Clinical manifestations of cutaneous graft-versus-host disease after allogeneic haematopoietic cell transplantation: long-term follow-up results in a single Turkish centre

The aim of this study was to evaluate the clinical manifestations of cutaneous graft-versus-host disease (GVHD) developed after allogeneic haematopoietic cell transplantation. In all, 67 patients were evaluated: 49 patients developed acute GVHD, 17 patients developed de novo chronic GVHD and 29 developed secondary chronic (15 limited, 14 progressive) GVHD following acute cutaneous GVHD. Of the 46 patients with chronic GVHD, lichenoid lesions were observed in 32 and sclerodermoid lesions were observed in 12. In four patients with sclerodermoid cutaneous GVHD, these lesions occurred after a lichenoid phase. Oral lesions were present in 61% of the patients and six of them had only oral mucosal involvement without any skin lesions. Nail lesions were observed in 31% of the patients. During the follow-up period 15 patients with GVHD died and in 7 of them the cause of death was related to chronic GVHD. In conclusion, GVHD has a wide spectrum of cutaneous manifestations, which can be used as an important tool for the early diagnosis of the disease.     

Annular plaques: An unusual manifestation of graft-versus-host disease

Chronic cutaneous graft-versus-host disease (GVHD) classically presents with lichenoid papules or sclerotic plaques. This case highlights an unusual clinical manifestation of chronic GVHD and demonstrates that the skin morphology of chronic GVHD and cutaneous lymphoma may be similar. We report for the first time a case of annular scleroderma-like graft-versus-host disease in a patient following allogeneic stem cell transplant for CD30+ anaplastic large cell lymphoma. Treatment of these skin lesions with ultraviolet A1 (UVA1) phototherapy resulted in significant improvement.     

Immunohistochemical Study of Graft-versus-Host Reaction (GVHR)-Type Drug Eruptions

Skin biopsies of graft-versus-host reaction (GVHR)-type drug eruptions in the acute phase were compared immunohistochemically with those in the chronic phase and also with non-GVHR type drug eruptions in the acute phase. Predominance of CD8⁺ T cells in the epidermal infiltrates, reduction in the number of epidermal OKT6⁺ dendritic cells (Langerhans cells), and increased expression of HLA-DR and ICAM-1 on keratinocytes were observed in the acute phase of GVHR-type, but not in either the chronic phase of GVHR-type or the acute non-GVHR type. These findings were similar to those of previous reports on skin lesions of acute GVH disease (GVHD) seen after bone marrow transplantation. Therefore, immunohistochemistry is not useful for differential diagnosis between acute GVHR-type drug eruptions and acute cutaneous GVHD. These findings also indicate that similar immunomechanisms may be involved in the pathogenesis of both GVHR-type drug eruptions and cutaneous GVHD.     

Cutaneous graft-versus-host disease: a guide for the dermatologist

Graft-versus-host disease (GVHD) is defined by the aggregation of clinical and pathological manifestations in a recipient of allogeneic stem cells or bone marrow transplantation in which specific immunological as well as nonspecific phenomena lead to characteristic features. GVHD is one of the major complications after hematopoietic stem cell transplantations and responsible for posttherapeutic morbidity, mortality and decrease in quality of life of those patients. GVHD is critically induced and maintained by donor immunocompetent cells that particularly attack epithelia of fast proliferating tissues such as those from the liver, gastrointestinal tract and skin. On the basis of the time of presentation, cutaneous GVHD has been originally divided into an acute and chronic disease. The latter has traditionally been further subclassified into a more epithelial or lichenoid and a predominantly dermal or sclerodermoid form. With respect to the growing importance of this therapeutic procedure and increasing numbers of outpatients presenting with chronic GVHD, this article summarizes the updated knowledge on this disease focused for the dermatologist, and additionally it emphasizes the recent consensus documents on the various aspects of chronic GVHD of the National Institute of Health.     

