Target role of Langerhans cells in mycosis fungoides: transmission and immuno-electron microscopic studies

Mycosis Fungoides and Sézary Syndrome: Microenvironment and Cancer Progression

Mycosis fungoides and Sézary syndrome are epidermotropic cutaneous lymphomas, and both of them are rare diseases. Mycosis fungoides is the most frequent primary cutaneous lymphoma. In about 25% of patients with mycosis fungoides, the disease may progress to higher stages. The pathogenesis and risk factors of progression in mycosis fungoides and Sézary syndrome are not yet fully understood. Previous works have investigated inter- and intrapatient tumor cell heterogeneity. Here, we overview the role of the tumor microenvironment of mycosis fungoides and Sézary syndrome by describing its key components and functions. Emphasis is put on the role of the microenvironment in promoting tumor growth or antitumor immune response, as well as possible therapeutic targets. We focus on recent advances in the field and point out treatment-related alterations of the microenvironment. Deciphering the tumor microenvironment may help to develop strategies that lead to long-term disease control and cure.

Role of langerin-positive and CD83+ cells in the pathogenesis of mycosis fungoides

Dendritic cells regulate the balance between the immune response and immunotolerance; their role in the pathogenesis of skin lymphomas is underexplored. Goal. To study the number of populations of CD83+ and langerin positive cells in the skin of patients suffering from mycosis fungoides and small plaque parapsoriasis. Materials and methods. The authors determined the content of langerin-positive and CD83+ cells by means of immunohistochemistry of skin biopsy samples taken from patients suffering from mycosis fungoides (17 subjects) and small plaque parapsoriasis (6 subjects). The control group comprised 16 healthy people. Results. The study revealed that langerin positive and CD83+ dendritic cells prevailed in patients suffering from mycosis fungoides as compared to patients with small plaque parapsoriasis and healthy subjects. The share of immature dendritic cells grows in patients with parapsoriasis and mycosis fungoides. Conclusion. The statistically reliable difference between the amount of langerin positive and CD83+ dendritic cells as well as immature to mature dendritic cells ratio in case of mycosis fungoides vs. small plaque parapsoriasis can serve as an additional diagnostics criterion for these diseases.

Increased CCL18 expression in patients with cutaneous T-cell lymphoma: association with disease severity and prognosis

BACKGROUND

CC chemokine ligand (CCL) 18 is expressed by monocytes and dendritic cells (DCs), and has potent chemotactic activity for T cells, B cells and DCs. CCL18 expression is up-regulated in lesional skin of atopic dermatitis and bullous pemphigoid, suggesting its important roles in the development of these skin diseases.

OBJECTIVE

To investigate roles of CCL18 in cutaneous T-cell lymphoma (CTCL).

METHODS

The CCL18 messenger RNA (mRNA) expression in CTCL skin (n = 21) and in normal skin (n = 7) was examined by quantitative RT-PCR. CCL18 expression was also examined by immunohistochemistry. Serum CCL18 levels were measured in 38 patients with CTCL and 20 healthy controls by enzyme-linked immunosorbent assay. We also analysed correlation between serum CCL18 levels and other clinical and laboratory data.

RESULTS

The CTCL lesional skin contained higher levels of CCL18 mRNA than normal skin. CCL18 was expressed by dermal macrophages and DCs in CTCL skin. Serum CCL18 levels in patients with CTCL were significantly higher than those of healthy controls and correlated with types of skin lesions. They also significantly correlated with modified severity-weighted assessment scores, serum sIL-2R, LDH, IL-4, IL-10, IL-31, CCL17 and CCL26 levels. Patients with high serum levels of CCL18 showed significantly poor prognosis compared with those with low CCL18 levels.

CONCLUSION

CCL18 mRNA is up-regulated in CTCL lesional skin, and serum CCL18 levels are significantly increased and correlated with the severity of CTCL. These results suggest that CCL18 may be associated with the development of CTCL.

Improved generation of anti-tumor immunity by antigen dose limitation

Background

The malignant cells of cutaneous T cell lymphoma (CTCL) display immunogenic peptides derived from the clonal T cell receptor (TCR) providing an attractive model for refinement of anti-tumor immunization methodology. To produce a clinically meaningful anti-tumor response, induction of cytotoxic anti-CTCL cells must be maximized while suppressive T regulatory cells (Treg) should be minimized. We have demonstrated that engulfment of apoptotic CTCL cells by dendritic cells (DC) can lead to either CD8 anti-CTCL responses or immunosuppressive Treg induction. Treg generation is favored when the number of apoptotic cells available for ingestion is high.

Methods

In this study, we sought to determine whether the balance between immunity and immunosuppression could be shifted towards a CD8 anti-CTCL response by lowering the ratio of apoptotic CTCL cells available for DC ingestion. CTCL cell apoptosis was produced by engagement of the TCR by anti-CD3 antibody affixed to magnetic beads.

