The intracutaneous growth of murine lymphomas: epidermal invasion is characteristic of multiple tumor phenotypes

Sézary syndrome patient-derived models allow drug selection for personalized therapy

Patient-derived SS cells show highly heterogeneous drug responses.

We have developed a joint in vitro/in vivo platform to predict SS therapy response.

Current therapeutic approaches for Sézary syndrome (SS) do not achieve a significant improvement in long-term survival of patients, and they are mainly focused on reducing blood tumor burden to improve quality of life. Eradication of SS is hindered by its genetic and molecular heterogeneity. Determining effective and personalized treatments for SS is urgently needed. The present work compiles the current methods for SS patient–derived xenograft (PDX) generation and management to provide new perspectives on treatment for patients with SS. Mononuclear cells were recovered by Ficoll gradient separation from fresh peripheral blood of patients with SS (N = 11). A selected panel of 26 compounds that are inhibitors of the main signaling pathways driving SS pathogenesis, including NF-kB, MAPK, histone deacetylase, mammalian target of rapamycin, or JAK/STAT, was used for in vitro drug sensitivity testing. SS cell viability was evaluated by using the CellTiter-Glo_3D Cell Viability Assay and flow cytometry analysis. We validated one positive hit using SS patient–derived Sézary cells xenotransplanted (PDX) into NOD-SCID-γ mice. In vitro data indicated that primary malignant SS cells all display different sensitivities against specific pathway inhibitors. In vivo validation using SS PDX mostly reproduced the responses to the histone deacetylase inhibitor panobinostat that were observed in vitro. Our investigations revealed the possibility of using high-throughput in vitro testing followed by PDX in vivo validation for selective targeting of SS tumor cells in a patient-specific manner.

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.

A Microbiota-Dependent, STAT3-Driven Mouse Model of Cutaneous T-Cell Lymphoma

In recent years, much has been learned about the molecular genetics of cutaneous T-cell lymphomas. Fanok et al. (2018) translate knowledge from systematic genomic and transcriptomic analyses to develop a mouse model that tests the hypothesis that activated STAT3 in CD4⁺ T cells may be a driver of cutaneous T-cell lymphomas. The transgenic mouse that they developed exhibits clinical features of mycosis fungoides, as well as Sezary syndrome, two well-known entities in the cutaneous T-cell lymphoma spectrum. Furthermore, these authors show that TCR engagement and microbiota are required for development of the complete clinical phenotype. This mouse model, which develops progressive disease, provides a new tool to understand cutaneous T-cell lymphoma biology and to potentially test new therapies.

Simultaneous integrated boost with helical arc radiotherapy of total skin (HEARTS) to treat cutaneous manifestations of advanced, therapy-refractory cutaneous lymphoma and leukemia - dosimetry comparison of different regimens and clinical application

Background

Helical irradiation of the total skin (HITS) was modified as simultaneous integrated boost (SIB)-helical arc radiotherapy of total skin (HEARTS) technique and applied to an acute myeloid leukemia (AML) patient with disseminated leukemia cutis.

Methods

The original HITS plan was revised for different regimens, i.e. HEARTS, low-dose HEARTS and SIB-HEARTS. The uniformity index (UI), conformity index (CI), and dose of organs at risk (OARs) were used to evaluate the plans. Additionally, the SIB-HEART (21/15 Gy) was delivered to the total skin and chloromas.

Results

No significant differences were observed for the CI and UI between HITS and HEARTS regimens. Compared with HITS, the reduced mean doses to various bone marrows ranged from 17 to 88%. The mean OARs doses for the head, chest and abdomen of a patient with AML treated with SIB-HEARTS (21/15 Gy) were 2.1 to 21.9 Gy, 1.8 to 7.8 Gy and 1.7 to 3.3 Gy, respectively. No severe adverse effects were noted except for grade 4 leukocytopenia and thrombocytopenia.

Conclusion

HEARTS and different regimens reduced the dose to OARs and bone marrow while maintaining the uniformity and conformity. SIB-HEARTS deliveries different doses to the total skin and enlarged tumors simultaneously.

Trial registration

Retrospectively registered and approved by the Institutional Review Board of our hospital (FEMH-106151-C).

Epidermotropic cutaneous B-cell lymphoma mimicking mycosis fungoides

Cutaneous involvement by B-cell lymphoma is often secondary to systemic disease. Primary cutaneous B-cell lymphomas are less common, and patients generally have an excellent prognosis. We present a patient with cutaneous B-cell lymphoma with clinical and histologic features mimicking mycosis fungoides. Although the patient was initially misdiagnosed as having a T-cell lymphoma, immunophenotypic studies demonstrated that this was a B-cell lymphoma.

Evaluation of classic architectural criteria in non-mycosis fungoides cutaneous lymphomas

