spectrum of IDO1-expressing cell types differed among CTCL subtypes and was reflected in the clinical behavior. In MF, SPTCL, and LyP, IDO1 was expressed by malignant cells and by CD33⁺ myeloid-derived suppressor cells, whereas in SPTCL CD163⁺ tumor-associated macrophages also expressed IDO1. Significantly elevated serum KYN/Trp ratios were found in patients with advanced stages of MF. Epacadostat, an IDO1 inhibitor, induced a clear decrease in KYN concentration in cell culture. These results show the importance of IDO1/TDO-induced immunosuppression in CTCL and emphasize its role as a new therapeutic target.

Characterization of the tumor microenvironment in primary cutaneous CD30-positive lymphoproliferative disorders: a predominance of CD163-positive M2 macrophages

BACKGROUND

The tumor microenvironment is essential for tumor survival, growth and progression. There are only a few studies on the tumor microenvironment in cutaneous CD30-positive lymphoproliferative disorders.

METHODS

We assessed the composition of the tumor microenvironment using immunohistochemistry studies in skin biopsies from cases diagnosed with lymphomatoid papulosis (LyP: 18 specimens), primary cutaneous anaplastic large-cell lymphoma (PC-ALCL: 8 specimens), and reactive diseases harboring CD30-positive cells (18 specimens).

RESULTS

The predominant cells present in LyP and PC-ALCL were CD163+ M2 macrophages (44.7%, 35%), followed by CD8+ tumor infiltrating lymphocytes (11%, 15%), FOXP3+ T-regulatory cells (9%, 4.5%) and programmed cell death 1(PD-1) + lymphocytes (2.2%, 6.8%). In contrast, CD30-positive reactive inflammatory and infectious disorders were characterized by higher numbers of CD123+ plasmacytoid dendritic cells (6.3%) when compared to LyP (1%), and PC-ALCL (1.1%).

CONCLUSIONS

Key differences exist between the microenvironment of CD30-positive lymphoproliferative disorders and reactive conditions harboring CD30-positive lymphocytes. The high number of tumor associated macrophages, and the close vicinity of these immune cells to the CD30-positive tumor cells might suggest that tumor associated macrophages have direct influence on tumorigenesis in LyP and ALCL. Therefore, modulation of M2 macrophages may represent a new therapeutic strategy in cutaneous CD30-positive lymphoproliferative disorders.

Peripheral T-cell and NK cell lymphoproliferative disorders: cell of origin, clinical and pathological implications

T-cell lymphoproliferative disorders are a heterogeneous group of neoplasms with distinct clinical-biological properties. The normal cellular counterpart of these processes has been postulated based on functional and immunophenotypic analyses. However, T lymphocytes have been proven to be remarkably capable of modulating their properties, adapting their function in relationship with multiple stimuli and to the microenvironment. This impressive plasticity is determined by the equilibrium among a pool of transcription factors and by DNA chromatin regulators. It is now proven that the acquisition of specific genomic defects leads to the enforcement/activation of distinct pathways, which ultimately alter the preferential activation of defined regulators, forcing the neoplastic cells to acquire features and phenotypes distant from their original fate. Thus, dissecting the landscape of the genetic defects and their functional consequences in T-cell neoplasms is critical not only to pinpoint the origin of these tumors but also to define innovative mechanisms to re-adjust an unbalanced state to which the tumor cells have become addicted and make them vulnerable to therapies and targetable by the immune system. In our review, we briefly describe the pathological and clinical aspects of the T-cell lymphoma subtypes as well as NK-cell lymphomas and then focus on the current understanding of their pathogenesis and the implications on diagnosis and treatment.