Results

The physical perturbation inherent in passage through a separation column induced monocytes to differentiate into DC, demonstrated by increased expression of class II and CD86 and decreased expression of the monocyte marker CD14. The immature DC internalized and processed apoptotic CTCL cells and could potentially present the tumor-derived peptides in the context of MHC class I and II. As the number of apoptotic cells increased, there was a dose-dependent increase in the expression of Treg markers CTLA-4, CD25, and FoxP3, with a ratio of apoptotic cell/DC loading of > 10:1 corresponding to the greatest Treg induction. These inducible phenotypic Treg also functionally inhibited CD8-mediated perforin expression in vitro. At lower levels of apoptotic cell/DC loading of < 5:1, there was an expansion of the CD8 T cell compartment with increased perforin expression and increased CTCL cell death, indicating anti-tumor activity.

Conclusion

These findings demonstrate that the ratio of apoptotic cells supplied to DC is an important determinant of whether CD8 anti-tumor immunity or immunosuppression is generated.

Cutaneous T-cell lymphoma: malignant proliferation of T-regulatory cells

Studies in an in vitro model of cutaneous T-cell lymphoma (CTCL) demonstrated that CTCL cell proliferation is stimulated by direct contact with autologous, immature dendritic cells (DCs), suggesting that CD4(+) CTCL cell division is driven by antigens presented by DC major histocompatibility complex (MHC) class 2. We now report that the T-cell receptor (TCR) of the CD4(+) CTCL cells is triggered after interaction with DCs loaded with apoptotic CTCL cells, as shown by reduced membrane expression of CD3 and the TCR, up-regulation of cytotoxic T lymphocyte antigen-4 (CTLA-4), and calcium mobilization. CTCL cells adopt a T-regulatory (Treg) phenotype expressing CD25/CTLA-4 and FoxP3 and secreting interleukin-10 (IL-10) and transforming growth factor-beta (TGF-beta). Treg CTCL cells suppress normal T-cell antigen-driven secretion of IL-2 and interferon-gamma (IFN-gamma). Blocking DC MHC class 2 expression or transport inhibited CTCL cell adoption of a Treg phenotype. Allogeneic CTCL cells or normal CD4 T cells served as sources of apoptotic material for CTCL cell conversion to a Treg phenotype. Conversion of CTCL cells to Treg cells may explain the anergic, immunosuppressive nature of the malignancy.

Transimmunization, a novel approach for tumor immunotherapy

This review describes our experience with the development of a novel form of immunotherapy that may represent the first practical and effective means of performing tumor-loaded dendritic cell (DC) immunotherapy. We have modified the highly successful extracorporeal photopheresis (ECP) treatment that has been used in the therapy of cutaneous T cell lymphoma (CTCL). autoimmune disease, transplantation rejection episodes and graft-versus-host disease to enhance its efficacy by the addition of an overnight incubation period. This adaption of ECP is termed "transimmunization (TI)" since the new therapy permits transfer of tumor antigens that have been previously poorly recognized to potent antigen presenting cells where the tumor epitopes can be displayed in the full context of major histocompatibility, co-stimulatory and adhesion molecules. The TI modification of ECP is a practical and safe means of rapidly inducing DC differentiation from peripheral blood monocytes in the presence of apoptotic tumor cells. Uptake of the apoptotic CTCL cells by the immature DC, in the presence of inflammatory cytokines, further drives their maturation into potent antigen presenting cells. Reinfusion of these tumor-loaded DC, that have access to the full spectrum of tumor antigens, has the potential to invoke an anti-tumor immune response in the recipient. Standard ECP has been a very useful form of immunotherapy and a modification of this approach that can enhance its ellicacy and utility should broaden its application to a larger variety of disorders including potentially the treatment of solid tumors and the modulation of the immune response in graft-versus-leukemia and graft-versus-host transplantation regimens. An understanding of the mechanism of ECP and TI will provide the physician with the ability to more finely tune the desired immune response and thereby, provide an enhanced immunotherapy for malignancy and other disorders of immunocompetence.

The growth of cutaneous T-cell lymphoma is stimulated by immature dendritic cells

In the initial stage of cutaneous T-cell lymphoma (CTCL), proliferating CTCL cells are concentrated in the epidermis in close association with an immature dendritic cell (DC), the Langerhans cell. Because long-term in vitro culture of CTCL cells has proven difficult, the in vivo association with the major antigen-presenting cell (APC) of the epidermis has been postulated to play a role in directly stimulating the clonal T-cell proliferation. We report that CTCL cells can be reproducibly grown in culture for 3 months when cocultured with immature DCs. CTCL cells retain the phenotype and genotype of the initial malignant clone, whereas the APCs are a mixture of immature and mature DCs. CTCL cell and DC survival was dependent on direct membrane contact. Growth was inhibited by antibodies that bound to the T-cell receptor (TCR) or interfered with the interaction of CD40 with its ligand on the CTCL cell. Addition of antibody to CD3 or the clonotypic TCR caused rapid CTCL cell apoptosis followed by engulfment by avidly phagocytic immature DCs and subsequent DC maturation. The opportunity to study CTCL cells and immature DCs for prolonged periods will facilitate studies of tumor cell biology and will allow investigation of the intriguing hypothesis that CTCL cell growth is driven through TCR recognition of class II–presented self-peptides. In addition, the culture of CTCL cells will permit evaluation of therapies in vitro before clinical intervention, thereby improving safety and efficacy.

