Expression of human lymphocyte antigen (HLA)-DR on tumor cells in basal cell carcinoma

Immunohistologic studies of eight patients with basal cell carcinoma were undertaken using a series of monoclonal antibodies. In all of the patients, the majority of dermal infiltrates reacted with OKT3 and OKIa1 (HLA-DR), with a slight predominance of OKT4+ helper/inducer T cells (the mean OKT4/OKT8 ratio was 1.8). Both OKT4+ and OKT8+ cells were seen infiltrating the tumor masses. In addition, in five cases, human lymphocyte antigen (HLA)-DR was demonstrated on some tumor cells close to a vast number of HLA-DR+ infiltrates surrounding the carcinoma, but not on epidermal keratinocytes and tumor cells devoid of the HLA-DR+ infiltrates. A considerable number of OKT6+ dendritic cells were also observed surrounding the carcinoma. Staining with OKB7 and OKM1 revealed negligible reactive cells, and virtually none of the dermal infiltrates reacted with Leu-7 (HNK-1). These findings suggest that in addition to varied immunologically competent cells, expression of HLA-DR antigen on tumor cells may participate in a cellular immune reaction, a defense mechanism against tumor cell proliferation in basal cell carcinoma.     

In situ characterization of cells in the dermal infiltrates of lepromin reaction using monoclonal antibodies

A study was made on the in situ characteristics of dermal infiltrates in the early and late lepromin reaction with monoclonal antibodies defining T cell subsets, Langerhan cells and Ia like antigens. The early reaction (24 hrs) was elicited either with standard Dharmendra lepromin or leprosin-A and the late reaction (3-4 weeks) was elicited with standard Dharmendra lepromin. In all, 15 biopsies were studied. Most lymphocytes in the infiltrates of both the lepromin and leprosin reactions were positive for OKT 11, Leu 3a, OKT 8 and Ia like antigens indicating thereby the presence of activated T cells. A high proportion of OKT6 + cells were also noticed in the infiltrates of these reactions. In the late reaction, the lymphocytes in the granulomas were predominantly activated T lymphocytes expressing OKT 11, Leu 3a, OKT 8 and Ia like antigens. Leu 3a + cells were scattered diffusely amidst the epithelioid cells. In contrast, OKT 8 + cells were present mainly in the peripheral region of the granuloma. A small proportion of OKT6 + cells were also seen in these granulomas. Ia like antigens and T6 antigens were not discernible on the epithelioid cells. No difference in the number of OKT6 + epidermal langerhan cells was observed in the various types of reactions.     

Immunohistologic studies in Schamberg's disease. Evidence for cellular immune reaction in lesional skin

We studied eight cases of Schamberg's disease immunohistologically by using monoclonal antibodies. The dermal infiltrate was composed of Leu-1-reactive T cells, OKT6-reactive Langerhans' cells, and Leu-M5-reactive (Leu-M5+) macrophages. Among them, the major population consisted of T cells with the predominance of Leu-3a-reactive (Leu-3a+) T cells over Leu-2a-reactive (Leu-2a+) T cells. On the other hand, the epidermotropic mononuclear cells consisted of Leu-2a+ and Leu-3a+ T cells without any predominant pattern, and Leu-M5+ macrophages. Furthermore, note that a pemphiguslike intercellular staining pattern was observed in the epidermis in most of the cases, when the sections were stained either with anti-HLA-DR antibody or with OKT6, suggesting the HLA-DR antigen expression on the keratinocyte surface and possibly an enlargement of Langerhans' cells. Based on these immunohistologic findings, we think that Langerhans' cells play an important role in the pathomechanism of Schamberg's disease, and that cellular immune reactions are taking place in the lesional skin.     