A Case of Chronic GVHD Following Bone Marrow Transplantation from a Phenotypically HLA-Matched Unrelated Donor

A 45-year-old male with chronic myelocytic leukemia who received a bone marrow transplantation from a phenotypically HLA-matched unrelated donor developed chronic GVHD on day 100 post transplantation. He developed a slight fever, malaise, hepatic dysfunction and extensive itchy erythema with scaling over his entire body. The inflammatory skin lesion developed into erythroderma in about two weeks. H&E staining of a skin biopsy revealed eosinophilic bodies and a lymphocytic infiltration in the dermis and epidermis, which were compatible with the early phases of chronic GVHD. Immunohistochemistry revealed that keratinocytes expressed dense HLA-DR and ICAM-1 epitopes. Langerhans cells (CD1a⁺ cells) had disappeared from the epidermis. Many T cells (CD3⁺ cells) had migrated into the epidermis as well as into the reticular dermis. The majority of the T cells in the epidermis were CD8⁺ cells, while almost all the T cells in the dermis were CD4⁺ cells. These immunohistochemical features were similar to those previously reported for acute cutaneous GVHD. Despite the corticosteroid therapy, the eruptions did not disappear. The patient was then treated with whole body bath-methoxsalen (Oxsoralen®) plus ultraviolet A (UVA). The bath-psoralen plus UVA therapy was effective in this patient.     

Transfusion-associated graft-versus-host disease: an in situ hybridization analysis of the infiltrating donor-derived cells in the cutaneous lesion.

BACKGROUND: Acute graft-versus-host disease (GVHD) can occur after a blood transfusion. OBJECTIVE: In order to elucidate the pathomechanisms responsible for transfusion-associated GVHD, infiltrating donor-derived cells in a cutaneous lesion were analyzed. METHODS: A skin sample obtained from a 69-year-old woman who developed fatal GVHD after blood transfusions from male donors was studied by performing in situ hybridization (ISH) with a Y-chromosome-specific probe. RESULTS: The cell infiltrates comprised mainly CD3+ T lymphocytes. Immunohistochemistry and ISH in combination demonstrated that 99% (182/184) of the Y-body-positive cells were CD3+. Y bodies were observed in 80% of the CD8+ cells in the epidermis and dermoepidermal junction and in 77 and 45% of the CD8+ and CD4+ cells, respectively, in the dermis. CONCLUSION: These findings suggest that both CD4+ and CD8+ cells of donor origin were involved in the development of cutaneous GVHD.     

Proliferative activity of CD8(+) T cells as an important clue to analyze T cell-mediated inflammatory dermatoses

Abstract To elucidate the pathogenesis of T cell-mediated inflammatory skin diseases, we examined the exact sites where CD8(+) T cells proliferate, correlating them with the localization of antigen-presenting dendritic cells. We performed CD8/Ki-67 double immunohistochemical staining and single staining for CD1a, CD68, and factor XIIIa on sections of paraffin-embedded tissue samples of inflammatory dermatoses in which T lymphocytes are thought to play a crucial role. The dermatoses were lichen planus (12 samples), acute graft-versus host disease (GVHD) (12 samples), chronic GVHD (10 samples), spongiotic dermatitis (8 samples) and psoriasis (7 samples). Labelling for Ki-67 among CD8(+) T cells was predominantly observed in the subepidermal lymphoid infiltrate, and was scanty in the epidermis. This suggested that proliferation of CD8(+) T cells occurred preferentially in the dermis. The labelling index for Ki-67 among dermal and epidermal CD8(+) cells was quite different among the different diseases studied (P < 0.05). They were rich in the subepidermal portion of the dermis of spongiotic dermatitis, acute GVHD and chronic GVHD, but rare in the dermis of psoriasis and lichen planus. A moderate infiltrate was also observed in lesional epidermis of spongiotic dermatitis, acute GVHD and chronic GVHD, whereas they was almost none in the epidermis of psoriasis and lichen planus. CD1a(+) dermal dendritic cells were densely distributed within the lymphoid infiltrate in the affected dermis of spongiotic dermatitis, psoriasis and lichen planus, whereas they were minimal in GVHD. These dermal dendritic cells are candidates as stimulators on T cells in the dermis. In conclusion, the proliferative status of T cells could be an important clue in the elucidation of the pathophysiology of T cell-mediated inflammatory dermatoses. Received: 13 December 2000 / Revised: 24 April 2001 / Accepted: 11 July 2001     