The growth of cutaneous T-cell lymphoma is stimulated by immature dendritic cells

In the initial stage of cutaneous T-cell lymphoma (CTCL), proliferating CTCL cells are concentrated in the epidermis in close association with an immature dendritic cell (DC), the Langerhans cell. Because long-term in vitro culture of CTCL cells has proven difficult, the in vivo association with the major antigen-presenting cell (APC) of the epidermis has been postulated to play a role in directly stimulating the clonal T-cell proliferation. We report that CTCL cells can be reproducibly grown in culture for 3 months when cocultured with immature DCs. CTCL cells retain the phenotype and genotype of the initial malignant clone, whereas the APCs are a mixture of immature and mature DCs. CTCL cell and DC survival was dependent on direct membrane contact. Growth was inhibited by antibodies that bound to the T-cell receptor (TCR) or interfered with the interaction of CD40 with its ligand on the CTCL cell. Addition of antibody to CD3 or the clonotypic TCR caused rapid CTCL cell apoptosis followed by engulfment by avidly phagocytic immature DCs and subsequent DC maturation. The opportunity to study CTCL cells and immature DCs for prolonged periods will facilitate studies of tumor cell biology and will allow investigation of the intriguing hypothesis that CTCL cell growth is driven through TCR recognition of class II–presented self-peptides. In addition, the culture of CTCL cells will permit evaluation of therapies in vitro before clinical intervention, thereby improving safety and efficacy.

Diversity of immunobiological functions of T-cell lines established from patients with adult T-cell leukaemia

In order to understand the variety of HTLV-1-associated cutaneous diseases, we studied the cytological profile of HTLV-1-infected T-cell lines established from patients with adult T-cell leukaemia (ATL). Among four CD4+ cell lines, termed 16T(-), 35T(-), MH-1, and KS-2, the 16T(-) cells secreted elevated quantities of IL-4, IL-6 and IFN-gamma and expressed mRNA for each cytokine in the absence of exogenous stimulation. The 35T(-) cells secreted IL-6 and a small amount of IFN-gamma, but not IL-4. The MH-1 and KS-2 cells secreted only IL-6 in the absence of stimulation. In response to stimulation with phorbol-12-myristate-13 acetate (PMA), the 16T(-) cells produced more IL-4 and IFN-gamma, whereas the 35T(-) and MH-1 cells exhibited increased secretion of IFN-gamma, but still no IL-4 or IL-4 mRNA production. Although neither IL-4 nor IFN-gamma were found in the culture supernatant of KS-2 cells, the production of IL-4 mRNA was detected by RT-PCR. Culture supernatants from the 16T(-) and 35T(-) cells induced the expression of intercellular adhesion molecule-1 (ICAM-1) and HLA-DR by cultured keratinocytes. This response was inhibited by pretreatment of the supernatant with anti-IFN-gamma antibodies. These results indicate that some HTLV-1-infected T-cell lines constitutively secrete various cytokines, including biologically active IFN-gamma. The diversity of immunobiological functions of the T-cell lines may be related to the variety of clinical features present in ATL patients.

Induction of intercellular adhesion molecule-1 and adherence of HTLV-1-infected T-cells to cultured keratinocytes

Cutaneous lesions of T-cell proliferative disorders are characterized by epidermotropic infiltration of the neoplastic cells and expression of intercellular adhesion molecule-1 (ICAM-1) and HLA-DR by lesional keratinocytes. Using cloned HTLV-1-infected T-cells obtained from patients with adult T-cell leukemia (ATL), we have studied immunobiological activities of cytokines released from the T-cell lines and their ability to adhere to cultured keratinocytes. Three out of the five CD-4-positive, HTLV-1-infected T-cell clones secreted both IFN-gamma and IL-4, similar to murine Th0 clones. The other two clones did not produce such cytokines. ICAM-1 and HLA-DR molecules were induced on cultured normal human keratinocytes and organ-cultured skin specimens by co-cultivation with IFN-gamma-producing T-cell clones or their culture supernatants. Induction of both molecules was markedly inhibited by pretreatment of the supernatants with excess amounts of anti-IFN-gamma monoclonal antibody. The number of cells adherent to the normal cultured keratinocytes was greater in the IFN-gamma-producing clones than in the non-producing ones. These data suggest that some HTLV-1-infected clones produce cytokines, including IFN-gamma, which in turn induce ICAM-1 on keratinocytes, thereby enhancing the ability of the T-cell clones to adhere to the keratinocytes.

Oral manifestations of cutaneous T cell lymphoma

Oral manifestations of cutaneous T cell lymphoma (CTCL) have received little attention in the dermatologic literature. The authors report two patients with lingual lesions. The histologic features are similar to those of the glabrous skin. A review of the 22 previously reported cases indicate a shortened survival. A retrospective review of 82 patients with CTCL treated at the authors' medical center identified only three with oral involvement. Radiation therapy offers effective palliation for these lesions.