Subpopulations of mononuclear cells in microscopic lesions of psoriatic patients. Selective accumulation of suppressor/cytotoxic T cells in epidermis during the evolution of the lesion

The age of microscopic lesions in psoriatic subjects was assessed from the stacking characteristics in the horny layer and related to type and density (cells/tissue volume) of mononuclear cells in the epidermis and the dermis determined by immunoperoxidase methods using monoclonal antibodies. Pan T cells (Lyt-2+, Lyt-3+, Leu-4+, OKT3+), T helper cells (Leu-3a+, OKT4+), T suppressor/cytotoxic cells (Leu-2a+, OKT8+), Ia+ cells and monocytes (OKM2+, BRL alpha mono+) were determined in epidermis and dermis. The psoriatic lesion was divided into regions underneath a parakeratotic and an orthohyperkeratotic/hypergranular portion of the horny layer and contrasted with perilesional and uninvolved psoriatic skin as well as with healthy skin. In the various regions and skin layers, the cell density was highest in parakeratosis and decreased toward normality with decreasing histologic abnormality. The relation between epidermal and dermal cell densities of the T-cell subsets was modified in the involved psoriatic skin with a selective preponderance of T suppressor/cytotoxic cells in the epidermis. The accumulation was present in the youngest lesion found (3 days) and cell densities were unchanged in older lesions. The findings suggests that the altered relationship in the subsets of T cells has an important role during the induction and progress of the psoriatic process in the skin.     

Immunocompetent cells of fixed drug eruption

The positive provocation test reactions of the skin of six patients with fixed drug eruption (FDE) were studied from timed skin biopsies taken between 2 hours and 9 days after the appearance of FDE. Monoclonal antibodies to the following immunocompetent cell surface epitopes were used: T3, T4, T6, T8, T9, M1, Ia1, Drc, Leu7 and B cell. The dermal infiltrate comprised 60-80% of T lymphocytes at all the times studied. Cells with T4 and T8 epitopes were displayed in similar numbers. A transient decrease in the number of T6+ cells of the epidermis could be detected with a simultaneous and also transient increase of the T6+ cells in the dermis, which suggests a possible traffic of Langerhans' cells from the epidermis to the dermis. The epidermal Ia1+ cells showed changes similar to but less marked than the T6+ cells. The number of the dermal Ia1+ cells increased continuously. In the late biopsies these Ia1+ cells comprised up to 90% of the infiltrating cells. Except for the finding of a reduction of T6+ and Ia1+ epidermal cells, the cellular kinetics of FDE are similar to those seen in both cutaneous immunological and irritant reactions.     

Immunohistologic identification of antigen-presenting cells in cutaneous sarcoidosis

Considerable evidence exists to show that activated T lymphocytes preferentially accumulate at sites of disease activity in sarcoidosis. Langerhans cells, which can be recognized by reactivity with an antibody to the T6 antigen are thought to play a primary role in T-lymphocyte activation by the skin, a tissue frequently involved in sarcoidosis. This immunohistologic study examined the distribution of OKT6-positive cells and surface expression of HLA-DR antigen in cutaneous sarcoid lesions. Skin specimens stained with an anti-HLA-DR antibody demonstrated diffuse staining of the granulomas. In addition, keratinocytes, which do not normally express HLA-DR antigens, were found to stain with monoclonal antibody to HLA-DR in an intercellular pattern. Examination of specimens for OKT6-reactive Langerhans cells revealed significantly greater concentrations in the epidermis overlying sarcoidal granulomas (33 +/- 7 cells/mm) than in the epidermis of age-, sex-, and race-matched controls (11 +/- 3 cells/mm, p less than 0.001). Of greater importance was the demonstration that significant numbers of OKT6-positive cells were present within the dermal sarcoid granulomas (19-208/mm2) in a distribution that paralleled that of Leu-3a-positive T lymphocytes. These data suggest that the epidermis may participate in activation of lymphocytes in cutaneous sarcoidosis, and implicate OKT6-positive cells in granuloma formation.     