Ninety-seven cases of non-mycosis fungoides (non-MF) cutaneous lymphoma were evaluated employing published criteria for the categorization of B- and T-cell cutaneous malignancies. Included in the study were 77 primary and secondary cutaneous B-cell lymphomas, in which the diagnosis was supported by immunohistochemical studies identifying lineage. These cases were randomized with 20 cases of non-MF and T-cell lymphoma. Hematoxylin and eosin (H & E)-stained slides from each case were reviewed by at least two dermatopathologists, who were unaware of the previous diagnoses, and a judgment regarding histologic pattern was rendered. The histologic criteria employed emphasized architectural features. For B-cell patterns, these included the presence of dense perivascular, periappendageal and/or nodular collections of lymphocytes, centering in the deep dermis, and separation from the epidermis by a grenz zone. Employed criteria for cutaneous T-cell pattern included location restricted primarily to the upper dermis, interstitial pattern, the presence of epidermotropism, and the lack of a grenz zone. Three B-cell lymphomas were judged to have indeterminate patterns. Four of 74 (5.4%) of the remaining B-cell lymphomas were incorrectly categorized as T-cell lymphomas by architectural criteria. The most striking findings included epidermotropism in rare B-cell lymphomas. Three of the four miscategorized cases were large-cell lymphomas. A preference for B-cell pattern was also confirmed in non-MF T-cell lymphomas. We conclude that most B-cell lymphomas in the skin demonstrate a recognizable B-cell pattern, but rarely a pattern more reminiscent of T-cell lymphoma may be seen. This may occur more often with B-large-cell lymphomas. In addition, this study supports previous work indicating that many non-MF T-cell lymphomas show prominent architectural features typically ascribed to B-cell lymphomas. In summary, our findings support the impression that the vast majority of non-MF lymphomas show a B-cell pattern regardless of their lineage. As such, caution is indicated with regard to pattern interpretation.

Small, freshly arrived histiocytes in cutaneous and mucosal herpetic lesions

We report on the predominance of a special type of small histiocyte in the inflammatory infiltrate accompanying herpetic bullae. These histiocytes, which have previously been taken to be neutrophils, are freshly arrived cells with a hitherto unknown function. Until now, they have been found only in Sweet's syndrome and erythema nodosum where they form Miesscher's radial granulomas. Similar small histiocytes were found in half of those herpetic lesions with intact bullae, and in over two-thirds of ulcerated lesions in which these cells formed a palisade in the fibrinoid material covering the floor of the ulcerated vesicles. Small histiocytes, admixed with neutrophils, were in close proximity to virally infected keratinocytes. Immunohistochemical analysis confirmed their histiocytic nature. With the exception of ecthyma contagiosum (orf), similar small histiocytes were not found in other viral infections or in nonspecific ulcers of the skin. In cases of herpetic folliculitis, small histiocytes showed massive epidermotropism towards hair follicle epithelium. We conclude that cutaneous and oral herpetic infections represent yet another disease in which small, freshly arrived histiocytes occur. They may be involved in antigen presentation, or in killing of infected keratinocytes.

Malignant lymphoma and leukemia with prominent ulceration: clinicopathologic correlation of 33 cases

BACKGROUND

The clinical and pathologic findings in patients with malignant lymphomas who presented with prominent cutaneous ulcers are described.

OBJECTIVE

Our purpose was to determine the histologic findings, type, and prognosis of lymphomas with cutaneous ulcers.

METHODS

Thirty-three patients (20 with cutaneous T-cell lymphomas, 10 with other non-Hodgkin's lymphomas, and 3 with leukemia) were retrospectively studied.

RESULTS

All patients had a poor prognosis; 23 died within 9 months after the onset of the ulcers. Patients with non-Hodgkin's lymphoma had a worse prognosis, had a higher incidence of systemic involvement, and more often had ulcers as an initial manifestation of lymphoma than did the patients with cutaneous T-cell lymphoma. The histopathologic findings ranged from a nonspecific inflammatory infiltrate to ulcers with marked adjacent epidermal epidermotropism to ulcers with an angiocentric infiltrate.

CONCLUSION

A variety of lymphomas may cause cutaneous ulceration. Adequate sampling of these ulcers is necessary for diagnosis. The average life expectancy after ulcer formation is 21 months.

Primary B-cell lymphoma with histologic features of a T-cell neoplasm

A 58-year-old white man had dermatomyositis and primary cutaneous B-cell lymphoma. The cutaneous lymphoma was evidenced by a noduloulcerative disease of the lower extremities. Histologic results resembled a T-cell process with a diffuse, superficial infiltrate composed of small- and medium-sized lymphocytes with angioinvasion and epidermotropism. The infiltrate extended into the deep dermis and panniculus with scattered large lymphocytes and necrosis. With the help of gene-rearrangement analysis and immunophenotyping, the true B-cell lineage was discovered. The importance of gene-rearrangement analysis and immunophenotyping in the diagnosis of cutaneous lymphoma is emphasized.

Lichenoid tissue reaction induced by local transfer of Ia-reactive T-cell clones

Epidermal basal cell damage in lichenoid tissue reactions (LTR) is considered to be the result of immunologic injury. In this study, we propose that LTR may be caused by local activation of Ia-reactive T cells. We have established allo-Iak-reactive helper T-cell clones and examined their behavior after adoptive transfer. We show that local transfer of 3 allo-Iak-reactive helper T-cell clones with different cross-reactivities and functions in vitro can cause delayed type hypersensitivity (DTH) reactions in vivo with antigen specificities identical to those demonstrated in vitro. Clone SK.1, when injected into appropriate recipients, caused massive dermal infiltrates of neutrophils and mononuclear cells. The latter were attracted to the epidermis and induced LTR-like basal cell degeneration which peaked at 72 h. Appropriate recipients were those strains of mice whose spleen cells were able to stimulate SK.1 cells to proliferate in vitro. Two other clones, SK.2.18 and SK.2.16, evoked significant DTH responses in their appropriate recipients, but the massive cellular infiltrates induced by either clone never invaded the epidermis or produced an LTR. The degeneration of epidermal cells caused by SK.1 cells did not correlate with the tested functions of this clone in vitro. The finding that only 1 of the 3 allo-Ia-reactive helper T-cell clones induced epidermotropic cellular infiltrates indicates that the infiltrative pattern of leukocytes in skin may depend on the particular T-cell clone that is activated.