Epidermal Langerhans' cell densities influence survival in mycosis fungoides and Sézary syndrome

Because Langerhans' cells (LC) (CD1a-positive epidermal cells) have been discussed to be involved in the pathogenesis of mycosis fungoides and Sézary syndrome, the authors examined the influence of densities of Langerhans' cells and, concurrently, of other phenotypes retrospectively on survival of 35 patients. Cell densities were assessed on cryostat sections (alkaline phosphatase antialkaline phosphatase-technique) of the respective diagnostic biopsy specimens. Additionally, two clinical parameters (age, stage of disease) were evaluated. CD1a-positive epidermal cells were demonstrated to be the only cell population being significantly associated (P = 0.011) with survival. Death resulting from mycosis fungoides and Sézary syndrome was significantly (P = 0.003) less frequent in patients with epidermal CD1a-positive cell densities higher than 90 cells/mm2 (optimal break point) as compared with patients with lower numbers. These results suggest that Langerhans' cells have a significant impact on prognosis of patients with mycosis fungoides and Sézary syndrome. They play an important role in the host defense mechanisms against these lymphomas rather than to favor their progression as proposed recently.

Langerhans cells in oral epithelium of chronically inflamed human gingivae

This study describes the histopathological features and the distribution of oral epithelial Langerhans cells in 19 gingival biopsies originating from an adult Tanzanian population characterized by very poor oral hygiene and severe gingival inflammation. Light-microscopically, all biopsies contained often large inflammatory connective tissue infiltrates, 6 of which predominantly contained plasma cells while the rest were dominated by lymphocytes. Seven specimens contained peculiar accumulations of round lymphoid and dendritic cells in the lower cell layers of the oral epithelium. These phenomena have not previously been demonstrated in human gingiva and deserve further attention in studies on the pathogenesis of periodontal diseases. Immuno-histochemical staining with OKT6, OKT4 and OKT8 antibodies showed markedly increased numbers of OKT6-positive cells in 7 specimens and clusters of OKT4- and OKT8-positive cells in the oral epithelium of 4 specimens. High numbers of OKT6-positive cells were not related to the presence of intra-epithelial, non-keratinocyte infiltrates or large connective tissue infiltrates. The variable numbers of oral epithelial Langerhans cells may therefore result from different bacterial antigens elucidating different responses or, alternatively, reflect different responses to similar plaque antigens penetrating the surface of the oral epithelium.

Ultrastructural characteristics of the contact zones between Langerhans cells and lymphocytes

The present work was carried out to look for the ultrastructural substrate of the contact zones between Langerhans cells and lymphocytes. A high resolution electron microscopic analysis of the contact zones between Langerhans cells and lymphocytes was performed. The material used for this study was obtained from experimental contact dermatitis in mice, and human cervical squamous carcinoma and mycosis fungoides. Three types of cell-cell binding were found. Type I is a junction-like structure characterized by the presence of intercellular bridges. It is suggested that this contact might represent a fixation mechanism between the two cells. Type II is characterized by a glycocalyx-glycocalyx continuity. An immunological function--recognition and antigen presentation--is proposed for this type of contact. Type III is a septilaminar tight contact area which seems to be a gap junction. It is suggested that all these types of physical contact might be the morphological expression of interaction between antigen presenting cells and lymphocytes.

Expression of OKM5 antigen on epidermal cells in mycosis fungoides plaque stage

To characterize and quantitate potential antigen-presenting cell subsets in the epidermis of patients with cutaneous T-cell lymphoma, epidermal cells in suspension were obtained from involved and uninvolved skin. Involved epidermis contained increased numbers of OKT6+HLA-DR+ Langerhans cells and a variable number of OKM5+ epidermal cells (ECs) in all mycosis fungoides (MF) patients tested (N = 14). The OKM5+ EC population from involved epidermis of MF patients were heterogeneous and comprised both OKM5+HLe1- keratinocytes and OKM5+HLe1+ leukocytes. Uninvolved epidermis, in 6 of 14 patients with MF, contained a small number of OKM5+ leukocytes; however, no OKM5+ keratinocytes were detected. Neither OKM5+ leukocytes nor OKM5+ keratinocytes were detected in the epidermis obtained from healthy controls. The increased number of potential antigen-presenting cells, that is, OKT6+HLA-DR+ Langerhans cells and OKM5+HLA-DR+ monocytic leukocytes, in the epidermis of patients with MF may be important for the activation of abnormal T cells contained within the epidermis of these patients. Such activated T cells may release gamma-interferon and induce expression of both HLA-DR and OKM5 antigens on keratinocytes. OKM5+ keratinocytes are present in the epidermis of patients with MF, but not in normal skin, and may thus play a role in the pathogenetic mechanisms of mycosis fungoides by recruitment of immunocompetent cells to the epidermis.

Role of epidermal Langerhans cells in viral infections

Langerhans cells function as highly potent antigen-presenting cells in the epidermis. In the last few years, their role in viral infections has been studied in various experimental systems. They have been shown to be involved in the pathogenesis of a number of infections of viral origin. These include vaccinia virus, human papilloma virus, herpes simplex virus, foot and mouth disease virus and human retrovirus infections. Studies on the effect of various factors, that are known to modulate the activity and density of Langerhans cell in the epidermis, may lead in the future to the development of new strategies aimed at inhibiting virus infections or even eradicating latent infection.