Increased number of OKT6-positive dendritic cells in the hair follicles of patients with alopecia areata

In 6 patients with untreated alopecia areata in the progressive stage, 6 in the stationary stage, and 6 normal individuals as controls, an in situ analysis of OKT6-positive dendritic cells in hair follicles, and peribulbar and intrabulbar infiltrates was performed using the avidin-biotin-peroxidase method with monoclonal antibodies. In controls, OKT6-positive dendritic cells were distributed only in the upper portions of hair follicles and were not observed in the bulbar area, and the percentage of these cells among all epithelial cells of the hair follicles was 1.0 +/- 0.1% (mean +/- SE). In stationary-stage patients, the distribution and the percentage of positive cells were the same as those for the controls (1.1 +/- 0.1%). In the progressive stage, however, positive cells were distributed in both the upper portions of the hair follicles and the bulbar area, and the percentage of positive cells (4.9 +/- 0.3%) was significantly higher than that of controls. Staining for T, B lymphocytes and T cell subsets in the peribulbar infiltrates revealed a predominance of OKT4-positive cells (the OKT4/OKT8 ratio was from 3:1 to 4:1). This indicates that the number of OKT6-positive dendritic cells increases in the hair follicles of progressive alopecia areata and that these cells may play an important role in cooperation with T cells in the pathogenesis of alopecia areata.     

Leu-8/CD7 antigen expression by CD3+ T cells: comparative analysis of skin and blood in mycosis fungoides/Sézary syndrome relative to normal blood values.

Deficiencies of Leu-8 and CD7 antigens are exhibited by CD3+ T cells in the skin lesions of most patients with mycosis fungoides/Sézary syndrome. To determine whether these antigenic abnormalities are limited to involved skin, we studied Leu-8/CD7 expression in 21 skin lesions of mycosis fungoides/Sézary syndrome obtained from 16 patients and compared them with their peripheral blood leukocytes obtained concurrently. There was no correlation between Leu-8/CD7 values in skin lesions versus blood. Blood values were relatively uniform; most patients had 50% or greater of CD3+, Leu-8+ T cells and CD3+, CD7+ T cells. In contrast, skin values were highly heterogeneous; most patients lacked expression of Leu-8 or CD7 by the majority of lesional CD3+ T cells. Furthermore, Leu-8/CD7 antigen deficiency was present in lesional skin in one patient with mycosis fungoides but not in her concurrently sampled pityriasis lichenoides chronica or blood. These findings suggest that Leu-8/CD7 antigen deficiencies in skin lesions of mycosis fungoides/Sézary syndrome do not represent generalized antigenic abnormalities of CD3+ T cells in other body compartments and that within the skin, these deficiencies are disease specific within individual patients with more than one dermatosis. Comparative peripheral blood immunophenotyping of the patients with mycosis fungoides/Sézary syndrome and of the control subjects indicated that the control ranges of CD3+/Leu-8+ and CD3+/CD7+ T cells (33% or greater) extend lower than reported previously (60% or greater) and suggested that leukemic involvement in patients with mycosis fungoides/Sézary syndrome may correlate with percentages of CD3+, Leu8+ and/or CD3+, CD7+ T cells that fall below the revised control range.     

The cell population of cutaneous B-cell lymphomas

The cellular composition of the dermal infiltrates of eleven patients with a cutaneous B-cell lymphoma (four centroblastic lymphomas, two centroblastic/centrocytic lymphomas and five immunocytomas) was investigated. The distribution of both the neoplastic and the non-neoplastic cells (reactive T cells, macrophages and dendritic reticulum cells) in primary and secondary cutaneous B-cell lymphomas was very similar to that of B-cell lymphomas of the same type in lymph nodes. Reactive T cells and dendritic reticulum cells were only occasionally found in centroblastic lymphoma, but were very numerous in centroblastic/centrocytic lymphoma. The large majority of these T cells in centroblastic/centrocytic lymphoma showed the phenotype of activated T-helper cells (Leu-I+, Leu-3a+, OKT4+, HLA-DR+). In immunocytomas many T cells reactive with Leu-I, Leu-3a, and OKT4 but not with anti-HLA-DR antiserum, and varying numbers of dendritic reticulum cells were found. Since B-cell lymphomas in lymph nodes are the neoplastic counterparts of B-cell reactions which take place after antigenic stimulation in the different lymph node compartments, our results suggest that cutaneous B-cell lymphomas may be the malignant counterparts of similar B-cell reactions in the skin.     