Dermatologic Treatment of Cutaneous Graft Versus Host Disease

Cutaneous involvement in graft versus host disease (GVHD) after allogeneic hematopoietic cell transplant can be separated into acute GVHD (aGVHD), lichenoid chronic GVHD (cGVHD) and sclerodermatous cGVHD. It seems clear that these syndromes result from different mechanisms and entail different treatment approaches. Standard treatment of cutaneous aGVHD involves the intensification of immunosuppressive therapy with adequate topical supportive management. In skin-limited disease, phototherapy has shown promising results. In cutaneous cGVHD, the combination of corticosteroids and cyclosporine (ciclosporin) is the recommended therapy, and other immunosuppressants may be added depending on whether lichenoid or sclerodermatous lesions are present. High response rates to phototherapy have been found in lichenoid disease, while sclerodermatous disease responds better to etretinate or extracorporeal photochemotherapy. Localized cutaneous cGVHD may be treated with topical corticosteroids alone. Few reports on the effect of treatments in GVHD clearly describe the cutaneous involvement and the influence of the treatment on the skin. Therefore, dermatologists should be deeply involved in the diagnosis and treatment of GVHD, and good dermatologic grading systems should be developed. Theses changes will increase our knowledge of cutaneous GVHD, and relevant data in the evaluation of the effect of therapy in the disease will be obtained.     

Histochemical and ultrastructural study of diffuse melanoderma after bone marrow transplantation

Summary Hyperpigmentation is a well-recognized feature of cutaneous graft-versus-host disease (GVHU). and is usually restricted to sites where lichenoid or sclerodermiform lesions have occurred. Since 1975, two of 745 patients treated by allogeneic bone marrow transplantation in our institution have developed diffuse melanoderma which differed considerably from the classic presentations. They both developed acute GVHD. then lichen planus-like chronic lesions and diffuse melanoderma. Histology of biopsies of the pigmented skin showed intense pigment deposition in the basal and suprabasal layers, and in dermal macrophages. On split-dopa, melanocyte counts were 98 and 93 per Held, respectively. Electron microscopy showed melanocytes protruding into the dermis, and dark melanosomes in all epidermal layers and in macrophages. These findings were suggestive of post-inflammatory hyperpigmentation. In bone marrow recipients, de nova melanoderma is a rare event which could represent a feature of cutaneous GVHD in pigmented subjects.     

Late appearance of acute graft-vs-host disease after suspending or tapering immunosuppressive drugs

BACKGROUND: Graft-vs-host disease (GVHD) is divided into acute and chronic phases based on time and clinical and histological features. The criterion of 100 days after transplantation for separating acute GVHD from chronic GVHD has been challenged on the following points: (1) the lichenoid rash of chronic GVHD may be observed as early as day 31 and acute GVHD may persist after day 100 in some cases, and (2) specific histological features do not consistently separate acute from chronic GVHD defined as the number of days after transplantation. However, the appearance of acute cutaneous GVHD after day 100 is not well established. OBSERVATIONS: Three patients developed a rash with clinical and histological features of acute GVHD between days 153 and 192 after allogeneic bone marrow transplantation or peripheral blood stem cell transplantation. In all patients, the late flare of acute GVHD occurred after tapering or suspending the immunosuppressive regimen with cyclosporine or corticosteroids, and was accompanied by stigmata of chronic GVHD in other target organs. CONCLUSIONS: The rash of acute GVHD may be observed as late as 192 days after transplantation, especially after tapering or suspending the immunosuppressive drugs, and should be considered in the differential diagnosis of late erythematous eruptions after transplantation.     

PUVA therapy for chronic cutaneous graft-vs-host disease

Chronic graft-vs-host disease (GVHD) is an immunologic disorder frequently occurring as a late sequelae of allogeneic bone marrow transplantation and characterized in the skin with lichenoid or sclerodermoid lesions. Systemic immunosuppressive agents such as corticosteroids or cyclosporine are usually required to control the disease. Therapy with psoralen and UVA (PUVA) has recently been shown to be effective for skin and oral mucosa in a few cases of GVHD. We present our experience with PUVA in six patients, five with lichenoid and one with sclerodermoid GVHD. None of these patients had significant systemic involvement. All five patients with lichenoid GVHD showed clinical improvement after PUVA therapy. Three of these patients had complete clearance of skin lesions. Clinical clearance of the disease was accompanied by microscopic clearance. The patient with sclerodermoid GVHD did not respond to therapy. No significant complications or exacerbation of systemic disease occurred. We confirm that PUVA is an effective and safe therapy for the cutaneous manifestations of lichenoid chronic GVHD. We postulate that PUVA therapy clears chronic lichenoid GVHD by selective cytotoxicity for the activated lymphoid cells in the inflammatory infiltrate.     