Immunopathologic study of lichenoid skin diseases: correlation between HLA-DR-positive keratinocytes or Langerhans cells and epidermotropic T cells

Skin biopsy specimens from 24 patients with different lichenoid skin diseases that had been proved histologically were studied immunohistologically. Marked differences were noted in the number of OKT6+/S100+ Langerhans cells within the epidermis and dermis in the lesional skin between lichen planus (and its related disease) and lupus erythematosus; in the former these cells were increased in number; in the latter they were decreased in number compared with those in uninvolved perilesional skin. Human lymphocyte antigen (HLA)-DR expression on keratinocytes was observed not only in lichenoid skin diseases but also in control cases without epidermal involvement. In the two cases of systemic lupus erythematosus, the uninvolved perilesional skin also show weak and focal HLA-DR reactivity in the basal layer. HLA-DR+ keratinocytes could play an important role at least in the perpetuation of epidermal cell damage mediated by T cells.

Electron microscopic and immunolabeling studies of the lesional and normal skin of patients with mycosis fungoides treated by total body electron beam irradiation

Biopsy specimens were taken from lesional and normal skin of nine patients with mycosis fungoides before and after total body electron beam therapy. By electron microscopy, lesional skin had one and one-half to ten times as many epidermal Langerhans cells and indeterminate cells as did the normal skin. In successfully treated lesional skin 1 month after the end of electron beam therapy, the density of epidermal Langerhans cells and indeterminate cells had decreased markedly. In incompletely resolved lesions, Langerhans cells and indeterminate cells were still at pretreatment levels. Epidermal T6 and Ia antigens showed the same pattern of response. Epidermal cell suspensions from lesional and normal skin before and after electron beam therapy were assayed for epidermal thymocyte activating factor. The values of production of this factor did not correlate with the source of the epidermal cells, response to therapy, or the patient's disease course. Skin lesions resembling xerosis and parapsoriasis and histologically lacking the criteria for mycosis fungoides appeared during clinical remissions. These nonspecific skin lesions had densities of epidermal Langerhans cells, indeterminate cells, and T6-positive and Ia-positive cells comparable to levels found in pretreatment lesional skin.

Immunohistochemical study of epidermal Langerhans cells and dermal dendritic cells in benign and malignant skin lesions characterized by a dermal lymphoid infiltrate consisting either of B-cells or T-cells

Skin biopsies from 43 patients with a rather dense dermal lymphoid infiltrate of either inflammatory or neoplastic nature have been investigated. We studied the number, distribution and immunophenotype of epidermal Langerhans cells and dermal dendritic cells. As previously reported, differences in epidermal Langerhans cell and dermal dendritic cell numbers between skin biopsies with a B-cell infiltrate and skin biopsies with a T-cell infiltrate were found, dendritic cells being more numerous in the latter. The main finding of this study was an uneven distribution of epidermal Langerhans cells and dermal dendritic cells in skin biopsies with a T-cell infiltrate: in skin lesions with an inflammatory lymphoid infiltrate, small clusters of epidermal and dermal dendritic cells admixed with T-lymphocytes (predominantly T-helper/inducer cells) and small blood vessels were present at areas of exocytosis. In skin lesions with a neoplastic lymphoid infiltrate larger, more loosely arranged aggregates of dendritic cells and T-cells were seen. These cell aggregations composed of activated (inflammatory or neoplastic) T-cells and dendritic cells may represent the cutaneous homologue of the secondary T-nodule in the lymph node. Both types of cell aggregates may correspond to the dendritic cell-T cell clusters observed in in vitro induced immune responses.

Does radiation-induced abrogation of skin Langerhans cell functions lead to enhanced incidence of skin tumors in patients with genetic disorders of DNA repair?

A hypothesis is presented which states that persons with the genetic disorders xeroderma pigmentosum and ataxia-telangiectasia, manifested by a deficiency of DNA repair, develop cutaneous tumors due to the elimination of reticuloendothelial system cells (Langerhans cells) in the skin, and the subsequent loss of control of epidermal cellular elements.

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.

Immunologic aspects of acute cutaneous graft-versus-host disease: decreased density and antigen-presenting function of Ia+ Langerhans cells and absent antigen-presenting capacity of Ia+ keratinocytes

Cutaneous graft-versus-host disease (GVHD) provides a unique model for studying the pathogenesis of several important lymphocyte-mediated skin diseases. Morphologic studies have suggested that Ia antigen (Ia)-bearing epidermal Langerhans cells (LC) may be specific targets for destruction in these conditions. Keratinocytes synthesize and express Ia in GVHD and some other lymphocyte-mediated skin disorders; Ia+ keratinocytes, constitutively able to secrete epidermal cell-derived thymocyte activating factor (ETAF)/interleukin 1, may possess antigen-presenting capacity, thus leading to enhanced cutaneous immune responses and disease chronicity. We therefore investigated the fate of Ia+ LC, and the potential antigen-presenting capacity of Ia+ keratinocytes, in a murine model of GVHD. Lethally irradiated C3H/He (H-2k) mice developed acute cutaneous GVHD, and expressed keratinocyte Iak, 8 days after injection of BALB/c (H-2d) bone marrow and spleen cells. Immunofluorescence studies showed a progressive decrease in the density of Ia+ epidermal LC during the evolution of GVHD. This decrease was paralleled by a progressive reduction in the allostimulatory capacity of GVHD epidermal cells (EC) in the allogeneic EC-lymphocyte reaction (ELR). The fall in the density of Ia+ LC, and in EC allostimulatory capacity in both primary and secondary ELRs, was consistently greater in GVHD mice than in mice treated only with x-irradiation. The allostimulatory capacity of GVHD and x-irradiated EC could not be restored by addition of indomethacin or exogenous ETAF to ELR cultures. The decreased allostimulatory capacity was not the result of inhibition of the ELR, since EC from GVHD and x-irradiated mice did not cause suppression when added to control ELR cultures. The capacity of EC to present ovalbumin, purified protein derivative of tuberculin, 2,4,6-trinitrobenzenesulfonic acid coupled to EC, and native cytochrome c (CYTc) to antigen-specific T-cell lines, clones, or hybridomas was reduced in x-irradiated mice and markedly decreased in GVHD mice. The capacity of EC from x-irradiated and GVHD mice to present CYTc fragment 81-104, which does not require further processing or catabolism by accessory cells, was similarly decreased. Taken together, the results indicate that: the function of LC is markedly and progressively impaired in acute GVHD; LC function is also decreased, but to a lesser extent, following x-irradiation alone; and Ia+ keratinocytes from lethally irradiated mice undergoing GVHD do not exhibit antigen-presenting capacity.