Characterization of the mononuclear infiltrate in basal cell carcinoma: a predominantly T cell-mediated immune response with minor participation of Leu-7+ (natural killer) cells and Leu-14+ (B) cells

We investigated the peritumoral inflammatory infiltrate in 22 basal cell carcinoma (BCC) from 18 patients using a series of monoclonal antibodies. In all the 22 BCC the infiltrate consisted mainly of T cells (55 +/- 15%) and only in three cases an invasion of the tumor nests by these cells was observed. The T helper (TH) subset predominated over the T suppressor/cytotoxic (TS/C) subset (TH/TS/C ratio of 1.9 +/- 0.8). In 8 of 22 BCC mild infiltrate was observed with 48 +/- 13% T cells and a TH/TS/C ratio of 1.5 +/- 0.6. In 14 of 22 BCC moderate to heavy infiltrate with 59 +/- 15% T cells and a TH/TS/C ratio of 2.0 +/- 1.0 was observed. There was a significant difference in the percentage of T cells in BCC with moderate to heavy infiltrate and that in BCC with mild infiltration. The mean percentage of HLA-DR+ cells was 54 +/- 11%; Langerhans cells (LC) 4 +/- 5%; and Leu-M5+ (monocytes and macrophages) 16 +/- 11%. Less than 2% Leu-14+(B) cells were seen in the infiltrate. The mean percentage of Leu-7+ (natural killer) cells was 4 +/- 4%, and only 1 of 22 BCC Leu-7+ cells invaded tumor nests, contacting with tumor cells. From these results we concluded that T cells play a major role in the defence against BCC proliferation. The main role of Langerhans cells and Leu-M5+ cells may be that of antigen presentation. B cells and NK cells probably play a minor role in the local defence against BCC proliferation.     

The role of CD4 and CD8 cytotoxic T lymphocytes in the formation of viral vesicles

BACKGROUND: Herpetic vesicles caused by herpes simplex virus and varicella zoster virus, and hydroa vacciniforme (HV) are characterized by umbilicated vesicule formation. OBJECTIVES: To understand the histogenesis of umbilicated vesicles in herpetic vesicles and HV, we demonstrated the presence of the virus-associated molecules in the lesions, and the pathogenic role of cytotoxic T-lymphocyte (CTL) immune responses. METHODS: Phenotyping of infiltrating cells was carried out in biopsy specimens from herpes simplex, varicella, herpes zoster and HV, and compared with nonviral contact dermatitis. Viral antigens and Epstein-Barr virus-encoded small nuclear RNA (EBER) were detected by immunostaining and by in situ hybridization, respectively. Infiltrating CTLs expressing granzyme B and granulysin were determined by double immunostaining using confocal laser scanning microscopy. RESULTS: In all herpetic vesicles, the corresponding viral antigens were observed in the cytopathic keratinocytes, and infiltration of lymphoid cells was present in the upper dermis and around the vessels. In all HV lesions studied, EBER+ T cells made up 5-10% of the dermal infiltrates and the dermal infiltrates contained almost no CD56 cells. CTLs expressing granzyme B and granulysin were present in both herpetic and HV lesions, in which they made up 10-30% of the total dermal infiltrates, whereas they comprised less than 5% of the infiltrates of biopsy specimens from nonviral contact dermatitis. Confocal laser microscopic examination demonstrated that both CD4+ and CD8+ T cells expressed granzyme B and granulysin. CONCLUSIONS: CD4+ and/or CD8+ CTLs reactive to the virus-infected cells might be responsible for the histogenesis of herpetic and HV lesions characterized by umbilicated vesicles.     

