David A. Wada

B7-H1 (PD-L1, CD274) suppresses host immunity in T-cell lymphoproliferative disorders

Stromal elements present within the tumor microenvironment may suppress host immunity and promote the growth of malignant lymphocytes in B cell-derived non-Hodgkin lymphoma (NHL). In contrast, little is known about the microenvironments role in T cell-derived NHL. B7-H1 (PD-L1, CD274), a member of the B7 family of costimulatory/co-inhibitory ligands expressed by both malignant cells and stromal cells within the tumor microenvironment, has emerged as an important immune modulator capable of suppressing host immunity. Therefore, B7-H1 expression and function were analyzed in cutaneous and peripheral T-cell NHL. B7-H1 was expressed by tumor cells, monocytes, and monocyte-derived cells within the tumor microenvironment in T-cell NHL and was found to inhibit T-cell proliferation and promote the induction of FoxP3(+) regulatory T cells. Collectively, the data presented provide the first evidence implicating B7-H1 in the suppression of host immunity in T-cell lymphoproliferative disorders and suggest that the targeting of B7-H1 may represent a novel therapeutic approach.

Specificity of IRF4 translocations for primary cutaneous anaplastic large cell lymphoma: a multicenter study of 204 skin biopsies.

Current pathologic criteria cannot reliably distinguish cutaneous anaplastic large cell lymphoma from other CD30-positive T-cell lymphoproliferative disorders (lymphomatoid papulosis, systemic anaplastic large cell lymphoma with skin involvement, and transformed mycosis fungoides). We previously reported IRF4 (interferon regulatory factor-4) translocations in cutaneous anaplastic large cell lymphomas. Here, we investigated the clinical utility of detecting IRF4 translocations in skin biopsies. We performed fluorescence in situ hybridization (FISH) for IRF4 in 204 biopsies involved by T-cell lymphoproliferative disorders from 182 patients at three institutions. In all, 9 of 45 (20%) cutaneous anaplastic large cell lymphomas and 1 of 32 (3%) cases of lymphomatoid papulosis with informative results demonstrated an IRF4 translocation. Remaining informative cases were negative for a translocation (7 systemic anaplastic large cell lymphomas; 44 cases of mycosis fungoides/Sézary syndrome (13 transformed); 24 peripheral T-cell lymphomas, not otherwise specified; 12 CD4-positive small/medium-sized pleomorphic T-cell lymphomas; 5 extranodal NK/T-cell lymphomas, nasal type; 4 gamma-delta T-cell lymphomas; and 5 other uncommon T-cell lymphoproliferative disorders). Among all cutaneous T-cell lymphoproliferative disorders, FISH for IRF4 had a specificity and positive predictive value for cutaneous anaplastic large cell lymphoma of 99 and 90%, respectively (P=0.00002, Fishers exact test). Among anaplastic large cell lymphomas, lymphomatoid papulosis, and transformed mycosis fungoides, specificity and positive predictive value were 98 and 90%, respectively (P=0.005). FISH abnormalities other than translocations and IRF4 protein expression were seen in 13 and 65% of cases, respectively, but were nonspecific with regard to T-cell lymphoproliferative disorder subtype. Our findings support the clinical utility of FISH for IRF4 in the differential diagnosis of T-cell lymphoproliferative disorders in skin biopsies, with detection of a translocation favoring cutaneous anaplastic large cell lymphoma. Like all FISH studies, IRF4 testing must be interpreted in the context of morphology, phenotype, and clinical features.