Histiocytes in nasopharyngeal carcinoma in relation to prognosis

Forty-nine biopsy specimens of nasopharyngeal carcinoma and 20 biopsy specimens of nasopharyngeal mucosa obtained from non-cancer patients were studied for the presence of T-zone histiocytes (Langerhans' cells and their precursors) and macrophages by immunohistochemical methods with the use of antibodies against S-100 protein and lysozyme (lys), respectively. Patients with dense infiltration of T-zone histiocytes in the primary sites survived longer than those without such infiltration (mean survival times, 8, 39, and 72 months in the patients with the density of -, +, and ++, respectively; P less than 0.005). In contrast, there was no relationship between patient prognosis and density of lys+ macrophages in the tumor tissue (P = 0.33). The distribution of T-zone histiocytes in the tumor tissue was different from that of macrophages. T-zone histiocytes may play an important role in the immune reaction against cancer, probably acting through mechanism different from that of macrophages.

The lymph node in mycosis fungoides: a light and electron microscopy and immunohistological study supporting the Langerhans' cell-retrovirus hypothesis

This paper describes the light and electron microscopy and monoclonal antibody findings in the lymph nodes of nine patients with mycosis fungoides. Four cases showed dermatopathic change characterized by close association between small convoluted T4 lymphocytes and T6 antigen-presenting cells (Langerhans' and indeterminate dendritic cells) in the sinuses and paracortical zones. The T4:T8 ratio was between 3 and 5:1. One case showed dermatopathic change but included large convoluted T4 lymphocytes and occasional T10 lymphocytes. The T4:T8 ratio was 4:1. The antigen-presenting cells were mostly T6 negative (interdigitating reticulum cells). One case showed extensive paracortical expansion by small and large convoluted T4 lymphocytes. The T4:T8 ratio was 20:1. Few B lymphocytes and antigen-presenting cells were present. Two cases showed partial and one case total effacement by atypical lymphoid tissue. This included small and large convoluted T4 lymphocytes and T4 immunoblasts. The T4:T8 ratios were between 30 and 40:1. The changes in their antigen-presenting cell population were complex. Langerhans' cells in one case generally failed to express T6 antigen and in two displayed histiocyte features. In one case, both immature and budding type C retrovirus-like particles were identified in Langerhans cells. One extracellular mature type C virus-like particle was identified in another case. No ultrastructural distinction could be made between similarly sized primary lysosomes and possible intracytoplasmic mature type C retrovirus particles. These findings support the hypothesis that mycosis fungoides may represent an altered dermatonodal cycle resulting from an interaction between retrovirus, Langerhans' cells and lymphocytes.

Monoclonal antibodies and cutaneous T cell lymphoma. Theoretical and practical considerations

The T cell nature of mycosis fungoides and Sézary syndrome was established a decade ago. The recent advent of monoclonal antibodies to T cells and other lymphoid subpopulations has resulted in an explosion of knowledge on the biology of this group of disorders. These reagents have increased our knowledge on thymic differentiation status, pathogenesis, the phenotype of premalignant vs malignant lymphocytic infiltrates, the identification of other previously unrecognized cells within lymphomas, and the phenotype of circulating vs skin lymphocytes. Therapeutic applications may result. These new developments are discussed.

Rheumatoid arthritis and sterile corneal ulceration. Analysis of tissue immune effector cells and ocular epithelial antigens using monoclonal antibodies

Tissue immune effector cells and epithelial surface antigens present in eye tissue of rheumatoid arthritis (RA) patients with sterile corneal ulceration were studied using a large panel of monoclonal antibodies. During periods of active corneal ulceration, conjunctivae and corneas of all RA patients studied contained numerous immune-associated (Ia) antigen-positive tissue macrophages. In 4 of 6 patients, conjunctival or corneal T cell infiltrations were present. In 2 patients, a T cell vasculitis was seen in conjunctival tissue. Conjunctival epithelial cells of all 6 RA patients expressed Ia antigens during active corneal ulceration. These data provide evidence for immune-mediated mechanisms in the pathophysiology of corneal ulceration in RA. Moreover, the expression of Ia antigens by conjunctival epithelial cells may be a useful indicator of disease activity in RA patients with sterile corneal ulceration.