T-cell subsets in lesions of systemic and discoid lupus erythematosus

In 6 patients with untreated systemic lupus erythematosus (SLE) in the progressive stage, and in 6 with discoid lupus erythematosus (DLE), an analysis of inflammatory infiltrates was performed in situ using the avidin-biotin-peroxidase complex (ABC) method with monoclonal antibodies. In all patients, over 75% of the infiltrates reacted with the pan T-cell antibody OKT3, but only sporadically with that of B-cell OKB7. In addition, a large number of the infiltrates were OKIal-positive, indicating that they were in an activated state. Many OKT8-positive cells were seen infiltrating the epidermis especially in the vicinity of basal keratinocytes. Staining for T-cell subsets revealed that the proportion of OKT8-positive cells (suppressor/cytotoxic) was from 2 to 3 fold higher than that of OKT4-positive cells (helper/inducer) in lesions of SLE. On the contrary, in DLE, a predominance of OKT4-positive cells (the OKT4/OKT8 ratio was from 1:1 to 3:1) was observed. Thus, our results provide further evidence that these 2 main types of LE show quite contrary findings on immunohistochemical analysis of T-cell subsets, and that besides the humoral immune mechanism, the cell-mediated immune mechanism may be involved in the pathogenesis of these disorders.     

Spitz痣和恶性黑素瘤浸润细胞的免疫细胞化学研究

用多种单克隆抗体,借助间接免疫过氧化物酶技术对1例Spitz痣和2例恶性黑素瘤(MM)Ⅱ, Ⅲ期的皮损进行了观察.结果见在Spitz痣与MM的炎性细胞浸润中,T淋巴细胞(OKT11⁺)占相当比例.在Spitz痣中,T_H/T_S(Leu3a⁺Leu2a⁺)的值与正常人皮肤中的比值相近,而MM的T_H/T_S比值降低.在Ⅳ期MM中,见炎性细胞减少的同时T淋巴细胞的比例下降,并且单核细胞(Monol⁺)数量较多,OKT6⁺细胞缺如.上述结果说明,Spitz痣与MM的炎性浸润细胞在免疫组织化学表现型方面有一定差别,并提示了在MM中细胞免疫功能的异常.     

The cell population in the cutaneous infiltrate of mycosis fungoides: in situ studies using monoclonal antisera

T cell antigens were studied in cutaneous sections from five patients with mycosis fungoides (MF). The method allowed cell counting to be undertaken for each monoclonal antiserum. OKT3 (pan T cell) antiserum confirmed the predominantly T lymphocytic nature of the infiltrate, labelling the majority of infiltrating cells. OKT4 (helper/inducer) antiserum positively labelled 90% of the lymphocytes identified as OKT3⁺. OKT8 (suppressor) antiserum marked only single or small groups of dermal lymphocytes, which comprised 24% of the cells identified as T lymphocytes. OKT6 (anti-Langerhans) showed positive labelling of dendritic cells in the epidermis and dermis. Fewer positively labelled epidermal dendritic cells were observed in sections from patients receiving PUVA, but no difference was found in the number of OKT6 positive dermal cells. The ratio of helper to suppressor cells in the dermal infiltrate significantly exceeded the normal circulating ratio.     

Different in situ distribution patterns of dendritic cells having Langerhans (T6+) and interdigitating (RFD1+) cell immunophenotype in psoriasis, atopic dermatitis, and other inflammatory dermatoses