Monocytes promote tumor cell survival in T-cell lymphoproliferative disorders and are impaired in their ability to differentiate into mature dendritic cells

A variety of nonmalignant cells present in the tumor microenvironment promotes tumorigenesis by stimulating tumor cell growth and metastasis or suppressing host immunity. The role of such stromal cells in T-cell lymphoproliferative disorders is incompletely understood. Monocyte-derived cells (MDCs), including professional antigen-presenting cells such as dendritic cells (DCs), play a central role in T-cell biology. Here, we provide evidence that monocytes promote the survival of malignant T cells and demonstrate that MDCs are abundant within the tumor microenvironment of T cell-derived lymphomas. Malignant T cells were observed to remain viable during in vitro culture with autologous monocytes, but cell death was significantly increased after monocyte depletion. Furthermore, monocytes prevent the induction of cell death in T-cell lymphoma lines in response to either serum starvation or doxorubicin, and promote the engraftment of these cells in nonobese diabetic/severe combined immunodeficient mice. Monocytes are actively recruited to the tumor microenvironment by CCL5 (RANTES), where their differentiation into mature DCs is impaired by tumor-derived interleukin-10. Collectively, the data presented demonstrate a previously undescribed role for monocytes in T-cell lymphoproliferative disorders.

Sweet syndrome: Clinical presentation, associations, and response to treatment in 77 patients

BACKGROUND Sweet syndrome is a neutrophilic dermatosis with cutaneous tender lesions that can be associated with malignancies, infections, systemic inflammatory disorders, and medications. Although numerous studies have described Sweet syndrome, few studies have systematically investigated Sweet syndrome. OBJECTIVE We sought to describe characteristics and treatments of patients with Sweet syndrome and evaluate clinical differences depending on the underlying cause. METHODS A retrospective study was conducted to identify patients with Sweet syndrome evaluated at Mayo Clinic from 1992 to 2010. RESULTS Of 77 patients with Sweet syndrome (mean age of onset 57 years), 43 (56%) were male. Eighteen patients (23%) reported a preceding infection. A total of 41 (53%) patients were classified as having classic Sweet syndrome, 27 (35%) patients had malignancy-associated Sweet syndrome, and in 9 (12%) patients drug-induced Sweet syndrome was considered. In all, 21 patients had a hematologic malignancy or myeloproliferative/myelodysplastic disorder, whereas 6 patients had solid tumors. The mean hemoglobin level, in both male and female patients (P < .0443 and P < .0035, respectively), was significantly lower in malignancy-associated versus classic and drug-induced Sweet syndrome. Systemic corticosteroids were the most frequently used treatment (70%). LIMITATIONS This is a retrospective study and represents patients from a single academic center. CONCLUSIONS Sweet syndrome is a distinctive disorder with certain clinical and histologic characteristics, which usually has a complete response to systemic corticosteroids. It is important to evaluate Sweet syndrome patients who have laboratory evidence of anemia for an underlying malignancy.

GATA-3 expression identifies a high-risk subset of PTCL, NOS with distinct molecular and clinical features.

The cell of origin and the tumor microenvironments role remain elusive for the most common peripheral T-cell lymphomas (PTCLs). As macrophages promote the growth and survival of malignant T cells and are abundant constituents of the tumor microenvironment, their functional polarization was examined in T-cell lymphoproliferative disorders. Cytokines that are abundant within the tumor microenvironment, particularly interleukin (IL)-10, were observed to promote alternative macrophage polarization. Macrophage polarization was signal transducer and activator of transcription 3 dependent and was impaired by the Janus kinase inhibitor ruxolitinib. In conventional T cells, the production of T helper (Th)2-associated cytokines and IL-10, both of which promote alternative macrophage polarization, is regulated by the T-cell transcription factor GATA-binding protein 3 (GATA-3). Therefore, its role in the T-cell lymphomas was examined. GATA-3 expression was observed in 45% of PTCLs, not otherwise specified (PTCL, NOS) and was associated with distinct molecular features, including the production of Th2-associated cytokines. In addition, GATA-3 expression identified a subset of PTCL, NOS with distinct clinical features, including inferior progression-free and overall survival. Collectively, these data suggest that further understanding the cell of origin and lymphocyte ontogeny among the T-cell lymphomas may improve our understanding of the tumor microenvironments pathogenic role in these aggressive lymphomas.