The lichen planus like and sclerotic phases of the graft versus host disease in man: an ultrastructural study of six cases

Skin biopsies from 6 patients with chronic graft-versus-host disease (GVHD) were studied ultrastructurally. The 6 patients experienced an early lichenoid phase 65-135 days after the graft and 3 of them progressed to a late sclerotic phase 200-340 days after the grafting Damage to the basal membrane and to the keratinocytes of the basal layer and low spinous layers, and presence of epidermal regenerative cells were features common to the lichenoid phase of chronic GVHD and idiopathic lichen planus. The late sclerotic phase of GVHD with persistence of basal cell injury, normal periodicity and structure of the collagen fibres and numerous active fibroblasts in the upper third of the dermis were findings that distinguished GVHD from scleroderma. Satellite cell necrosis, i.e. lymphocyte satellites of necrotic keratinocyte, was observed in the two phases of chronic GVHD. Thus at the ultrastructural level the early phase of chronic GVHD mimics lichen planus, but the late sclerotic phase is distinct from scleroderma.     

CD1a+, CD3+, CD4+, CD8+, CD68+ and cutaneous lymphocyte-associated antigen-positive cells in Bowen's disease

BACKGROUND: Bowen's disease (BD) is a squamous cell carcinoma in situ that rarely invades into the underlying dermis. However, little is known about its immunohistology. Objectives To evaluate the relationship between the cytological properties of the tumour cells in BD and the host immune response. METHODS: We examined the expression of p53, proliferating cell nuclear antigen (PCNA) and Ki67 antigen, and the number of mitotic cells, together with the number of intratumoral and dermal infiltrating CD1a+, CD3+, CD4+, CD8+, CD68+ and cutaneous lymphocyte-associated antigen (CLA)+ cells in 18 cases of genital BD. RESULTS: When compared with normal genital skin (n = 10), there was a significantly higher number of mitotic cells as well as higher expression of p53+, PCNA+ and Ki67+ cells in BD. There was significant mutual correlation between CD3+, CD4+ and CD68+ cells in the tumoral epidermis. The number of CD1a+ Langerhans cells significantly decreased in BD epidermis; however, dermal CD1a+ cells were increased. Interestingly, numbers of dermal CD1a+ cells significantly correlated with those of intratumoral CD3+, CD4+ and CD68+ cells. In situ hybridization for human papillomavirus (HPV) demonstrated that HPV-infected BD had significantly less infiltration of intratumoral CD3+ cells and CLA+ cells. CONCLUSIONS: The present data suggest that dermal CD1a+ cells may participate in the immune surveillance and that HPV infection may interfere with the intratumoral infiltration of CLA+ cells in BD.     

Immunohistochemical Studies of Infiltrating Cells in Early and Chronic Lesions of Psoriasis

The expression of surface antigens on infiltrating cells, epidermal keratinocytes, and dendritic cells in biopsy specimens from 31 patients with psoriasis was examined immunohistochemically. The specimens were divided into early-phase and chronic-phase groups and then examined in a double blind manner. Among the infiltrating cells in the epidermis, CD4-positive cells were dominant in the early phase; CD8-positive cells were dominant in the chronic phase, resulting in a markedly decreased CD4/CD8 ratio in the latter. On the other hand, among the infiltrating cells in the dermal papillae, CD4-positive cells were dominant in both the early and chronic phases; both CD4-positive and CD8-positive cells were more dominant in the chronic phase than in the early one. However, the CD4/CD8 ratios were decreased in both the dermal papillae and the epidermis in the chronic phase. CD1-positive dendritic cells (probably Langerhans cells) were more numerous in the chronic phase than in the early phase. There were no significant differences between the early and chronic phases with regard to the expression of HLA-DR and HLA-DQ antigens on the infiltrating cells. However, the HLA-DR antigens and ICAM-1 (intercellular adhesion molecule-1) were more strongly expressed on epidermal keratinocytes in the chronic phase than in the early phase. LFA-1α (lymphocyte function-associated antigen-1α)-positive cells were also significantly more numerous in the chronic phase than in the early one, consistent with the expression of HLA-DR antigens and ICAM-1 on keratinocytes mentioned above. On the other hand, VLA-4 (integrin α₄β₁) positive cells were expressed more abundantly in the epidermis in the early phase than in the chronic phase. These results suggest, first, that the chronic phase of psoriasis is as immunologically active as or more active than the early phase. Second, CD4-positive T cells are more important than CD8-positive T cells in the early phase of psoriasis; CD8-positive rather than CD4-positive T cells are more important in the chronic phase. Third, the LFA-1/ICAM-1 pathway may play an important role with regard to cell adhesion of the infiltrating cells in the psoriatic lesions in disease exacerbation or prolongation, whereas the VLA-4/VCAM-1 (vascular cell adhesion molecule-1) pathway may be more important in disease onset.     