Dendritic cells bearing Langerhans cell (OKT6+) or interdigitating cell (RFD1+) immunophenotype may be regularly detected within the dermis of chronic skin diseases characterized by a lymphohistiocytic (lymphoreticular) infiltrate. These 2 subsets of antigen-presenting cells within the dermis of lesions of exacerbating chronic plaque psoriasis, exacerbating nummular dermatitis (discoid eczema), atopic dermatitis, allergic contact dermatitis, pityriasis rosea, lichen ruber planus, and cutaneous lupus erythematosus were quantified using computer-assisted morphometry. The mean dendrite length per dermal dendritic cell was significantly higher for RFD1 than for OKT6 (74.4 +/- 0.98 microns vs 70.0 +/- 1.26 microns: p = 0.0023). The mean dendrite length per dermal dendritic cell was remarkably constant for each marker in the various diagnostic categories studied. Disease-specific patterns of total dendrite length and number (expressed per 100 infiltrating mononuclear cells) of these 2 dendritic cell types within the subepidermal infiltrates were obtained. Pityriasis rosea was characterized by its unique high percentage of OKT6+ Langerhans cells. Atopic dermatitis and psoriasis had relatively high percentages of both RFD1+ interdigitating cells and OKT6+ Langerhans cells. Nummular dermatitis had an intermediate number and total dendrite length for OKT6, but was relatively low in RFD1+ cells. Allergic contact dermatitis, lichen planus, and lupus erythematosus had low numbers and dendrite lengths for both dendritic cell subsets. It is suggested that pityriasis rosea is characterized by an abnormal migration pattern of Langerhans cells. Psoriasis and atopic dermatitis may be examples of diseases in which skin-localized antigen-presenting and T-cell-inducing events are continuously taking place. The other diseases may reflect inflammatory processes in which local antigen presentation is less relevant to the tissue reaction.     

Benign and malignant forms of erythroderma: cutaneous immunophenotypic characteristics

In order to determine if immunohistologic features are useful in distinguishing benign from malignant types of erythroderma, we studied the immunophenotype of lesional T cells in 20 patients (8 mycosis fungoides/Sézary syndrome, 12 benign) and found them to be generally similar. In all cases, the majority of T cells were Leu-1+, Leu-4+, and Leu-5+, as is typical of mature T cells. Although in most cases a majority of Leu-3+ (helper/phenotype) T cells were present, in 2 there was a majority of the Leu-2+ (cytotoxic/suppressor) subset and in 12 others, a significant minority (20%-40%) of these cells. Low percentages of Leu-2+ cells (less than or equal to 10%), resulting in high Leu-3+/Leu-2+ ratios, did not distinguish benign from malignant erythroderma. Leu-8 antigen deficiency was common in both mycosis fungoides/Sézary syndrome and benign cases (62% vs 75%, respectively). In contrast, Leu-9 antigen deficiency was present in only one patient in each group. The lack of combined Leu-8/9 antigen deficiency in our patients may be due to a heavy inflammatory T cell component, obscuring the antigen deficiencies seen in most nonerythrodermic mycosis fungoides cases. We conclude that immunophenotypic studies with the use of the current antibody panel show many similarities between benign and malignant forms of erythroderma, as well as some minor differences that may prove diagnostically useful if corroborated by future studies.     

Hyperkeratosis lenticularis perstans (Flegel's disease). In situ characterization of T cell subsets and Langerhans' cells

We report a patient with hyperkeratosis lenticularis perstans (HLP) manifesting as multiple reddish-brown hyperkeratotic papules on the lower extremities. Typical histologic features of HLP include hyperkeratosis, thinning or absence of the granular layer and a band-like infiltrate in the upper dermis underlying an atrophic epidermis. In order to determine the cellular composition of the infiltrate, skin biopsy specimens were studied immunohistochemically using a series of commercially available monoclonal antibodies. The dermal infiltrate consists predominantly of helper/inducer T cells (Leu-4+, Leu-3a+). Suppressor/cytotoxic T cells (Leu-2a+) were fewer at the periphery of the infiltrate. The majority of T cells were activated as they expressed HLA-DR-antigen. Large numbers of Leu-6+ Langerhans' cells were observed at the dermo-epidermal interface. Few natural killer cells (Leu-11b+) were noted within the dermal infiltrate. These findings support the hypothesis than an active cellular immune reaction involving the epidermis is of pathogenic importance for HLP.     