Clinical, histopathologic, and immunophenotypic features of lymphomatoid papulosis with CD8 predominance in 14 pediatric patients.

BACKGROUND Lymphomatoid papulosis (LyP) is a cyclic papulonodular eruption that is clinically benign and histologically malignant. Association with hematologic neoplasias has been reported in 5% to 20% of all cases. OBJECTIVE We sought to review the clinical and histopathologic features of LyP in pediatric patients. METHODS We searched for the records of all patients with a clinical and histopathologic diagnosis of LyP seen at our clinic from January 1991 through April 2008. The cases of pediatric patients (aged < 20 years) were reviewed in detail. RESULTS Of 123 patients with LyP identified, 14 (11%) were in the pediatric age group. Most were male (64%); mean age of onset was 12 years. Type A LyP was identified in 12 patients, one patient had type B, and none had type C (type not determined in one case). Ten cases showed CD8 predominance by immunohistochemistry. T-cell intracytoplasmic antigen staining was positive in 3 cases of CD8(+) LyP type A and the one case of LyP type B. Lesional T-cell receptor gene rearrangement studies were negative in 9 of 10 patients with LyP type A. The average follow-up time was 5.5 years. Lesions improved with treatment in most cases, and none of the cases were associated with hematologic malignancies. LIMITATIONS This was a retrospective review. CONCLUSIONS Among our pediatric patients, we noted a predominance of CD8(+) LyP, which does not seem to have an aggressive course. Further longitudinal studies are necessary to evaluate prognostic differences between CD4(+) and CD8(+) LyP and their biological significance.

Cutaneous small-vessel vasculitis associated with solid organ malignancies: The Mayo Clinic experience, 1996 to 2009

BACKGROUND Although rare, cutaneous small-vessel vasculitis (CSVV) secondary to solid organ malignancy has been documented. OBJECTIVE We sought to better understand the frequency, clinical course, therapeutic response, and outcome of CSVV associated with solid organ malignancy. METHODS We conducted a retrospective chart review of patients seen between 1996 and 2009 with diagnoses of biopsy-proven cutaneous leukocytoclastic vasculitis and solid organ malignancy separated by less than 12 months. RESULTS Of 17 patients (mean age, 66.5 years), 10 patients (59%) were male. CSVV occurred before (3 patients; 18%), concurrent with (3 patients; 18%), and after (11 patients; 65%) diagnosis of solid organ malignancy. The most common solid organ malignancy was of the lung (n = 4; 24%). Other associated cancers were breast (n = 3); prostate (n = 2); colon (n = 2); renal (n = 2); thyroid (n = 1); bladder (n = 1); gallbladder (n = 1); and peritoneal (n = 1). Three patients had cutaneous vasculitis in association with malignancy recurrence despite having no cutaneous vasculitis associated with their primary malignancy. Vasculitis remission with use of immunosuppressive agents alone occurred in 9 patients (53%). Eleven patients (65%) were alive at last follow-up (mean follow-up duration, 27 months). LIMITATIONS This was a retrospective study with a relatively small number of patients. CONCLUSION Solid organ malignancy should be considered as a possible cause of CSVV of unknown origin. In contrast to previous reports, our patients were more likely to respond to immunosuppressive therapies without treatment of the associated malignancy and to be alive at last follow-up.