Cutaneous graft-versus-host reaction: prognostic features seen by light microscopy

Acute graft-versus-host disease (GVHD) is a severe complication of bone marrow transplantation. The diagnosis may be made and its course followed by serial skin biopsies. The degree of epidermal change has been used as a guideline in grading each biopsy, but great variation may be found within each grade, especially grade 2 (basal cell vacuolization and dyskeratosis). To find a histologic parameter that is prognostic of more severe acute GVHD, we examined retrospectively the serial biopsies of 54 patients. When we studied early cutaneous graft-versus-host reaction (GVHR), represented by the grade 2 biopsies, the number of dermal and epidermal mononuclear inflammatory cells correlated positively with the probability of developing more severe acute GVHD. In addition, the patients who had more severe acute GVHD tended to have an earlier appearance of cutaneous histologic changes. None of the other histologic parameters examined in these grade 2 biopsies were found to be predictive of GVHD progression. In addition, no histopathologic parameters in these grade 2 biopsies were predictive of the subsequent development of chronic GVHD.     

Immunopathologic study of erythema dyschromicum perstans (ashy dermatosis)

Erythema dyschromicum perstans (EDP) is a pigmentary disease of unknown etiology in which damage to basal cells is thought to be mediated by adhesion molecules. The aim of this study was to characterize the histopathology and immunopathology of EDP. Forty-three patients from Medellín, Colombia, with the diagnosis of EDP were evaluated. Skin biopsy specimens were obtained for histopathology and immunohistochemistry, using monoclonal antibodies directed against the following markers: CD4, CD8, CD56, CD1a, CD68, CLA, HLA-DR, ICAM-1 and LFA-1alpha. A dermal lymphocytic infiltrate was observed in all cases, with a perivascular location in 86%. Other histologic features included melanophages in all specimens, vacuolization of the basement membrane zone (BMZ) 58% and exocytosis of lymphocytes (53.5%). The mean number of total leukocytes was 1510 cells mm-2 of tissue. There was a predominance of CD8+ T lymphocytes in the dermis and HLA-DR+, ICAM-1+ keratinocytes in the epidermis. Exocytosis of cutaneous lymphocyte antigen (CLA)+cells was observed in areas of BMZ damage, suggesting that response to antigenic stimulation may play a role in the development of EDP.     

The lymphocytic infiltrate in acute cutaneous allogeneic graft-versus-host reactions lacks evidence for phenotypic restriction in donor-derived cells

The lymphocytic subtypes effecting allogeneic graft-versus-host disease (GVHD) are unknown. We studied 35 skin biopsy specimens from 19 women transplanted with bone marrow from men for patterns and time course of infiltration of the skin by Y chromosome-bearing lymphocytes using in situ hybridization. Immunophenotypic analysis was performed on serial sections. Significant numbers of donor cells were first observed by day 13 after bone marrow transplantation (BMT), although a few cells were noted at earlier time points. The quantity of donor lymphocytes in the dermis correlated with the diagnosis of GVHD. For specimens with grade 1 features, only rare cells bore the Y chromosome, whereas the majority of lymphocytes in grade 2 tissues, whether heavily inflamed or not, contained the Y chromosome. These lymphocytes were predominantly CD4+ with fewer CD8+ and CD56+ cells in the dermis and epidermis. No concentration of a specific subtype in the epidermal compartment was observed. These data do not support the observation that a cutaneous graft-versus-host reaction (GVHR) is mediated primarily by CD8+ lymphocytes. Several effector cell populations may mediate a cutaneous GVHR with further variation over time and in BMTs between different individuals.     

In situ characterization of cellular infiltrates in lupus vulgaris indicates lesional T-cell activation.