CD30 as a therapeutic target for lymphoma

Hodgkin's lymphoma (HL) and ALK(+) anaplastic large-cell lymphoma (ALCL) have become highly curable due to the success of modern regimens of chemotherapy and radiotherapy. However, up to one-third of the patients experience relapse or do not respond to first-line therapy, and half of them relapse again after secondary therapy with limited options for further treatment. In the last 15 years, monoclonal antibodies (mAbs) directed to surface receptors became a new and valuable therapeutic option in many hematologic malignancies. Due to its restricted expression on normal activated lymphocytes and its high expression on malignant cells, CD30 represents an attractive target molecule for HL and ALCL therapy. However, unconjugated CD30 mAbs have demonstrated a lack of objective clinical responses in patients with recurrent HL. CD30 exhibits complex signaling pathways, and binding of its natural ligand or anti-CD30 mAbs can induce apoptosis but may also promote proliferation and activation depending on the cellular context. Moreover, CD30 rapidly internalizes after crosslinking, which counteracts efficient recruitment of immunologic effectors but also provides the opportunity to transfer cytotoxic payloads coupled to CD30-specific mAbs into the tumor cells. Several tumor targeting approaches have been studied, including radio-immunoconjugates, immunotoxins, immunoRNases, immunokinases, and antibody drug conjugates (ADCs). In 2011, the ADC brentuximab-vedotin, consisting of the CD30-specific chimeric mAb cAC10 and the potent tubulin toxin monomethyl auristatin E, gained regulatory approval as a well tolerated and highly active drug in patients with refractory and relapsed HL and ALCL. SGN-35 is on the way to being incorporated in the standard management of CD30(+) lymphoma with significant therapeutic impact. This review gives a critical overview about anti-CD30 therapies with unconjugated, engineered, and conjugated mAbs and the therapeutic challenges of treatment of CD30(+) lymphoma.

Immune responses in a mouse model of vitiligo with spontaneous epidermal de- and repigmentation

To generate a mouse model of spontaneous epidermal depigmentation, parental h3TA2 mice, expressing both a human-derived, tyrosinase-reactive T-cell receptor on T cells and the matching HLA-A2 transgene, were crossed to keratin 14-promoter driven, stem cell factor transgenic (K14-SCF) mice with intra-epidermal melanocytes. In resulting Vitesse mice, spontaneous skin depigmentation precedes symmetrical and sharply demarcated patches of graying hair. Whereas the SCF transgene alone dictates a greater retinoic acid receptor-related orphan receptor gamma (RORγt)(+) T-cell compartment, these cells displayed markedly increased IL-17 expression within Vitesse mice. Similar to patient skin, regulatory T cells were less abundant compared with K14-SCF mice, with the exception of gradually appearing patches of repigmenting skin. The subtle repigmentation observed likely reflects resilient melanocytes that coexist with skin-infiltrating, melanocyte-reactive T cells. Similar repigmenting lesions were found in a different TCR transgenic model of vitiligo developed on an SCF transgenic background, supporting a role for SCF in repigmentation.

Epigenetics, autoimmunity and hematologic malignancies: a comprehensive review

The relationships between immunological dysfunction, loss of tolerance and hematologic malignancies have been a focus of attention in attempts to understand the appearance of a higher degree of autoimmune disease and lymphoma in children with congenital immunodeficiency. Although multiple hypotheses have been offered, it is clear that stochastic processes play an important role in the immunopathology of these issues. In particular, accumulating evidence is defining a role of epigenetic mechanisms as being critical in this continuous spectrum between autoimmunity and lymphoma. In this review, we focus attention predominantly on the relationships between T helper 17 (Th17) and T regulatory populations that alter local microenvironments and ultimately the expression or transcription factors involved in cell activation and differentiation. Abnormal expression in any of the molecules involved in Th17 and/or Treg development alter immune homeostasis and in genetically susceptible hosts may lead to the appearance of autoimmunity and/or lymphoma. These observations have clinical significance in explaining the discordance of autoimmunity in identical twins. They are also particularly important in the relationships between primary immune deficiency syndromes, immune dysregulation and an increased risk of lymphoma. Indeed, defining the factors that determine epigenetic alterations and their relationships to immune homeostasis will be a challenge greater or even equal to the human genome project.

Expression of the T-cell regulatory marker FOXP3 in primary cutaneous large B-cell lymphoma tumour cells

BACKGROUND

Primary cutaneous B-cell lymphomas (PCBCL) are subdivided into the aggressive form, primary cutaneous diffuse large B-cell lymphoma, leg type (PCLBCL, LT) and two subtypes of indolent behaviour (primary cutaneous follicle centre lymphoma and primary cutaneous marginal zone B-cell lymphoma). The difference in clinical behaviour can be explained by the tumour cell itself, or the lymphoma microenvironment including the antitumour immune response.

OBJECTIVES

To investigate the presence of regulatory T cells (Treg), CD4+CD25+FOXP3+, in the microenvironment of PCBCL in correlation with clinical outcome.