Lymphomatoid papulosis and Hodgkin's disease: are they related?

Two different characteristic types of lymphomatoid papulosis (type A and type B) can be histologically distinguished, that represent the ends of a spectrum. In the present report, two patients are described. One patient with both lymphomatoid papulosis type A and type B lesions for more than 25 years developed Hodgkin's disease (nodular sclerosing type) in the para-aortic and para-iliac lymph nodes. Histologic examination of the skin lesions in the second patient, who had Hodgkin's disease (nodular sclerosing type) in many supradiaphragmatic lymph nodes, showed the characteristic features of lymphomatoid papulosis type A. These findings, together with the results of recent immunohistochemical investigations showing many similarities between the large atypical cells in lymphomatoid papulosis type A lesions and Reed-Sternberg cells in Hodgkin's disease, support the view that lymphomatoid papulosis type A and Hodgkin's disease are closely related conditions. The results of recent studies indicate a close relationship between lymphomatoid papulosis type B and the early stages of mycosis fungoides. Accordingly, the possible relationship between lymphomatoid papulosis types A and B, mycosis fungoides, and Hodgkin's disease is discussed.

OKT 9 reactivity in mycosis fungoides and large plaque (atrophic) parapsoriasis

A monoclonal antibody OKT 9 which detects a determinant expressed by a variety of proliferating cell types has been recently developed. This antibody was used in conjunction with the immunoperoxidase technique to study the cutaneous lymphoid infiltrates of nine patients with mycosis fungoides, one patient with lymphomatoid papulosis, two patients with Sézary syndrome, and ten patients with large plaque atrophic parapsoriasis (a condition which may terminate in overt mycosis fungoides.) OKT 9 reactive cells were identified in all cases of mycosis fungoides examined, in one case of lymphomatoid papulosis, one of two cases of Sézary syndrome, and one of ten cases of large plaque atrophic parapsoriasis. These results suggest that further studies using OKT 9 should be performed to assess whether OKT 9 reactivity may be used as a prognostic marker in cutaneous lymphomas and prelymphomas.

Langerhans cells in granulomatous syphilis

In a case of granulomatous syphilis (transitional state between early and late syphilis), several Langerhans cells (LC) were present in the basal and medial part of the epidermis. Evidence of LC activation was given by the presence of many Langerhans granules, vesicles, a large Golgi apparatus and, sometimes, Golgi complexes. In some LC, signs of degeneration were visible. Langerhans granules surrounded by cytoplasmic material were present in the intercellular space of the epidermis. Apposition of lymphocytes to LC in the dermal space supports the role of LC in immunologic mechanisms. This was further confirmed by signs of phagocytosis in LC. The interaction of LC with intra-epidermal microorganisms (as, for instance, the Treponema pallidum) might be important in the development of the epidermotropic infiltration. This mainly consists of lymphocytes, which sometimes form a pseudolymphoma. A correlation between LC and granuloma formation is suggested.

Predominant cutaneous infiltration by OKT6- and OKT8-positive cells in a case of Sézary syndrome

Using an immunoperoxidase (skin biopsy) and an immunofluorescence (peripheral blood, bone marrow punctate) technique, and monoclonal antibodies raised against peripheral mature lymphocytes, T helper subsets, T suppressor subsets, and Langerhans cells, we found a predominant dermal infiltration with lymphocytes of the suppressor phenotype and a predominant epidermal infiltration with Langerhans cells in a patient with Sézary syndrome (cutaneous T-cell lymphoma, CTCL). Repeated peripheral blood examinations showed an increased percentage of lymphocytes of the helper phenotype. A bone marrow examination revealed a ratio of suppressor/helper subsets of 1:4. The findings in the skin seem to be inconsistent with most of the results of previous studies in patients with CTCL; the significance of these findings is discussed.

Controversies in mycosis fungoides

Most clinicians agree that mycosis fungoides is the prototypic cutaneous T cell lymphoma. However, certain clinical characteristics indicate that this disorder may begin as a reactive rather than a neoplastic process. The concept of a nonneoplastic etiopathogenesis of mycosis fungoides is further supported by recent data on the function of Langerhans cells, a population of epidermal cells known to play a critical role in immune surveillance and the development of contact sensitivity. It has been suggested that chronic occupational exposure to environmental allergens results in persistent antigenic stimulation, leading to a breakdown in immune surveillance and eventually, malignancy. Modern laboratory technics have enhanced the clinician's ability to diagnose and stage mycosis fungoides. Data obtained from such studies have indicated that systemic spread may occur much earlier in the course of disease than has previously been appreciated. The therapeutic implications of such knowledge are as yet uncertain.