Skin biopsy specimens from nine patients with lupus vulgaris were examined in situ by means of monoclonal antibodies directed against phenotypes of lymphocyte subsets, Langerhans cells, HLA-DR antigens, and interleukin 2 receptor. The epidermis showed prominent changes, including intense expression of HLA-DR on keratinocytes, increase in epidermal cell layers, moderate to high Langerhans cell hyperplasia, and infiltration by CD3+ pan-T cells as well as CD8+ (cytotoxic/suppressor) and CD4+ (helper/inducer) T cells. The predominant lymphocyte in the dermal granulomas was the activated CD3+ T cell, expressing major histocompatibility complex class II antigens and interleukin 2 receptor. CD4+ and CD8+ cells were randomly distributed among the epithelioid cells, which showed intense staining for major histocompatibility complex class II antigens. In all except two patients, the CD4+ population was greater than that of the CD8+ cells. CD1+ Langerhans cells were scattered in moderate numbers in the dermal granulomas. Acid-fast bacilli were conspicuously absent in the biopsy specimens. These features suggest that T-cell activation and Langerhans cell hyperplasia are prominent features of dermal tuberculosis.     

Comparison of the distribution and numbers of antigen-presenting cells among T-lymphocyte-mediated dermatoses: CD1a+, factor XIIIa+, and CD68+ cells in eczematous dermatitis,psoriasis, lichen planus and graft-versus-host disease

Antigen-presenting cells (APCs) participate in the initiation of the inflammatory process in various immune-mediated dermatoses through the activation of antigen-specific T lymphocytes. The skin contains several different subsets of APCs. To investigate the role of these APCs in T-cell immune-mediated inflammation, we examined the distribution and numbers of epidermal and dermal CD1a(+) dendritic cells (DCs), factor XIIIa(+) dermal DCs, and CD68(+) macrophages in five T-cell-mediated inflammatory skin diseases. Immunohistochemistry of CD1a, factor XIIIa, and CD68 was performed using paraffin-embedded tissue obtained from a total of 51 patients with eczematous dermatitis (histologically spongiotic dermatitis), psoriasis, lichen planus, acute graft-versus-host disease (GVHD), and chronic GVHD. The numbers of positive cells for each staining were compared with those in site-matched normal skin control specimens from aged-matched subjects. In spongiotic dermatitis and lichen planus, the numbers of epidermal and dermal CD1a(+) cells and factor XIIIa(+) cells were significantly greater than in normal control skin, while in psoriasis only factor XIIIa(+) cells were significantly increased in number. Acute and chronic GVHD showed a reduced number of dermal CD1a(+) cells. Interestingly, factor XIIIa(+) cells were decreased in acute GVHD while they were increased in chronic GVHD. There was a significant reduction in epidermal CD1a(+) cells in acute GVHD, but not in chronic GVHD. The differences in the numbers of APCs in lesional skin appeared to reflect differences in the pathophysiology of these inflammatory skin diseases.     

The effect of in vivo interferon-gamma on the distribution of LFA-1 and ICAM-1 in normal human skin

Lymphocyte function associated antigen 1 (LFA-1) and its ligand intercellular adhesion molecule 1 (ICAM-1) are cell surface adhesion molecules important in many lymphocyte-mediated responses. Recent in vitro studies have demonstrated that the cytokine interferon-gamma (IFN-gamma) can induce ICAM-1 expression by keratinocytes, and that lymphocytes adhere to IFN-gamma treated keratinocytes. In view of the importance of keratinocyte/lymphocyte interactions in the pathogenesis of cutaneous disease, we have examined the effects of in vivo IFN-gamma on cutaneous expression of LFA-1 and ICAM-1. Fourteen volunteers received intradermal IFN-gamma (dose: 1 or 10 micrograms) daily for 3 d. Biopsy was obtained on day 6. Cryostat sections were stained by the peroxidase antiperoxidase technique employing murine monoclonal antibodies to CD11, CD18, and ICAM-1. IFN-gamma intensified ICAM-1 expression by dermal endothelial cells and induced keratinocyte expression of ICAM-1. Furthermore, after administration of 10 micrograms of IFN-gamma LFA-1 positive (LFA + ve) lymphocytes were observed along the basement membrane zone closely related to ICAM-1 + ve basal keratinocytes and also surrounding dermal endothelium. Exposure to IFN-gamma induced expression of both CD11a and CD18 antigens on epidermal Langerhans cells. These studies suggest that the distribution of adherence molecules expression within cutaneous tissue in vivo is modulated by IFN-gamma, and that these alterations may be important in interactions involving cutaneous immunocompetent cells.