Programmed death 1 is expressed in cutaneous infiltrates of mycosis fungoides and Sézary syndrome

Expression of PD-1 (receptor Programmed Death 1, CD279) in some peripheral T-cell lymphomas has recently been demonstrated. Because antibody-based therapies have improved outcomes in non-Hodgkin lymphoma, and antibodies targeting PD-1 are in clinical development, expression of this molecule in cutaneous T-cell lymphoma may be of therapeutic interest. There are no studies to date specifically addressing the frequency and extent of PD-1 expression in mycosis fungoides or Sezary syndrome. We thus characterized PD-1 expression in mycosis fungoides and Sezary syndrome by immunohistochemistry on lesion skin biopsies and by flow cytometry on peripheral blood tumor cells. Fifteen of 30 cases of mycosis fungoides and 8 of 11 cases of Sezary syndrome were positive for PD-1 by immunohistochemistry. Circulating tumor cells from five of the immunohistochemistry-positive cases of Sezary syndrome were evaluated by flow cytometry and also found to be positive. These data indicate that a substantial proportion of patients with mycosis fungoides and Sezary syndrome are positive for PD-1. This result warrants further investigation of PD-1 as a potential therapeutic target.

Melanocytes in nonlesional sun-exposed skin: A multicenter comparative study

BACKGROUND There are limited data regarding melanocyte density and distribution on sun-exposed skin of the head and neck, in particular, comparing morphology (hematoxylin-eosin [H&E] staining) and immunohistochemistry (Melan-A staining) on formalin-fixed tissue. Furthermore, comparisons of melanocyte density between distinct geographic populations have not been made using these methods. This information would be useful for physicians who use histologic criteria to diagnose and treat lentigo maligna. OBJECTIVE We aimed to characterize the density and distribution of melanocytes using Melan-A and H&E stains on nonlesional sun-exposed skin of the face and neck, and compare the results between patients seen in Florida and Minnesota. We also aimed to quantify the presence and extent of features considered characteristic of melanoma in these noncancerous specimens of sun-damaged skin. The overall goal was to be able to provide this information to physicians who perform histopathologic interpretations of skin biopsy specimens to potentially prevent the overdiagnosis of melanoma. METHODS In all, 100 patients undergoing Mohs micrographic and reconstructive surgery for basal cell and squamous cell carcinoma were enrolled, 50 each at the two sites. Permanent tissue sections were prepared from sun-exposed skin without clinical lesions. Melanocyte density and distribution were quantified. RESULTS The overall median and 90th percentile, respectively, of melanocytes per high-power field was 9 and 14 on the H&E-stained sections and 11 and 19 on the Melan-A-stained sections. The means were 9.3 and 12.0, respectively (P < .001). There was evidence that melanocyte densities were higher in patients in Florida than in Minnesota, at least using H&E staining. There was evidence of lower melanocyte densities with increasing age, more so for Melan-A than H&E staining, and higher densities in men using Melan-A. Confluence was noted in 24% of cases using H&E and 45% using Melan-A. More than two thirds of these were classified as having mild confluence, whereas the others demonstrated higher amounts of confluence (3-8 melanocytes). Only 37 patients had a follicle present; of these, 7 patients had follicular extension although this did not extend beyond 1 mm in depth. Cytologic atypia was noted in 19 of the 100 patients; pagetoid spread was found in 3. LIMITATIONS This was a selected population of patients; results may not be generalizable to the wider population. Variables such as contours of the epidermis (rete density), density of hair follicles, and epidermal thickness may affect the reproducibility of the results. Melanomas were not included for comparison. CONCLUSION Relatively high melanocyte density, mild to moderate confluence of melanocytes, focal pagetosis, superficial follicular extension (<1.0 mm), and mild or moderate cytologic atypia may be observed in the absence of a melanocytic neoplasm. It is important for physicians to be aware of these findings so that such features are interpreted appropriately when making a histologic assessment that may ultimately influence therapy and outcome.

Paucity of Intraepidermal FoxP3-Positive T Cells in Cutaneous T-Cell Lymphoma in Contrast With Spongiotic and Lichenoid Dermatitis

Background: FoxP3 is the most specific available marker for regulatory T cells (Tregs). Tumor‐associated FoxP3‐positive Tregs have been identified in various neoplasms, including cutaneous T‐cell lymphoma (CTCL). FoxP3 expression in CTCL varies across groups; few studies have compared CTCL with inflammatory conditions.