Pagetoid reticulosis (Woringer-Kolopp disease). An ultrastructural and immunocytological study

Histopathological, immunocytological and ultrastructural observations are reported in the first case of pagetoid reticulosis (Woringer-Kolopp disease) in Japan. The patient was a 61-year-old woman with multiple skin lesions running a chronic and apparently benign clinical course. Histology of the skin biopsies revealed typical pagetoid appearance of the epidermis due to intraepidermal infiltration of abnormal cells. Ultrastructural investigation showed that the intraepidermal abnormal cells were classified into mycosis fungoides cells, Sézary cells, lymphoblast-like cells, and large blastoid cells and that the mycosis fungoides cells were a major cell population. Intermediate or transitional cells were found between these cells and large blastoid cells were mostly situated in the basal cell layer. By the rosetting assays of the free cell suspensions prepared from the epidermis of the biopsied skin lesions, 93% of the suspended cells were positive for spontaneous rosette formation with sheep erythrocytes. The immunoperoxidase technique demonstrated no cytoplasmic immunoglobulins in almost all the intraepidermal abnormal cells. These results indicate that the intraepidermal abnormal cells are T-lymphocytes. Thus, it is concluded that the present case is a cutaneous T-cell lymphoma of low-grade malignancy showing a prominent epidermotropism. This case is the first description of the disease in Japan.

The use of a double-label immunoperoxidase monoclonal antibody technique in the investigation of patients with mycosis fungoides

Using a double-labelling immunoperoxidase and monoclonal antibodies raised against T helper and T suppressor cells and Langerhans cells, we have found that the clinically involved skin of seventeen mycosis fungoides (MF) patients shows an increase in number of Langerhans cells which are in contact with T helper lymphocytes. T suppressor lymphocytes are also present, but are generally seen singly situated at a distance from the T helper/Langerhans cell clusters.

Morphologic and morphometric study of the two main cell lineages involved in mycosis fungoides: the lymphoid cells and the Langerhans cells

A comparative light and electron microscopic study was carried out on skin biopsies from 5 mycosis fungoides patients (stages II and III). In addition, certain zinc-iodide-osmium (ZIO) procedures that selectively reveal the Langerhans cells (LC) were also applied. Several morphometric analyses, such as relative frequency, cell size, nuclear:cell ratios and nuclear contour indexes, were performed. Two main cell lineages were found in the dermal infiltrate: the lymphoid cells, represented by lymphoblastlike cells (LB), lymphocytes (L), and mycosis fungoides cells (MFC), and the Langerhans cells. A pattern of cellular organization of the dermal infiltrate was recognized. The LC appeared as the "organizing" cell. The morphometric study indicated that all LB, L, and MFC have the chance, at the same time, to be in contact with a LC. The application of the ZIO procedures clearly indicated a "translocation" of the LC, since they were scarce or absent from the epidermis and numerous in the dermis. Evidence is presented indicating that differentiation of LB into L and malignant transformation of L into MFC are processes occurring predominantly in the dermis. It is postulated that in the chronic stages of mycosis fungoides, L-LC contacts occur mainly in the dermis and not in the epidermis and that the development of malignant clones may occur in the dermis.

Home ultraviolet phototherapy of early mycosis fungoides: preliminary observations

Thirty-one patients with early mycosis fungoides (MF) and three patients with parapsoriasis en plaques were treated with ultraviolet phototherapy (280 to 350 nm) at home using a commercially available light source containing four Westinghouse FS40 lamps. A complete clinical and histologic remission of disease, lasting for a median duration in excess of 18 months, was achieved in nineteen patients (61%) with MF. Although higher complete response rates generally are achieved with other therapeutic modalities, ultraviolet phototherapy with its minimal adverse effects may be indicated for selected patients. Controlled studies are encouraged to evaluate the full potential of conventional phototherapy in the management of MF.

Combined immunological and histochemical analysis of skin and lymph node lesions in histiocytosis X

The immunological phenotype of the cells involved in skin and lymph node lesions from two cases of histiocytosis X (H-X) were analysed by immunofluorescence techniques using combinations of heterologous and monoclonal antisera to Ia-like antigen and human cortical thymocyte (HTA-1) determinant. These cells were also characterised by a new technique using simultaneous immunofluorescence and enzyme histochemistry for acid phosphatase (ACPase). The major cell type in the lesions was found to express the same Ia+, HTA-1+ phenotype as normal epidermal Langerhans' cells (LC) and was unreactive for ACPase. Additional cell types included Ia-, HTA-1- multinucleate giant cells and residual lymphoid populations. These findings endorse previous concepts that H-X is a proliferation of abnormal LC and emphasise the heterogeneous nature of the cells involved in the disease.

In situ identification of Langerhans cells in the dermal infiltrate of cutaneous T cell lymphoma

A population of cells showing the surface phenotype of Langerhans cells (LCs) was identified in the dermal infiltrates of cutaneous T cell lymphoma (CTCL). Peroxidase-conjugated OKT6, a monoclonal antibody reactive with epidermal LCs, was used to directly label frozen tissue sections of diseased skin from twenty-three patients with CTCL, two patients with secondary cutaneous involvement by a B cell lymphoma, and three patients with lymphocytoma cutis. OKT6-reactive cells represented a significant although minor population in the dermal infiltrate of twenty-two of the twenty-three CTCL biopsies, accounting for up to 5% of the cells. Double-labeling studies revealed that the OKT6-positive cells also exhibited Ia but not T cell antigens. Since OKT6-reactive cells were not found in either the B cell lymphomas or lymphocytoma cutis, their presence in a malignant infiltrate is suggestive of a T cell neoplasm.