METHODS

Tumour specimens of 55 consecutive cases of PCBCL were blinded and analysed for FOXP3, CD4 and CD25 expression by immunohistochemistry. Confocal images were taken with a Leica SP5. Statistical analyses were performed to determine significance. The test was considered significant when P<0.05.

RESULTS

The CD4 and FOXP3 expression as well as the CD4/FOXP3 ratio were significantly increased in PCBCL of indolent behaviour in contrast to PCLBCL, LT (P=0.0002 for CD4, P<0.0001 for FOXP3 and P=0.0345 for FOXP3/CD4 ratio). CD25 expression did not differ in the three groups (P=0.9414). Within the group of patients with PCLBCL, LT we identified a subgroup with FOXP3+ tumour cells as demonstrated by CD20/FOXP3 double stainings. Patients with FOXP3+ PCLBCL, LT tumour cells showed a better prognosis on Kaplan-Meier analysis.

CONCLUSION

High numbers of Treg in the lymphoma microenvironment correlate with a better prognosis in PCBCL. In PCLBCL, LT the presence of FOXP3+ tumour cells is beneficial for prognosis suggesting that FOXP3 expression of PCLBCL, LT tumour cells might serve as a tumour suppressor.

The four types of Tregs in malignant lymphomas

Regulatory T cells (Tregs) are a specialized subpopulation of CD4⁺ T cells, which act to suppress the activation of other immune cells. Tregs represent important modulators for the interaction between lymphomas and host microenvironment. Lymphomas are a group of serious and frequently fatal malignant diseases of lymphocytes. Recent studies revealed that some lymphoma T cells might adopt a Treg profile. Assessment of Treg phenotypes and genotypes in patients may offer prediction of outcome in many types of lymphomas including diffuse large B-cell lymphoma, follicular lymphoma, cutaneous T cell lymphoma, and Hodgkin's lymphoma. Based on characterized roles of Tregs in lymphomas, we can categorize the various roles into four groups: (a) suppressor Tregs; (b) malignant Tregs; (c) direct tumor-killing Tregs; and (d) incompetent Tregs. The classification into four groups is significant in predicting prognosis and designing Tregs-based immunotherapies for treating lymphomas. In patients with lymphomas where Tregs serve either as suppressor Tregs or malignant Tregs, anti-tumor cytotoxicity is suppressed thus decreased numbers of Tregs are associated with a good prognosis. In contrast, in patients with lymphomas where Tregs serve as tumor-killing Tregs and incompetent Tregs, anti-tumor cytotoxicity is enhanced or anti-autoimmune Tregs activities are weakened thus increased numbers of Tregs are associated with a good prognosis and reduced numbers of Tregs are associated with a poor prognosis. However, the mechanisms underlying the various roles of Tregs in patients with lymphomas remain unknown. Therefore, further research is needed in this regard as well as the utility of Tregs as prognostic factors and therapy strategies in different lymphomas.

Correlation of the autoantibody response to the ALK oncoantigen in pediatric anaplastic lymphoma kinase-positive anaplastic large cell lymphoma with tumor dissemination and relapse risk

Anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL) constitutes an ideal model disease to study tumor-specific immune responses. All the tumor cells express oncogenic ALK resulting from a chromosomal translocation involved in lymphomagenesis. Although antibodies and T-cell responses to ALK have previously been detected in ALK-positive ALCL patients, their prognostic significance is unknown. We investigated a large cohort of uniformly treated ALK-positive pediatric ALCL patients to ascertain whether the titers of preexisting ALK autoantibodies correlated with clinical and histologic characteristics, tumor dissemination, and patient outcome. ALK autoantibodies were analyzed in pretherapeutic serum samples from 95 patients enrolled into 2 therapy studies between 1996 and 2007. ALK autoantibodies were detected in 87/95 patients. The titers inversely correlated with stage and amount of circulating tumor cells. High antibody titers correlated with significantly lower cumulative incidence of relapses (CI-R): titers > or = 1/60 750, n = 29, CI-R 11% +/- 6%; titers 1/2025-< 1/60 750, n = 39, CI-R 31% +/- 8%; and titers 0-< or = 1/750, n = 27, CI-R of 63% +/- 10% (P < .001). Our results provide the first clinical evidence that a robust preexisting immune response to an oncoantigen resulting from an oncogenic chromosomal translocation inhibits lymphoma dissemination and decreases the risk of relapse.