Leu-8 and Leu-9 antigen phenotypes: immunologic criteria for the distinction of mycosis fungoides from cutaneous inflammation

The distinction of mycosis fungoides from reactive cutaneous inflammation can be difficult. Unfortunately, since many reactive processes exhibit predominantly a mature helper T cell phenotype similar to that expressed by most cases of mycosis fungoides, standard immunologic marker studies have not been very helpful in differential diagnosis. To determine whether novel immunophenotypic criteria could be developed that correlate with the diagnosis of cutaneous involvement by mycosis fungoides, we studied the expression of Leu-8 and Leu-9 antigens by T cells in forty-one skin biopsy specimens from twenty-seven patients with mycosis fungoides and thirty-four skin biopsy specimens from thirty-three controls with a variety of benign cutaneous diseases. These antigens are expressed by the majority of normal T cells in the blood and lymphoid tissues but are often absent in T cell lymphomas or expressed by only a minority of tumor cells. Semiquantitative grading of the percentage of Leu-8+ and Leu-9+ T cells in our patients revealed that deficiency of these antigens (i.e., expression by less than or equal to 33% of T cells) was more prevalent among mycosis fungoides patients than among controls and became more specific for mycosis fungoides as the percentage of Leu-8+ and Leu-9+ T cells decreased. In initial biopsies, less than or equal to 33% of T cells were Leu-8+ in 82% of mycosis fungoides patients versus 15% of controls, while less than or equal to 10% of T cells were Leu-8+ in 52% of mycosis fungoides patients versus only 3% of controls.(ABSTRACT TRUNCATED AT 250 WORDS)     

Distribution of natural killer cells and lymphocyte subclasses in Jessner's lymphocytic infiltration of the skin and in cutaneous lesions of discoid and systemic lupus erythematosus

We studied the cell infiltrates in biopsies from lymphocytic infiltration of the skin (LIS), with six monoclonal T cell antigen-specific antibodies and compared the reactivity pattern with those in biopsies from discoid and systemic lupus erythematosus skin lesions and allergic contact skin reactions. A newly described antibody (NK₉) recognizing natural killer (NK) cells and activated cytotoxic T lymphocytes was included, and the numbers and activity of circulating NK cells was determined. Immunohistochemical staining revealed that the numbers of NK₉-positive cells were highest in LIS. The distribution of T lymphocytes (OKTii + ve), helper T cells (OKT₄+ ve), suppressor T celts (OKT8 + ve), Langerhans cells (OKT6 + ve) and activated T cells (anti-Tac + ve) in LIS differed from those in DLE, SLE and allergic contact reactions. However, the number of circulating NK cells (large granular lymphocytes) and the NK activity in peripheral blood were normal in LIS. We conclude that in LIS a distinct type of T cell activation occurs; the cause of this remains to be determined.     

Allergic contact dermatitis: novel immunohistologic features

Leu-8 is a novel antigen expressed by the majority of mature T cells and certain other cells. Recent studies of the allogeneic mixed leukocyte reaction indicate that both Leu-8+ and Leu-8- subsets of Leu-3+ T cells have important functions in cell-mediated immunity in vitro. In order to determine whether Leu-3+8+ and/or Leu-3+8- T cells are present in cell-mediated immune reactions in vivo, we studied the immunohistology of allergic contact dermatitis in 8 biopsies from 8 patients with positive patch tests and 3 biopsies from 2 patients with Rhus dermatitis. Both Leu-3+8+ and Leu-3+8- T cells were present in each biopsy. Only 1 case had a definite minority of the Leu-3+8+ subset. These results suggest that, analogous to in vitro systems, both Leu-8+ and Leu-8- subsets of Leu-3+ T cells are involved in cell-mediated immunity in vivo. HLA-DR+ keratinocytes were present in only 3 of 11 biopsies at days 3-7. No HLA-DQ+ keratinocytes were identified. We also confirmed prior findings that Leu-3+ cells are the predominant T-cell population, Langerhans cells are increased, and B cells and NK cells are rare. Furthermore, Tac and Ki-67 expression by T cells and Leu-3 expression by Langerhans cells tended to increase over time.