Cutaneous CD30 lymphoproliferative disorders and similar conditions: a clinical and pathologic prospective on a complex issue

We elaborate on the diagnosis of CD30 positive cutaneous lymphoproliferative conditions including the various clinical and pathological presentations, our understanding of its pathomechanisms and prognostic implications. The most common reactive conditions that can simulate CD30 lymphoproliferative conditions, including arthropod bite reactions, various viral infections, pityriasis lichenoides and lymphocytic papules in myelodysplastic syndrome, are discussed in detail.

Gene expression profiling of isolated tumour cells from anaplastic large cell lymphomas: insights into its cellular origin, pathogenesis and relation to Hodgkin lymphoma

Anaplastic large cell lymphoma (ALCL) is a main type of T-cell lymphomas and comprises three distinct entities: systemic anaplastic lymphoma kinase (ALK) positive, systemic ALK(-) and cutaneous ALK(-) ALCL (cALCL). Little is known about their pathogenesis and their cellular origin, and morphological and immunophenotypical overlap exists between ALK(-) ALCL and classical Hodgkin lymphoma (cHL). We conducted gene expression profiling of microdissected lymphoma cells of five ALK(+) and four ALK(-) systemic ALCL, seven cALCL and sixteen cHL, and of eight subsets of normal T and NK cells. The analysis supports a derivation of ALCL from activated T cells, but the lymphoma cells acquired a gene expression pattern hampering an assignment to a CD4(+), CD8(+) or CD30(+) T-cell origin. Indeed, ALCL display a down-modulation of many T-cell characteristic molecules. All ALCL types show significant expression of NFkappaB target genes and upregulation of genes involved in oncogenesis (e.g. EZH2). Surprisingly, few genes are differentially expressed between systemic and cALCL despite their different clinical behaviour, and between ALK(-) ALCL and cHL despite their different cellular origin. ALK(+) ALCL are characterized by expression of genes regulated by pathways constitutively activated by ALK. This study provides multiple novel insights into the molecular biology and pathogenesis of ALCL.

FOXP3+CD25- tumor cells with regulatory function in Sézary syndrome

Cutaneous T-cell lymphoma (CTCL) has been suggested by in vitro experiments to represent a malignant CD4+ T-cell proliferation with a regulatory T-cell (Treg) phenotype (CD4+CD25+FOXP3+). We investigated percentages of FOXP3+ and CD25+ cells in the blood of 15 Sézary, 14 mycosis fungoides (MF), and 10 psoriasis (Pso) patients and 20 normal healthy donors (NHDs). We found similar numbers of FOXP3+ cells in MF (10.4% of blood CD4+ cells) and Pso (11.1%) patients and NHDs (9.8%). In 8 of 15 (53%) Sézary patients, significantly reduced percentages of FOXP3+ cells were seen in blood (2.9%) and skin (10.4%). Interestingly, 6 of 15 (40%) Sézary patients showed significantly increased percentages of FOXP3+ cells (39.7% (blood), 20.3% (skin)); however, these cells did not express CD25. In these latter patients, clone-specific TCR-Vbeta-chain antibodies were used to demonstrate that these FOXP3+CD25- cells were monoclonal CTCL tumor cells. FOXP3+CD25- CTCL tumor cells showed a highly demethylated status of the foxp3 gene locus similar to Treg cells, and they were functionally able to suppress IL-2 mRNA induction in TCR-stimulated conventional T cells. Thus, FOXP3+CD25- CTCL tumor cells with functional features of Treg cells define a subgroup of Sézary patients who might carry a different prognosis and might require differential treatment.

FOXP3+ regulatory T cells as biomarkers in human malignancies

BACKGROUND

Regulatory T cells (Treg) expressing the FOXP3 forkhead transcription factor maintain immunological self-tolerance and can enable tumour cells to escape immunosurveillance.

OBJECTIVE

To provide an overview of studies using FOXP3 as a biomarker in human malignancies, particularly in the context of the antibodies used to detect FOXP3 protein expression, the cell populations selected for study, and the detection and scoring methodologies used.

METHODS

A personal selection of studies analysing FOXP3 as a marker of Treg cells in human malignancies are discussed.

RESULTS/CONCLUSION

FOXP3 is a useful marker that can be used in routine clinical practise to provide both diagnostic and prognostic information in human malignancies. However, the methods and reagents used to detect FOXP3 can have a significant effect on the robustness of experimental findings and conclusions.